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ADDING VOICE MAIL TO YOUR COMPUTER - AUSTRALIA'S DYNAMIC ~ §-3ELECTR0NICS MAGAZINEi IN MUSIC ON HOLD " * FOR YOUR TELEPHONE * .* THIS NEW $4,600 BOSE MUSIC SYSTEM Remote Control Extender For VCRs ~ Low Cost 3-Digit Counter Module Power Supply For Burglar Alarms , METEX M-3650B DIGITAL MULTIMETER * * > <t * * * * * C en a: w ""' :I: 1- VIDEO LEADS * * # 1 SCART PLUG to 4 X RCA PLUGS (AUDIO) to 2 X BNC PLUGS (VIDEO) 1.5 MTR NOW ONLY $8.95 # 2 SCART PLUG to SCART PLUG 1.5 MTR NOW ONLY $6.95 # 3 UNIVERSAL VIDEO LEAD KIT 1 X 2 MTR RCA PLUG to RCA PLUG LEAD . 2 X RCA SKT to BNC PLUG ADAPTORS 2 X RCA SKT to PL259 PLUG ADAPTORS LL tu (!J a: 0 * * ONLY $99.95 <t * FIRE ALERT - SMOKE ALARM * * Photoelectric chamber. * ONLY $34.95 ELECTRONIC "SPELLRIGHT" ELLRIGHT" is a portable electronic spelling aid with a mass ive 80,000 d base of common and unusual word s. For use in business, scho ol, or just fun!!II Complete with mains power adaptor or can be operated on fou[ " AA" batteries (not included). NOW ONLY $69.95 NOW ONLY $6.95 I- "' z CB BAND SWR METER/POWER METER/ AM MODULATION METER/FM DEVIATION METER AND MATCHER ... ALL IN ONE UNIT! 0 C * ~ • 1111 D * * DIAL CORD · We've got reels of the stuff!!! 1O metre reel ... only 99 cents 1 WATT/10 W. ATT/100 WATT SWITCHABLE. .r NOW ONLY $39.95 •. . MODEL: MS-110 ~~::RN~n~~~E~~~~~:~~~R * 10 WATT/100 WATT SWITCHABLE. ..._ NOW ONLY $29.95 MODEL: DB-176 ,, "~• • * * N/0 or N/C relay outlet. * = * ...., .. ____ ....__ LL * 9 volt battery operated. LARGE 1999 count (3 .5 digit) LCD display with polarity indication and Bar High sensitivity. Graph. Test function. AC/DC V, OHM, AD/DC A, HFE, CAPACITANCE, FREQUENCY, Low battery indicator. DIODE TEST. Frequency rang e: up to 200KHz. LOUD 85db siren. Capacitance range: up to 20µ1. Only 125mm in diameter. ONLY $14.95 20 amp AC/DC. Continuity buzzer. JIC-636AR SMOKE DETECTOR For use in conjunction with an alarm system Includes case and test lead s. 12 volt supply voltage (from alarm panel). High sensitivity. * Op": :''._u• .r $13.95 DELUXE COMPACT DISC CARRYING CASE MINI-VAC VACUUM CLEANER Just the thi ng for cleaning com puter keyboards , printers, printed circuit boards, len s filte rs, etc . h _, "•AA !l!l"l!l ba l!l!l ttl!leri!!!leslll!I . ---~-•O•N•LY ...$.14•·•9•5... MOUSE MAT for your MOUSE 260mm x 220mm ONLY $14.95 AUDIO LEADS # 1 4 X GOLD RCA PLUGS to 4 X GOLD RCA PLUGS 1. 75 MTR. NOW ONLY $7 .95 Removable tray. (Holds 20 discs) Attracti ve leatherette cover: (Black) Felt lined interior. Lockable case with carry handle. ·--I- * .. _____....._~---Qlli * * * # 2 1 X STEREO 3 .5mm PLUG to STEREO 3.5mm PLUG 1.2 MTR. NOW ONLY $4.95 # 3 1 X STEREO 3 .5mm PLUG to 2 X MONO 3.5mm PLUGS 1.2 MTR. NOW ONLY $2.95 .' TOP VALUE! ONLY $21.95 11.:: " ~ .. # 4 1 X STEREO 3.5mm PLUG to 1 X STEREO 3 .5mm PLUG 1.2 MTR. NOW ONLY $3.95 VIDEO CASSETTE STORAGE CABINET ~ * Holds 8 VHS or BETA tapes. ..__ Now only $14.95 GOLD LINK VIDEO CABLES #1 1 X GOLD BNC PLUG to 1 X GOLD BNC PLUG dubbing cable. 1.7 MTR ONLY $5.95 # 2 VIDEO : 1 X GOLD RCA to 1 X GOLD RCA AUDIO : 2 X GOLD RCA to 2. X GOLD RCA stereo dubbing cable 1.75 MTR NOW ONLY $8.95 MORE SPECIALS IN THE CENTRE OF THIS MAGAZINE I * METEX M80 Jl.UTO-RANGING DIGIT AL MULTI METER Large 3. '7 5 Digit LCD Display. AC/DC V, Ohm , AC/DC A, Frequency. 20 amp AC/DC. Data Hold. µ.A range. DON'T PAY Continuity buzzer. $129.00 Diode test. NOW Freq up to 20KHz . Complete with probes ONLY and carry case . $69.95 ** * ** * * * SA VE OVER 45 % - - 127 YORK STREET SYDNEY 2 000 PH: (02 ) 267 1385 BUSINESS HOURS: Mon-Fri 8:30 to 5:30, T h u r s 8: 3 0 to 7 :0 0, Sat 9:00 to 1 :00 COAXIAL CABLE CONNECTOR CRIMPING TOOL COMPUTER DISKETTES D 5.25" D.S.D.D. $6.45 PKT 10 $60.00 BOX 100 This handy crimper has five different sized crimping jaws to suit most BNC, F, Mini M, M, N, and TNC coaxial connectors. Insulated handles with spring return. Push to release button. Jaw sizes: 1.72, 2.5mm. Jaw sizes: 5.4 , 6.48, 8.2mm. 5.25" D.S.H.D. 1.2mb ........ $14.95 PKT 10 3.5" D.S.D.D. $16.50 PKT 10 $120.00 BOX 100 * * * * ONLY $69.95 3.5" D.S.H.D. 1.4mb . .. . . . .. . $33.00 PKT 10 EDUCATIONAL SOLAR ENERGY KIT UNIVERSAL VIDEO DUBBING KIT Now you can experiment with solar energy ... the energy source of the future. This Solar Energy Kit is designed to let you build your own solar demonstrators right in your own home or classroom . The kit comes complete with: 1 x miniature DC motor 1 x Encapsulated solar cell 3 x Coloured spinner discs 1 x Solar Energy Booklet THIS GREAT KIT IS ONLY $5.95 ea -. 1 off 1 x RCA PLUG to 1 x RCA PLUG (VIDEO LEAD) 1.5 MTR. 1 off 2 x RCA PLUG to 2 x RCA PLUG (AUDIO LEAD) 1.5MTR. 2 off 5 PIN DIN PLUG to 2 x RCA SOCKETS. 2 off 3.5mm PLUG to RCA SOCKET ADAPTOR. 2 off BNC PLUG TO RCA SOCKET ADAPTOR. 2 off PL259 PLUG to RCA SOCKET ADAPTOR. ALL THIS FOR ONLY $11.95 Convert your Oscilloscope to a Spectrum Monitor with a Bandwidth of 100MHz C-400 WITTY MOUSE * Optical rotary encoder. * Max. tracking speed: 200mm/sec. * Resolution: 195 dots/inch. * Mouse driver software included. * IBM XT/AT compatible . The SPECTRUM PROBE is a low cost 100MHz Spectrum Analyzer in a handheld probe. Now see the frequency components of signals and noise. Use it as a sensitive RF detector. Locate radiated EMI sources. Check your RF signal generator. Check for stage gains in amplifiers. * PRICE TO CLEAR * * NOW ONLY $49.95 * * * Great value for only $395 FOAM EAR PADS TO SUIT SENNHEISER HEADPHONES THREE WAY AUDIO/VIDEO STEREO SWITCHING BOX Selects between three stereo audio/video inputs to one stereo audio/ video output. Can also be used as a stereo audio only selector as well. All sockets are standard RCA. Complete with 3xRCA to 3xRCA lead. * Replacement foam earpads to suit SENNHEISER outer ear.stereo headphones. * Yellow in colour ONLY $5.9512 pairs per set TWO WAY SPEAKER SELECTOR SWITCH Select between two sets of stereo speakers, switching from one to the other or selecting both at the same time. * Easy screw terminal inputs. 240 VOLT 120mm FAN NOW ONLY $16.95 600 WA TT INVERT Air Flow: 80 CFM AVAILABLE IN KIT OR BUILT-UP VERSION NOW ONLY $16.95 SAVE $12.00 12 VOLT 80mm FAN Air Flow: 30 CFM (approx.) NOW ONLY $14.95 At these prices it will BLOW you away MAIL ORDERS: P.O. BOX Q103, SYDNEY 2000 PHONE ORDERS: (02) 267 1385 FAX: (02) 261 8905 This inverter has the capability to produce 600 watts of mains power from a 12 volt car battery. $399/Kit ~ DilimOub Inrema1ionaf POST & PACKING $5-$25. . . $3.00 $26-$50 . . . $5.00 $499/Built $51 - $100 ..... $6.00 $101-$499 .. . . $8.00 $500+ FREE l~I ~ ::::J =::::J::::;:::;J .:::........... - _, _, _________, _, _. ~ =1 ~ ---- FEATURES 6 Voice Mail For Your Computer by Marque Crozman Converts your computer to a telephone answering machine THERE'S NO NEED to buy a second VCR for the bedroom. This remote control extender will let you operate your existing VCR from any room in the house. See page 24. 16 How To Make Dynamark Labels by Leo Simpson They're fast and easy to make 18 The Fluke 45 Digital Multimeter by Leo Simpson 20 30 60 104 It can be connected to a computer The Bose Lifestyle Music System by Leo Simpson The end of conventional hifi systems? The Story Of Electrical Energy, Pt.3 by Bryan Maher How alternators are excited & cooled Kenwood CS-6020 150MHz Oscilloscope Bob Flynn Has CRT readout & cursor controls Win A Bose Lifestyle Music System Take out a subscription and you are in the draw DO YOU FREQUENTLY have to place telephone callers on hold? Build this project and you can entertain them with music while they wait. Details page 40. PROJECTS TO BUILD 24 Remote Control Extender For VCRs by John Clarke Let's you operate the VCR from any room in the house 40 Music On Hold For Your Telephone by Jeff Monegal Plugs in parallel with your existing telephone 48 Alarm Power Supply With Battery Backup by Greg Swain For use with the Multi-Sector Burglar Alarm 54 Low Cost 3-Digit Counter Module by Darren Yates Use it as an event counter or as part of a larger project SPECIAL COLUMNS 64 Vintage Radio by John Hill The gentle art of scrounging valves THE SERVICEMAN did a lot of fiddling this month - well, pot twiddling actually. His problems start on page 74 . 74 Serviceman's Log by the TV Serviceman The risk of passing the buck 82 Remote Control by Bob Young The care & feeding of battery packs 93 Computer Bits by Jennifer Bonnitcha What to do when your computer goes bung; Pt.5 98 Amateur Radio by Garry Cratt Simple shortwave converter for the 2- metre band DEPARTMENTS 3 Publisher 's Letter 9 Mailbag 79 Subscription Page 90 Circuit Notebook 2 SILICON CHIP 106 Product Showcase 118 Back Issues 120 Ask Silicon Chip 122 Market Centre THIS 3-DIGIT COUNTER module can be used as an event counter or as part of a larger project. We show you how to build it starting page 54 . PUBLISHER'S LETTER Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Advertising Manager Paul Buchtmann (02) 979 5644 Mobile: 018 28 5532 Victorian Representative McDonald Woodside & Associates Pty Ltd, 143a Como Parade East, Parkdale, Victoria 31 94. Phone (03) 587 5155. Contact: Cameron McDonald. Your chance to comment on SILICON CHIP Welcome to the biggest issue of SILICON CHIP so far . At 124 pages, it represents another milestone in our progress. It is packed with articles aimed at that most important client of ours, you. Each month we talk with a lot of our readers and try to gauge what they like and dislike. You read the results of that process each month. This month though, we're taking a further step in giving you what you want. We are including a 4-page reader survey. It is right in the centre of the magazine. You can easily pull it out and fill it in. We have not numbered the pages of the survey, so that when it is pulled out, you won't be worried at some later stage that you have lost some pages. Please have a good look at the reader survey questions and take a few minutes filling in your answers. We really would like to know what you think. And if you would like to make extra comments about SILICON CHIP, please do so. It is not necessary to put your name and address on the survey but even if you do so, your answers will be entirely confidential. Please send your completed survey to SILICON CHIP, PO Box 139, Collaroy, NSW 2097. The sooner you do it, the sooner we'll be able to collate the results and act upon them. While you are in the mood for filling in forms, why not enter our Bose competition by taking out a subscription'? It's a great prize and there are other prizes thrown in for the three months' duration of the promotion. The details of the Bose promotion are shown on pages 104-105, while the subscription coupon is on page 80. Enjoy reading this issue. See you next month. Leo Simpson Regular Contributors Jennifer Bonnitcha, B.A. Garry Cratt, VK2YBX John Hill Jim Lawler , MTETIA Bryan Maher, M.E., B.Sc. Jim Yalden, VK2YGY Darren Yates Bob Young Photography Glen Cameron Editorial Advisory Panel Philip Watson, MIREE, VK2ZPW Norman Marks Steve Payor, B.Sc., B.E. SILICON CHIP is published 1 2 times a year by Silicon Chip Publications Pty Ltd. All material copyright (c). No part of the contents of this publication may be reproduced without prior written consent of the publisher. Typesetting: Magazine Printers Pty Ltd, Rozelle, NSW 2039. Printing: Macquarie Print, Dubbo, NSW 2830 . Distribution: Network Distribution Company. Subscription rates: $42 per year in Australia. For overseas rates, refer to the subscription page in this issue . Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. Editorial & advertising offices: Unit 39, 5 Ponderosa Pde, Warriewood, NSW 2102. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. ISSN 1030-2662 SEPTEMBER 1990 3 f/elte#«f s~ 4, I Our prices are like the business . . . BOARD SOLUTIONS Pty Ltd I MOTHERBOARDS 10MHz XT, (640K) OK RAM 10MHz XT, (1MB) OK RAM 31MHz XT286 OK RAM Baby 286 12MHz OK RAM Baby 286 12MHz OK RAM VLSI Baby 286, 12MHz VLS I OK Neat 286, all-in-one, OK RAM 16MHz NEAT 286 OK RAM I 20MHz 286 OK RAM 16MHz 386SX, OK RAM 25MHz 386, 32K Cache, OK Neat 33MHz 386, 32K Cache , OK I ***NEW!!! BUILT-UP SYSTEMS*** M1010 M1000 M1020 M2015 M2030 M2020 M2010 M2040 M2045 M3000 M3010 M3020 115.00 149.00 225.00 399.00 449.00 499.00 545.00 599.00 845.00 895.00 1995.00 2795.00 Z9300 Z9380 Z9400 Z9480 Z9500 Z9200 29.95 32.95 7 .95 8 .95 275.00 32.95 Z9212 Z9112 Z9000 Z9010 Z9020 Z9210 Z9540 Z9210 Z9550 Z9555 Z9560 Z9565 Z9570 Z9575 Z9580 Z9585 Z9680 Z9690 12.00 4.95 24.95 39.95 49.95 5.45 795.00 5.45 449.00 495.00 549.00 649.00 649.00 749.00 949.00 1099.00 295.00 295.00 II CHIPS 1M RAM Chip - 1OOnS 1M RAM Chip - 80n S 256K RAM Chip - 1OOnS 256K RAM Chip - 80n S 8087-2, 8MHz Co- Processo r 4 X 256K RA M Chip, 100nS 4 X 64K RAM Chip , 120nS For VGA card 64K RAM Chip - 120nS NEC V20 Chip NEC V20 Chip, 10MHz NEC V30 Chip, 10MHz 64K RAM Chip - 1OOn S 80387SX 16MHz Co-P rocessor 64K 1OOns RAM Ch ip 2C87-8MH z (equiv 80287/8) 2C87-10MHz (equiv 80287/10) 2C87-1 2MHz (equiv 80287 /12) 2C87-20MHz 3C87-16MHz (equiv 80387/16) 3C87-20MHz (equiv 80387/20) 3C87-25MHz (equiv 80387/25) 3C87-33MHz (equiv 80387/33) SIMM Module , 1MB 80ns SIPP Module, 1MB so ns XT (8088) 10MHz System XT (8088) 31 MHz System 286-12 (80286) System 286-12 (80286) VLSI System 286-12 (80286) NEAT System 286-20 (80286) 20MHz System 386S X (80386SX)16MHz System 386-33 (80386) 33MHz System 895.00 1095.00 1225.00 1595.00 1695.00 2050.00 1995.00 4795.00 All systems are fully built and tested, with RAM fitted. Simply add the video card and monitor of your choice. 12 months warranty applies to all Board Solutions Systems. INTERNAL FLOPPY DISK DRIVES YE-Data 360K YE-Data, 720K/1.44M D3000 drive Plus Frame YE-Data, 1.2MB I X1010 X1030 X2859 X2861 X2860 X2862 X3861 X3863 EXTERNAL FLOPPY DISK DRIVES D5500 D3000 D3010 D5510 INTERNAL HARD DISK DRIVES NEC 42MB, 28mS 3.5in D8000 plus Frame M'scribe 40MB AT BUS 3.5in Kalok 20MB 40mS Seagate 20MB ?Oms RLL inc XT controller. Seagate 20MB 65ms RLL inc XT controller Seagate 30MB 65ms MFM inc XT controller Seagate 40MB ?Oms MFM inc XT controller Seagate 5.25in 40MB 40ms RLL Seagate 5.25in 40MB 28ms RLL Seagate 5.25in 65MB 40ms RLL Seagate 5.25in 65MB 28ms RLL Seagate 42MB 24ms V/C I 149.00 184.95 199.00 175.00 For Amiga 500, 1000, 2000, 3.5in 880K For Amiga 500, 1000, 2000, 5.25in 360/880K For Commodore PC1 , 5.25in 360/720K 40/80 track For Atari ST series, 3.5in 720K For Atari ST series, 5.25in 360/720K 40/80 track For Amstrad PC1512/1640, 3.5in 720K For IBM XT, 3.5in 720K XT For IBM AT, 3.5in 1.44MB For IBM XT, 5.25in 360K For IBM AT, 5.25in 1.2MB For TOSHIBA laptop series, 5.25in 360K For TOSHIBA laptop series, 5.25in 1.2MB II D8000 D8010 D8020 D8100 745.00 775.00 795.00 399.00 D8200 529.00 D8210 575.00 D8220 629.00 D8230 D8240 D8250 D8260 D8270 D8390 675.00 775.00 795.00 849.00 899.00 849.00 D9500 249.00 D9510 299.00 D9520 D9530 299.00 299.00 D9540 299.00 D9550 D9560 D9570 D9580 D9590 269.00 299.00 329.00 299.00 329.00 D9600 349.00 D9610 399.00 MICE & JOYSTICKS Joystick PC/XT/AT 3 Button Serial Mouse Mouse Mat J1000 J1030 J1040 34.95 69.95 7.50 I MONITORS Monitor, 14in Monitor, 14in Monitor, 14in Monitor, 14in Monitor, 14in Monitor, 14in TTL, Amber TTL, Green TTL, Paper White EGA VGA Multisync I MICRO CHANNEL Dual Sync Adaptor, PS/2 2MB RAM Card, PS/2 OK RAM 8MB RAM Card, PS/2 OK RAM M9000 M9010 M9020 M9030 M9040 M9050 249.00 249 .00 249 .00 599.00 749.00 899.00 PHONE OR FAX NOW FOR LATEST PRODUCTS. PRICES AND INFORMATION OOPS! OVERSTOCKED ALL-IN-ONE "AT" MOTHERBOARD: SLASHED BY $1 DO - ONLY WHILE THEY LAST! Here ' s a sensational bargain - if you' re quick! We're dramatically overstocked on these superb '286 motherboards which include serial and parallel ports and hard/floppy controller on board. Update your old XT snail to AT performance! Normally fantastic value at $545.00; Our suppliers have really because we 're overstocked we 've done it this time: they didn't slashed the price - only while stocks see the decimal point and last - by a massive $100.00 I MC1000 299.00 MC1010 349.00 MC1020 599.00 WHATA BOO-BOO! sent ten times our order. Ou r difficulty is your opportunity: YOU REAP THE BENEFIT! HURRY! THIS MONTH ONLY OR UNTIL CURRENT STOCKS SOLD ! RAM CARDS 1/0 CARDS 2 Ser. 1 Parallel Games, Parallel & 2 x Serial Chip Set & Cable suit 11040 Multi 1/0 Card XT only Multi 1/0 Card , 2 Ports all 4 drive types supported (XT Only) Parallel Printer Card (XT/AT) Serial PortCard X 1 (XT/ AT) Serial PortCard X 2 (XJ/AT) 1/0 Plus Card - XT Only Serial/Parallel Card - XT/AT 2 Serial, 2 Parallel, AT Games, Par, Serial XT/AT Multi-Serial Card, 4P-AT I i1080 i1110 i1041 i1000 74.95 99.95 29.95 129.00 i1010 i1020 i1030 i1040 i1050 i1060 i1070 i1080 i1090 164.95 29.95 54.95 69.00 99.00 64.95 84.95 89.00 245.00 I VIDEO CARDS VGA Card , 800 x 600 (256K) VGA Card, 1024 x 768 (512K) Magic Combo CGA Card EGA Card Mono Hercules Card, 16MHz operation + Parallel Port I V1000 V1010 V1020 V1035 299 .00 399.00 129.00 179.00 V1040 99.00 I POWER SUPPLIES 200 Watt PSU Suit Tower Case 200 Watt PSU Suit Baby T Case 150W PSU , Circuit Board 150W Switching PSU - XT 200W Switch PSU - Baby AT 200W PSU, Baby AT, L Type 220W Switching PSU -AT 200W PSU With Battery Backup 150W PSU Cap. 220nF/200V I P2020 P2030 P1500 P1510 P2000 P2010 P2200 P2040 P9000 195.00 149.00 85.00 124.00 149.00 149.00 195.00 695.00 3.95 I KEYBOARDS 84 Key Keyboard XT/AT 101 Key Keyboard, XT/AT 101 Key Keyboard + TrackBall K1000 K1010 K1020 95.00 115.00 199.00 RAM Card, OK RAM , XT only 2MB RAM Cd, OK LIM/ EEMS AT 2MB RAM Cd, OK LIM/ EEMS XT 6MB RAM Card , -OK RAM 4MB Fast Card Suit 20MHz +SX 32 Bit RAM Card 25 + 33MHz R1000 R1010 R1020 R1030 R1040 R1050 INTERFACE CARDS 99.00 265.00 245.00 295.00 299.00 349.00 DISK CONTROLLER CARDS Floppy Disk Card, 4 Ports 360K Disk Cont 4 port, 2In 2Ex or 4In Floppy Disk Card All Drives ESDI Hard Disk Cont Card - AT ESDI HOD/FOO Card - AT Hard Disk Cont, 1 :1 lnt. AT HDD/FDD Cont, 1 :1 lnt. AT Hard Disk Cont, 1 :1 lnt. RLL , AT HDD/FDD Cont, 1:1 int, RLL, AT SCSI HOD/ FOO for AT Hard Disk Controller, XT Hard Disk Controller, RLL-XT I E1000 E1030 E1010 E1040 E1050 E1060 E1070 E1080 E1090 E1105 E1110 E1120 I CASES Hinged, Baby AT Full Size Hinged AT Case Hinged Baby ATw/200W PSU Slimline 'XT' or 'AT' with PSU 3.5in Hard Disk Ext. + Cable 5.25in Floppy Disk Ext. + Cable 5.25in Full Height Ext. + Cable 5.25in Mount for 3.5in Drive Baby Tower .Case AT Baby Tower Case + 200W PSU Tower for 6 Dev. (4 front, 2 rear) Tower for 6 Dev. (4 front, 2 rear) & 200W PSU Tower for 6 Devices, (6 front) Tower for 6 Devices, (6 front) + 200W PSU Case, hinged XT I 55.00 134.95 99.00 349.00 425.00 245.00 275.00 249.00 285.00 275.00 134.95 154.95 C1000 C1005 C1010 C1020 C1030 C1040 C1050 C1060 C1070 C1080 C1090 139.00 199.00 249.00 275.00 99.00 115.00 125.00 25.00 189.00 325.00 "399.00 C1100 C1120 549.00 399.00 C1130 C1140 549.00 95.00 48 Line 1/0 Card F1130 Serial RS-422 Adaptor F1140 Industrial 1/0 Card F1150 Universal Wire-wrap Card F1030 Dual Serial RS-422 Card F1040 80286 Speed-up Card F1050 IEEE 488 Interface Card F1060 IEEE 488 Interface Card- National Compatible F1070 A-0/0-A Converter, 12 bit, 1 Ch. F1080 A-D/0-A Converter, 12 bit, 2 Ch . F1090 Clock Card - XT F1100 EPROM Writer Card F11 10 Games Card- 'XT'& 'AT' F1120 110.00 135.00 445.00 125.00 195.00 495.00 445.00 595.00 199.00 599.00 49.95 245.00 35 .00 NETWORK SK Ethernet 8 bit with 'T' Adaptor 16K Ethernet 16 bit with 'T' Adaptor Ethernet 50 Ohm Terminator Thin Ethernet Cable , 25 feet Thin Ethernet Cable , 50 feet Thin Ethernet Cable, 75 feet Auto Boot ROM for NEE1 Workstation , 12MHz Diskless, with 1MB RAM N 1000 399.00 N1010 N1020 N1030 N1040 N1050 N1060 449.00 12.75 35.00 49.00 62 .00 79.95 N2000 1695.00 CABLES I OH NOi We 've run out of room to show you our great range of cables, connectors and gender benders. For details of any of these products, call Board Solutions today. No obligation, of course! PHONE OR FAX NOW FOR LATEST PRODUCTS. PRICES AND INFORMATION MAJOR AUTHORISED DEALERS Adelaide Broken Hill Cannonvale Charlestown Coifs Harbour Devon port Glen Innes Hobart lnverell Ipswich Leeton Lightning Ridge Lismore Mackay Morwell Mount Gambier Mt Isa Mudgee Nambour Narrabri Port Lincoln Townsville Wagga Wagga Windsor Microtronics Hobbies And Electronics Nth . Qld. Adv. Technology Newtronics Coifs Harbour Electronics Al Electronics John Sommerlad Electronics Beta Electronics lnverell Computer Bits ACR Computers Leeton Audiotronics Cycle & Sou nd Decro Electronics Steven 's Electronics Morwell Electronics Hutchesson's Communic. Outback Electronics Headware Nambour Electronics Namoi Computers . Bassham's TV & Computer Super Sol ex Phillip's Electronics Windsor Communications 2121799 884 908 466 898 439 600 525 684 248 322 323 661 348 232 223 769 281 6155 532 081 290 579 214137 511 723 346133 250 400 433 475 723 895 411 604 923 274 822 788 724 466 216 558 775 935 NEW DEALERS REQUIRED IN BRISBANE, DARWIN, MELBOURNE AND HOBART. PLEASE CALL ! • 14 Day money-back guarantee (except software) • At least 6 months warranty on all our products. • Mail orders are our speciality! • Road Freight on normal size items is $9.00 • Insurance $1.00 per $100 of order value • All prices INCLUDE sales tax • We accept Visa, Bankcard, Mastercard and Post Office COD • Call for latest price list • Special prices apply until September 31, or while stocks last! • Leasing facilities available: just ask! • Government pricing available on request PO BOX 1120, LANE COVE NSW 2066 TEL (02) 906 5696 FAX (02) 906 4592 How would you like to have Voice Mail on your IBM computer? Far better than boring old phone answering machines, Voice Mail allows messages to be left on a computer for one or a hundred people. Interested? Read on. By MARQUE CROZMAN Have you ever arrived home only to find that the beast you call a telephone answering machine has Baten the tape with all your telephone messages for the day? Or that the youngest of your siblings has extracted it with little jam fingers and used it to create a strange kind of confetti? Well then, this is for you. Now there is the tapeless answering machine, the Voice Mail Card for the IBM PC. The Voice Mail Card is not only an answering machine but is more like a bulletin 6 SILICON CHIP board for voice messages. It will answer incoming calls automatically, play your greeting message, then record the incoming message. The incoming messages can be placed in a "public mail box" for everyone to hear or they can be placed in private mail boxes so only the owner of that mail box can access the message. By using a tone dialling telephone, you can then phone up the system to listen to, record or delete the massages, or distribute them to other users. To operate the Voice Mail card, you need an IBM PC/XT/AT or compatible with at least 512K of RAM, MS-DOS 3.0 or later, a touch tone phone, and two floppy drives , or a 360K floppy drive and a hard disc of at least 10 megabytes. Physically, the Voice Mail card is about half the length of the standard IBM card and its mounting plate/bracket is fitted with two US modular phone sockets, a 3.5 millimetre jack socket for an external speaker and a volume trimpot. Installing the Voice Mail card is straightforward. You simply remove the top cover from the computer, plug the card into a spare expansion slot, connect the phone to the card, and connect the card to the phone line. Before making the connections, your touch tone phone must be terminated with a US modular plug to fit the card socket. Be careful not to get the phone and line plugs mixed as the manual warns that if the two are switched, Using Your Computer As Answering Machine the card may be damaged. The optional external speaker is handy. It enables you to hear the messages as they come in and also to play back messages. Otherwise, you can listen to messages through the handset. Address range The address range for the card is a potential problem, depending on what other peripherals or cards are used in the system. If a clash occurs, the card will either not work or respond erratically. To solve this, you have to change the jumpers on the card to an address space not already in use. We found that one set of addresses was also used by the multi I/O card in the computer and this caused the card to respond erratically. All the software for the Voice Mail card comes on a standard 5 ¼-inch floppy. Installing it is pretty straightforward. You need to create a directory called 'VMC' and then copy all files on the disc across to this directory. Then, you run the installation program. The manual is necessary for ·the next part as the program asks some fairly technical questions about touch tone duration and spacing etc. Luckily, we found that the default settings worked well and had no need to change anything. The next screen asks for a transfer code. This feature is for telephone systems that allow you to transfer calls to other extensions. The object of this is to allow you to transfer your call to another phone when you call up the system; ie, if the system is set up in a business environment, callers can still contact people who are working back late on their own extensions, while the card is taking incoming messages for people who The software comes on a standard 5¼-inch flopy disc and is easy to install. During installation, the user records the messages and selects other options from the on-screen displays. have gone home. To access this feature, you need to wait for the 8-second delay and then dial"##", the extension number of the person concerned and then "# #" again. This transfers the call - but I am getting ahead of myself. The following screen outlines another feature of the card, the "broadcast" mode. The mode prevents callers from leaving public messages at certain times of the day; ie, during business hours. This feature is optional and can be toggled on and off. The Voice Mail card supports most graphics cards but only prompts you as to whether or not your monitor is colour or not. The rest of the install software records the messages that the system needs for its outgoing messages and various user prompts. These messages are recorded using the phone connected to the card (referred to by the manual as the 'local phone'). Operation There are two pieces of software for the Voice Mail card. The first is for monitoring incoming calls, storing them to disc, and sending mailing messages. This operates in background mode, leaving the computer free for other tasks. When calling in, the system will either answer on the 2nd or 5th ring; the latter if there are no messages in the public mail box. On answering, the system replays the greeting message, then there is an 8-second pause before you can leave your message. This delay is a problem because SEPTEMBER1990 7 _.-,.,, ~· ~ An IBM PC/XT/AT or compatible computer with 512K of RAM is necessary to operate the Voice Mail card. The unit is about half the length of a standard IBM card and simply plugs into one of the expansion slots. 5 ¼-inch diskette slotted into the back page of the manual. So what's it like? it confuses people who are not used to it and it can be a pain for anyone who is in a hurry. However, the 8-second delay does have a purpose. During this pause, you may select various functions using the keypad on a touchtone phone. These include call transfer (mentioned above), sending messages to private mail boxes, playing back your own messages, or changing various messages the system uses. Even so, I feel there should have been an option to toggle this 8-second delay on or off, to avoid confusion. I got around the problem by telling callers about the pause in the greeting message but some callers were still caught by it. The second piece of software looks after all functions that need keyboard operation. This software is window driven and pull down menus allow you to select options for each function. These include the creation of mail boxes, administration, handling of messages, distribution of messages, and phone book operation. The phone book operates 8 SILICON CHIP in the same fashion as its 'paper' equivalent but will dial the number for you, provided you are connected to a tone telephone line. Just a brief note on that last point: even if your local telephone exchange does not have tone dialling, you still need a standard tone phone for the card to work properly. Documentation The documentation reads as though it has been translated by an illiterate computer but putting that aside, it is self-explanatory and will get novices up and running fairly quickly. Seven A4 pages supplement the manual with amendments and updates to the software. The manual is quite detailed and explains all functions in a clearly defined manner. Each function is explained in summary then later in greater detail. Appendixes at the back outline the technical details, a glossary of terms and a quick guideline to get you up and running fast. The software comes on a Most callers, unless you tell them, are blissfully unaware that they are talking to a computer it's just like talking to any phone answering machine and people get just as tongue-tied. I like it because there is nothing mechanical to go wrong and note this: you can store those messages forever on diskette, if you want to. And another point, it keeps a record of precisely when each message was left, something that ordinary phone answering machines can't do. On the debit side of the ledger, if you want it on at all hours, it does mean your PC is running continuously while you are out. That might be a problem for some users. We would recommend that the Voice Mail Card not be used during thunderstorms without surge protectors on both the power and telephone lines. The Voice Mail Card retails for $245 and is available from Rod Irving Electronics, 74 Parramatta Rd, Stanmore, NSW 2048. Phone (02} 519 3134 or, in Melbourne, (03} 663 6151. 1§:;i MAILBAG Feedback on radio kits Enclosed is payment for the renewal of my subscription for another year. Keep up the good work. I wish to bring to your attention a problem I have observed in the PCB artwork for the mini stereo transmitter published in the October 1988 issue of SILICON CHIP. If one end is not cut off correctly, the antenna output is shorted. It's always the simple things in life that make life frustrating, to misquote the Kelloggs ad. The transmitter sounds quite good and it's amazing that the whole thing runs on only 1. 5 volts. Another very good kit of yours is the AM Stereo Radio. The whole thing went together so easily, and it worked first go. However, it sounded even better after I aligned it. It's a pity that the radio stations in Sydney can't improve the music they transmit! The sensitivity of this radio is also something fantastic. It will pick up stations in Wollongong and Gosford during the day. Mark Allen, Gore Hill, NSW. Specialty chips are difficult to get These days, more and more project designs are including specialty chips not carried by our turnover conscious electronics stores. Consequently, construction of such projects is made more difficult, as the specialty supplier ring around begins. The problem raised itself recently when l was trying to source a "doorbell" chip. I remembered your UHF doorbell of August 1988, and eventually dug up the relevant article. It uses the SAB0602, yet doesn't mention any more about that particular IC. I realised that it was a Siemens chip from the similarity to the dreadful SAB0600. One wonders what went through the minds of the Comeng engineers when they decided to put this horrific sounding creature inside the NSW Railway's Tangaras. I'm still sure it was a joke that went wrong! Might I suggest that when presen- ting projects using non-standard components, a "shoparound" column should be included. Better still, why not a feature article on ·semiconductors, their labelling, identification, and supply? Accompanying the article could be a table of suppliers for each of the state capitals. I for one would benefit from a further understanding of IC labelling in particular and I'm sure many other readers are in a similar position. Thanks for the magazine. Keep it up! Greig Sheridan, Ashfield, NSW. The story of electrical energy Congratulations on the Bryan Maher series describing electrical energy. The man is not only clever but thoroughly readable and informative. The conclusion of his mammoth series on electric railways left, for me, a large hole in SILICON CHIP. This series had captured my interest from the jump and was always the first article to which I'd turn upon receiving each issue. Thankfully, that hole is now filled by a writer I enjoy on a subject in which I have much interest. By starting this new series, you have given me yet another reason to be glad that I subscribe to SILICON CHIP. Julie Kentwell, VKZXBR, Springwood, NSW. Listing for computer clubs The secretaries of user groups and computer clubs who read your magazine will be interested to know that it is now possible for them to arrange, through Telecom Business Offices, an entry in the Yellow Pages under the new classification: "Clubs - Computer". A charge is made for a white pages entry; eg, the secretary's private number and address preceded by the name of the group/club and this is a pre-requisite for the free Yellow Pages entry as above. We in Canberra, with its rather mobile population, have been conscious of the need for this for some SILICON CHIP, PO Box 139, Collaroy Beach 2097. years and we think that others will want to take advantage of it too. We are informed that the first cab off the rank will be the 1991 Sydney Directory, entries for which will close in a few months time. K. W. Shands, Secretary, Commodore User Group, Curtin, ACT. How about a reprint of earlier issues? I am one of the many readers who would like a copy of the November 1987, December 1987 and January 1988 issues of SILICON CHIP but they are sold out. Why don't you see how many people are interested in a copy? It may be economically viable to print another edition. Jason Semple, Preston, Vic Extended guarantee on boards with VLSI chips In the July issue of SILICON CHIP, Mr R. Hobson of Glenreagh, NSW wrote about the boards supplied by Electronic Solutions which have surface mounted VLSI chips. I would like to answer his concerns as follows. First, he says that if the boards had chip carriers to hold the VLSI chips, this would solve the "repairability" of the boards. The reason that manufacturers are moving away from chip carriers is that because of the large number of connections (and this number is increasing as larger scale integration is being achieved), the chip carriers themselves are unreliable and are tending to fail after a period of time. Second, special tools are required to remove and replace VLSI chips. Third, VLSI chips are extremely reliable. This makes products that have a small chip count due to the use of VLSI chips very reliable as well. Therefore, as Mr Hobson has brought this to our notice, from July 1990, all boards with VLSI chips that are supplied by Electronics Solutions will carry a full 12 months parts and · labour warranty. Ian Hardwick, Managing Director, Electronic Solutions, Lane Cove, NSW. SEPTEMBER 1990 9 2 SECTOR BURGLAR ALARM CONTROL UNIT This Control Unit features variable entry and exit delays, LED status indicators, alarm driver circuitry, timed and latched outputs, two separate sector inputs, and the provision to add extra sector boards as required. Cat K-8401 ALARM POWER SUPPLY MODULE Finally ... a sophisticated BURGLAR Alarm Power Supply you can build yourself! It not only provides a 12 volt supply for your alarm , but recharges your back-up battery and automatically switches the supply between battery and mains should their be a power interruption. f·ii-ii"""i:~ ~~=:,.:.il Transformer to suit Cat M-1990 ,.., 4 DIGIT CAPACITANCE METER Use it in the workshop, use it in the laboratory. This meter can measure capacitance from 1pf to 9999uf in 7 ranges. It is mains powPred, which means a big bright LED display, and it has an accuracy of better than± 1%. Supplied complete with all components including plastic case, deluxe pre-punched silk screened front panel , plus alligator clips and BNC plug for test lead. CatK-7500 ~ ~ S129QQQ[2] □ :3995 Q[I] §a~ 2 SECTOR MODULE Expand your K-8401 Burglar Alarm Control Unit. Add as many of these Sector Modules as you need. They hold two sectors, each with LED status indicators and isolating switches. Cat K-8400 s12es Q DIGITAL SINE/SQUARE WAVE GENERATOR t€?D This new Digital Sine & Square Wave Generator uses high speed CMOS ICs and a digital filter to produce waveforms over a frequency range of 0.1 Hz to 500kHz. It also features a 4-digit frequency readout, an output level control, and course/fine frequency adjustm;e:::nt::.. . _ _ _ _ _ _ _ _........_ Cat K-7350 COMBINATION LOCK This keypad combination lock can be used to operate your K-8401 or other Burglar Alarms. Works with solenoid door locks too! It can even be wired to trigger the alarm when the lock detects repeatedly incorrect entries. The kit includes a high quality keypad . Cat K-8403 s149 QQQ[2] s29es Q LOGIC PROBE DUAL TRACKING +/- 5OV POWER SUPPLY This invaluable kit comes with a special purpose case and includes test leads. LED indicators on the probe will identify logic HI , LO or PULSE states in both TTL and CMOS logic circuits ~24 95 v~ UHF TRANSMITTER KEY \P " This new design uses a SAW filter for improved frequency stability and eliminates the need for transmitter alignment. It features a flashing LED to indicate the button is being pressed and an automatic cut-out after 10 seconds if the button is accidently held down . CatK-3259 ~ ~ s29es Q ~ This power supply can really deliver the goods with variable output from Oto 100 volts DC! Ideal for TV servicing. • Variable current to 1.7 Amps (0-87V) 1 amp<at> 100V ~ • LED indicator for ripple exceeding 5mV p-p ~ • Short-circuit protected • Pre-punched & screened front panel Cat K-3465 s249 :1601/ 1 &A DUAL TllAClllHO POWUl 14.1Pf1LY C .,... = 11I nn _ _; QQQ[zl KEY Kits marked with this symbol involve mains power wiring . Take extreme care when working with this equipment. O () 0.0,0UT L(,~0 •r,;tfl f1!iJilill ~ ~ O .. "' ~ Degree Of Simplicity QSimple QQ Intermediate QQQ Detailed • YAESU FRG-9600 SCANNER The FRG-9600 scanner is capable of covering the complete 60 to 905MHz VHF/UHF spectrum in all modes- FM, AM , CW, and SSB to 460MHz... yes the lot! At a touch of a button it opens up an exciting world of communication. Frequency : Conversion : 60-905MHz (up to 460MHz for SSB) Triple (FM-n , AM, SSB) Double (FM-w) 47.754MHz, 10.7MHz, 455kHz FM-n 5/10/12.5/25kHz FM-w 100kHz AM-n 100Hz/1 kHz AM-w 5/10/1 2.5/25kHz SSB 1OOHz/1kHz 0 ~ 2att into 8ohms < 10% THD S8V8 DC12-15V IFs: Tuning steps: All Band, All Mode Receiver YAESU FRG-8800 HF Memories: Audio Output: Voltage: From the world 's leading manufacturer of amateur radio equipment. • Covers 150KHz to 30MHz • All mode, AM, LSB, USB, CW, FM • Large digital display, • S/SINPO graphics indicator with keypad freq. entry • Dual 24-hour clock • Wide-band VHF option • CAT computer control option (118-174MHz) • Selectable tuning rates • 2 Year Warranty Cat D-2825 5 s1295 $50f 899 (Sept Only) Cat D-2820 SEPTEMBER BONUS! Buy the FRG-8800 in September and receive FREE the D-2823 VHF Frequency Converter (118-174MHz) worth $149 . SPECIAL DEALS ON ACCESSORIES D-2845 D-2843 FRA-7700 FRT-7700 Active Antenna $129 normally $149 Antenna Coupler $139 normally $159 IN-STORE AMATEUR RANGE EXPANDED \lil VA ESU V 4 CORE SHIELDED FLAT CABLE Cat W-2039 IDC GRADE CABLES Cat W-2750 26 way $2.95/m 30m pack only $60 save $15! Cat W-2752 34 way $3.50/m 30m pack onl y $80 save $8.50 !!!:!===:U 95 Radiation cross linked, flame retardent, heat shrinkable, military grade polyolefin tubing. Now with that sort of description it has to be good! Sold in 1.2m lengths ; shrinks in diameter by 2: 1 ratio. SIZE CAT NO COLOUR PRICE 10 UP W-4100 Black W-4102 Colours W-4104 Black W-4106 Colours W-4108 Black W-41 10 Colours W-4112 Black W-411 4 Colours W-4116 Black W-4118 Colours W-4120 Black W-41 22 Colours W-4124 Black W-4128 Black #MIL-1-23053/5 TINNED COPPER WIRE 0.71mm diameter, 100g roll. Cat W-3015 SAVE 30%! HIGH QUALITY HEAT SHRINK TUBING 1.2m x 1.6mm 1.2mx 1.6mm 1.2m x 3.2mm 1.2m x 3.2mm 1.2m x 4.8mm 1.2m x 4.8mm 1.2m x 6.4mm 1.2m x 6.4mm 1.2m x 9.5mm 1.2m x 9.5mm 1.2m x 12.7mm 1.2m x 12.7mm 1.2m X 19.1mm 1.2m X 25.4mm Certified to U.S. Mil spec Many Dick Smith Electronics Stores are now being expanded to display our full range of YAESU communications equipment. These stores will have a licensed amateur on site to demonstrate all our product ON AIR! Our stores in Bourke St. Melbourne, Springvale (Melb), York St. Sydney, and Adelaide City store have already been upgraded . Be sure to visit us soon! $2.50 $2.50 $2.95 $2.95 $3.50 $3.50 $3.95 $3.95 $4.50 $4.50 $4.95 $4.95 $6.95 $8.95 $2.00 $2.00 $2.45 $2.45 $3.00 $3.00 $3.50 $3.50 $4.00 $4.00 $4.50 $4.50 $6.25 $8.05 Ideal For Transmitter Wiring! - s& /1 00g roll HPM "TIDY CORD" TEFLON COAXIAL CABLE PACK Coiled lead with IEC line socket and 3-pin plug as used on most electronic RG • 178, 1M LENGTH equipment. Cat W-1 363 Only 2.5mm dia. , this cable can handle up to 100 watts at 500MHz Cat W-2088 s2ss SAVE $1.00 _ ~ · ~' ~ ADCOLA RS30 ADCOLA RS50 ADCOLA RS&O Special offer! ADCOLA DR30 SOLDERING SOLDERING SOLDERING DUOTEMP IRON IRON IRON • Normal plus push-button boost • 16 watt mains powered • Reliable heavy duty element • Long-life Triclad 5mm tip • 12 watt mains powered • Well balanced design • Long-life Triclad 3mm tip Cat T-1825 CatT-1820 • 21 watt mains powered • Lightweight, super-slim barrel • Anti-seize· 6.5mm tip Cat T-1835 temperature settings! • 21 watts on boost • Can be fitted with a variety of specialist tips CatT-1830 Save $5 for this month only Was $39.95 · Was $42.95 2 TIP REPLACEMENT PACKS $1995 To suit ADCOLA irons CatT-1860/2/ 4 s54 .------------------. 5 TIP REPLACEMENT PACKS Was $48.95 To suit ADCOLA irons Cat T-1861/3/5 s4995 SCREWDRIVER SETS SCREWDRIVERS Chrome vanadium blades and insulated handles make these ideal PUSH-ACTION T-BAR for tradesmen , home handymen ... anyone. • 6 & 8mm flat blades MAGNETIC Phillips Head: 95 Head/Shan k Cat No. Price ti~l;r~:~~ ~~s heads s9 SCREWDRIVER 3.2 x 75mm #0 T-6035 $2.95 0 1 : ~ CatT-4~~ 51~2" = ' " ' b ; ~ ~ ~- . • With 6 magnetic bits and plastic holder • 2 Phillips, 2 flat, and 2 Torx bits Reduced MAGNETIC s5ss • Fully insulated with magnetic head • 4.5 & 6mm flat blates • No.1 & 2 Phillips heads • No.1 & 2 Pozidrive heads Cat T-4515 5 x 75mm #1 5 x 100mm. #1 6 x 38mm #2 6 x 100mm #2 6 x 125mm. #2 8 x 150mm #3 T-6037 T-6045 T-6025 T-6047 T-6055 T-6065 $2.95 $3.95 $2.95 $3.95 $3.95 $5.95 T-6028 T-6030 T-6032 $2.50 3.2 x 75mm 4x 100mm 6 x 38mm 6 x 125mm T-6020 T-6052 $2.95 $3.95 from5995 ' Flat Blade: sgss UNIVERSAL CatT-4505 - ~;;;;;;;;;;;,~ · 2 ~ -- BIT SET • For manual or electric drivers 5 BIT SET •4.5 & 7mm flat blades 3.2 x 50mm • Large rubber handle for extra grip • 1.2,6, 6.5&7mmflatbfades • No.1 & 2 Phillips heads : 0 CatT-4500 ~ ~as $9.95 e • No.1 & 2 Phil_lip~ heads • No. 1 & 2 Pozidnve CatT-4518 sass ~<at>~~A ~ <at> IW!l] 5 - ~~,l~~~UiiiQIII Ill ~~rn~== ~ ~g~== 8 x 250mm t~~~~ t~~~~ {!<at>Jl T-6062 $2.95 $2.95 tu~ f~:i~ $5.95 HOBBY NEW! ~~~~~==~ KNIFE SET 3 kni ves in a solid plastic case with mag netic blade holder. Includes 10 blades .. . each a different shape for a different purpose. Cat T-361 8 s159s 3-IN-1 MODULAR TOOL The One Tool That Does It AIII Aprofessional quality Solder Station at a hobbyist's pricer DSE SOLDER STATION • • • • It's a drill plus drill bit It's a Soldering Iron plu It's a Screwdriver plus drivers And it's rechargeable too! cat T-s?12 Unbeatable value at For quick and reliable connections, it beats solder every time! LUG CRIMPING TOOL 0 ~~ : fn~tl~~~i ~!~esof:~~eo~ed lugs • An essential tool in any workshop CatT-3520 $895 . 2 Phillips head screwdrivers 3 Allen key drivers 5 nut drivers 3-5mm 6 flat bladed screwdrivers 1 tommy bar All in a handy plastic case 'HOLDING' SCREWDRIVER SET HOBBYIST TOOL KIT • 5-piece fully insulated screwdriver set • Designed to HOLD screws while being driven • Includes 3 flat blades and 2 Phillips head • 6 Piece jeweller's screwdriver set • 120mm long nose pliers • 110mm side cutters CatT-3294 $2 595 Cat T-4395 t= #tlt=) ~= = = :~:,AA fip 20 PIECE TOOL KIT 5 open ended spanners 4-6mm • • • • • • • • Variable temperature control from 200 to 500 °C • With temperature meter • Lightweight Iron holder plus cleaning sponge Cat T-2000 • ,;;;1,;::::) crU fvr, ; ;; . :;:~;;g:::;.;p s19ss Cat T-4830 s19ss STAINLESS STEEL RULER WITH CUTTING GUARD! Cat T-5146 . . $695 MAGNETIC TOOL HOLDER This 50cm strip simply screws to the wall and holds any shaped metal $995 tools or knives. Cat T-5500 ~45;1?::.· ~ u<at>l..i £UI.I MAJOR DICK SMITH ELECTRONICS AUTHORISED STOCKISTS: N.S.W.: ARMIDALE: New England Electronics 711655 BALLINA: Ballina Electronics 867022 BOWRAL: F.R.H. Electrical in,, 611861 BROKEN HILL: Hobbies & Electronics 884098 COOTAMUNDRA: Cootamundra Music & Lite 422561 COFFS HARBOUR: Coffs Harbour Electronics 525684 DENILIQUIN: Deni Electronics 813672 DUBBO: Chris's Hi Fi 828711 FORSTER: Forster Village Electronics 545006 GLEN INNES: John Sommerlad Electronics 323861 GRAFTON: Repairs and Soares 421911 GRIFFITH: Miatronics 624534 INVERELL: lnverell Electronics 221821 LEETON: Leeton AU<liotronic 532800 LIGHTNING 3 1 1 11~,~~i~;&~ ~~p:;'§.,~fc1:r2M:Nt~~ Nelson Bay Elect & Hobbies 813685 NOWRA: Nowra Electronics 210722 ORANGE: Central West Electronics 626491 PARKES: Strad Music Centre 623366 PORT MACQUARIE: HastiOQS Comfiuter Service 834574 TAREE: Brads Electronics 526603 _ _ _ _ _ _ _ _ _. . . 1 1 1 65 ~~~1:N~6t~ai ?/51Wc~'~: i~rn1~rM~Jii~%'l?~~l=nt~fa1~ MORWELL: Morwell Electronics 346133 SHEPPARTON: Andrew Guyatt Electronics 219497 SWAN HILL: Nvah District TV Service 329303 WARRAGUL: Roylaine 234255 WARRNAMBOOL: Koroit St Elec Services 627417 QLD: AYR: Della Electrix 7 1t½ ~:E:~:bE=n~6~;\c~ fil~t?t~.,,~~l~~~"mA1~R?J:m~H~e7~~=m: 214559 NAMBOUR: Nambour Electronics Shop 411604 PIALBA: Keller Electronics 283749 TAS: BURNIE: Electro!lic City 314760 DEVONPORT: A.I.Electronics 248322 SA: MT GAMBIER: Hutchesson's Communication Centre 250400 PORT LINCOLN: Basshams TV & Comp Wor1d 822788 WHYALLA: Er,e Electronics 454764 WA: ALBANY: Micro Electronics 0 1 ~g;,,7ni~u~~r~~o"R,ij\'.W;~i1~~~GgmlfJ WJ~JJi~ti/T~er~ ET:dt~2t'1RRATHA Da"'5 ~~t~: i::e i~~t{ ~~~~:~~~t~~R~iVi \rl m"b%';,~~ t:i.~ ~~~ t&n :1r e e TIE BOOKS YOU SHOULD BEAD 1990 Edition 1990 Edition 15th Edition ARRL Radio Handbook World Radio TV Handbook ARRL Radio Handbook The bible according to the Amateur Band! The all new hard-back ARRL Handbook is updated with all the latest information for the avid amateur radio operator plus new and innovative projects to build. ~~=========~7 WORLD Cat B-2090 Handlook s35s5 Cat B-2223 s49s5 Comprehensive discussions on principles of virtually al I aspects of antenna design and performance. Contains examples of hundreds of antennas with full construction details. 1990 EDITION Up to date listings of international Radio and TV stations. Provides frequencies, addresses, call signs, IDs, and more! RADIO TV~ Cat B-2208 ELECTRONICS EDUCATION ... THE FUNWAY! Funway 1 Funway 2 Funway 3 Start with the absolute basics and learn to build 20 fascinating projects. The next step. Learn how to solder and use printed· circuits. Another 20 projects to build. Complete these 10 projects and you 'll be able to tackle any of our electronics kits. Cat B-2605 sees Cat B-2600 s4es Electronics Notebook 4 This issue deals with Thyristors, Soldering, using a CRO, Zener diodes, and more. ~====""""""~~ h S695 r.==--= T EL:~i:0":o1~5 Databook Complete listings of all COS/MOS and 74HCOO series ICs Cat B-3637 Cat B-3632 s310 s300 Electronics Notebook 5 Bugging A Preventio Latest in the series. Get the low-down on transistors, resistors, capacitors, and diodes. . '.3" Designs, ideas, and practical information on Bugging and Security. ELECTRONICS NOTEBOOK s Cat B-3640 Cat B-3641 s32s s3as Digital Logic Gates & Flip-Flops Practical Digital Handbook -~~ What they do and how to use them. A great aid to designing and testing digital circuits. Cat B-1271 ' · ·1 An introduction to digital circuits, timers, microprocessors, and digital 1/0 devices. Cat B-1270 Gives you descriptions, equivalents, and pin connections for linear ICs. Cat B-4762 s1ses . ~ --~': . ~. s19ss €.B LINEAR I.C. EQUIVALENTS wu11,1NCONNICTION$ Up-To-Date World ~ Transistor ~ Comparison Table Gives a description and equivalents of every transistor known. Cat B-4760 sgss s19ss Descriptions, equivalents, and pin connections for digital ICs. ,, ~ ' Cat B-5520 Cat B-4761 Digital IC Equivalents Linear Databooks All the important information for the experimenter, technician and project builder. Cat B-2610 Linear IC Equivalents 3 Volume Set €.B International <at>] Diodes Equivalents Equivalents for Zener diodes, Thyristors, Triacs, Diacs, and LEDs. Cat B-4763 s14ss INTERNATIONAL DIODES EQUIVALENTS llNEROIOOn - THYfflT0tt - llHAC$-111,11,CS - LED$ Variable Position Rotary Switches Digital Panel Meter Using the built-in locking device, these switches can be set for anywhere between 2 and their maximum number of positions. • 3.5 digit LCD display • Full Scale of 200mV or 2V into 100M ohms • Auto zeroing & inbuilt overrange • Includes mounting bezel Poles 3 1 4 2 Cat Q-2200 Positions 2-4 2-12 2-3 2-6 Cat No. P-7516 P-7518 P-7520 P-7522 s32s Each s59es Mini Reed Switch Vernier Reduction Drive • Smooth , positive movement for fine control • Suitable for panel mounting • 28mm diametero with inbuilt mounting lugs 25mm long and easily hidden in the wood-work. $135 Cat P-7856 5 DIA. QLAII TUH 0 .,. s15es - "·· ~ ◊ ~ \ . Cat P-7858 41 13 t .• Eli 2.1x0 I j Micro Switches Mini Micro Switches • Activates with only 2-3mm blade movement • Ideal for alarms, safety guards, and limit switch $295 • SPOT contacts cat P-7800 • Just 20x1 Ox6mm • Curved end on actuator arm for cam follower • SPOT contacts $1 75 ~=ri= ~ ~jJ;1ill ~=:r ~ ,.,.Cat P-7802 ~· - ,.,· ' $120 \ i:. j Activating Coil Matching coil for the Mini Reed Switch . The 430ohm coil operates from 6 to 15V DC. ~ ~ • I 2, PCB Mounting Relays 12 volt, 80mA rel ays with fully enclosed contacts. They are ideal for HF, VHF, & UHF switching applications Cat P-8030 • I ~ Cradle Relay Sockets Silver plated sockets to suit 4PDT cradle relays. Cat P-4734 s39s~ Cradle Relays Rated at 12V, 30 watts with 610ms op. time and 3-4ms release time. Cat P-8000 DPDT $1295 • • ,-----------..JL-------------'---- - - - - - - - - - - , DS XPRESS PHONE & MAILORDER SERVICE Outside Sydney (FREE Call) 008 22 6610 Sydney And Enquiries - 888 2105 FAX: (02) 805 1986 or write to DS XPRESS, PO BOX 321 N/RYDE NSW 2113 PHONES SECURITY AUDIO All Major Credit Cards Accepted. 0/Nite Courier Available. 24 HOUR DESPATCH OF ALL ORDERS NSW • Albury 21 8399 • Bankstown Square 707 4888 • Blacktown 671 7722 • Brookvale 905 0441 • Bondi 387 1444 •Campbelltown 27 2199 • Chatswood Chase 4111955 •Chullora 642 8922 •Gore Hill 439 5311 •Gosford 2/i 0235 • Hornsby 477 6633 • Hurstville 580 8622 • Kotara 56 2092 • Liverpool 600 9888 • Maitland 33 7866 • Miranda 525 2722 • Newcastle 611896• North Ryde 8783855 • Parramatta689 2188 • Penrith 32 3400 • Railway Square 211 3777 • Sydney City 267 9111 • Tamworth 66 1711 • Wollongong 28 3800 •ACT• Belcon nen (06) 253 1785 • Fyshwick BO 4944 • VIC • Ballarat 31 5433 • Belmont 43 8522 • Bendigo 43 0388 • Box Hill 890 0699 • Coburg 383 4455 • Dandenong 794 9377 • East Brighton 592 2366 • Essendon 379 7444 • Footscray689 2055 • Franksto n 783 9144 • Geelong 232 711 • MelbournG City 399 Elizabeth St 326 6088 and 246 Bourke St 639 0396 • Richmond 428 1614 • Ringwood 879 5338 • Springvale 547 0522 •OLD• Brisbane City 229 9377 •Buranda 391 6233 • Cairns 311 515 • Chermside 359 6255 • Redbank 288 5599 • Rockhampton 27 9644 • Southport 32 9033 • Toowoomba 38 4300 • Townsvi lle 72 5722 • Underwood 341 0844 • SA •Adelaide City 223 4122 • Beverley 3471900 •Elizabeth 255 6099 •Enfield 260 6088 •St. Marys 277 8977 •WA • Cannington 451 8666 • Fremantle 335 9733 • Perth City 481 3261 • Midland 250 1460 • Northbridge 328 6944 • TAS • Hobart 31 0800 •NT• Stuart Park 81 1977 COMPUTERS " I; (I)~~ j ?I ?f ft ?{IJI ij ;J (IJiJ ~1-'"=oR....o....e....R....e....v __PH_o_N_e_o_uT_s_,o_e_s_v_oN_e_v_<o_os_i_22_e_e1_o_Free_c_a_11s_y_dn_er_A_re_a_aa_a_2_1o_s_ _ _ _ _ ___, The Largest'Australian Electronics Retailer! 63 Stores Across Australia How to make Dynamark labels How do you make professional standard labels for your equipment? The answer is 3M Dynamark. Just about all the labels on the projects P,ublished in SILICON CHIP have Dynamark labels and in this article we tell you how to make them. By LEO SIMPSON Most of the Dynamark labels used on our prototype projects are black on aluminium sheet (0.12mm thick) or black on clear transparency. We generally use aluminium labels on metal boxes and the larger plastic instrument cases and the clear labels on the grey plastic zippy boxes. If we use a black plastic case, the clear labels are inappropriate so again, we use a black aluminium label. So if you have been reading the project articles in SILICON CHIP for some time, you will already know what Dynamark labels look like. If the labels are made from aluminium they will generally have silver lettering on a black background [that's the way we usually make them) or black letters on a silver background. And while we have not featured them in the magazine, Dynamark aluminium labels can also be obtained in red, blue or gold. Also available are Dynamark plastic labels in red/transparent, green/ transparent, black/transparent, blue/transparent, red/white, green/white, black/white, blue/ white, black/silver and black/ gold. The process To make Dynamark labels, you need an actual size artwork (negative) transparency, a source of ultraviolet light [such as a light box with UV fluorescent tubes), a sheet of Dynamark light sensitive material and a bottle of developing fluid. To make the label, all you need do is to expose the Dynamark sheet to ultraviolet light via the transparent artwork. This is usually done in a UV lightbox. The exposure time depends on the light source, the particular Dynamark material and the transparency of the artwork but is generally a few minutes. After exposure, the label material is developed with Dynamark 8500 developer to reproduce the artwork [in reverse). Sunlight In a pinch, you don't even need a UV light source to make Dynamark panels. If it's a bright sunny day, your UV light source comes free, with sunlight. You will need two pieces of plate glass though, to sandwich the transparent artwork and Dynamark sheet. Exposure can be a little trial and error, although we find that 10 to 12 minutes in bright sunlight is enough to expose aluminium labels (Dyn.amark 8003). Normally, though we use a conventional lightbox with UV tubes. Developing These are the main materials for making Dynamark labels: Letrachrome lintfree cotton pads, light sensitive sheets, a bottle of developing fluid and a plastic squeegee. 16 SILICON CHIP Developing the exposed label is a simple matter. Just lay it on a flat surface and pour a small quantity of Dynamark 8500 developer onto it. Spread it evenly over the surface and then after 10 seconds wipe off A light box with UV fluorescent tubes is used to expose the light sensitive sheet via the transparent artwork. This unit from Kalex comes fitted with a 3-range 0-12 minute timer. the exposed emulsion with a lint free cotton pad. By the way, Dynamark 8500 developer should be used in a well ventilated area as it can cause irritation to your nose and eyes. It is also flammable and so should not be used near sparks (welding or electric discharge) or while smoking. Protecting the label To preserve the finished label against scuffs and scratches, we spray it before applying it to the panel with Dynamark clear lacquer which dries in 10 minutes. It is available in matte (3930) or gloss finish (3900). You can also use Estapol Matte or Glossclear lacquer but it takes quite a long time to dry and it tends to pick up dirt while that is happening. For applications where the label is likely to be subject to a lot of dirt and wear, Dynama rk have clear laminating film (8019) which is 'applied to the label before it is affixed to the panel. Cutting to size For cutting and trimming plastic labels to size, you can use scissors, an X-Acto knife, sharp Stanley knife or a paper guillotine. Aluminium labels can be cut with heavy duty scissors, tin snips or a paper guillotine. Cut the edges in one straight action - jagged edges are almost impossible to fix. Fixing the label The label comes with its own pressure sensitive adhesive backing - just tear off the protective paper backing and apply to the panel. This must be done very carefully though, making sure that the label lines up exactly with the panel - once the adhesive grabs, that's it. If you try to pull it off to straighten it up, it will inevitably wrinkle the panel and you'll have to make a new one. Dynamark have a soft squeegee which helps you apply the label evenly and without trapped air bubbles. Reversing the artwork Dynamark is a photogra phic reversal process so that the reproduced label is a negative of the artwork. Since we normally have silver lettering on black with our aluminium panels, we use negative artwork to begin with. However, if you want to reverse that, Dynamark 8007 reversal film is the answer. It is exposed with UV light and developed with 8500 developer as with the label. When using an 8007 reversal transparency to expose a Dynamark label, you must follow the instructions regarding the emulsion side - it is placed next to the label, so that the shiny, non-emulsion side faces the UV light. Step 1 Step 2 Step 3 Other instructions Any other instructions? Yes there are a couple - cleanliness and care, at each stage. At all times, make sure that everything is clean. Both the artwork transparency and material to be exposed must be clean of dust and grease. So should the glass of the lightbox. If you do each step carefully, without charging into it, you can get a very good result - a professional looking panel. You need to be very careful when trimming the finished label to size and then when applying it to the panel. After a little practice though, it is a straightforward process which gives consistently good results. Acknowledgment Our thanks to Ken Laird of Kalex for his assistance in the prepa ration of this article. As well as being a supplier of all the Dynamark range of materials, Kalex can supply Riston printed circuit boa rd Step 4 Step 1: position positive or negative image of artwork (either transparent or translucent) over the Dynamark sheet. Step 2: expose to ultraviolet light. Step 3: apply developer. After 10 seconds, wipe off exposed emulsion with cotton pad. Step 4: trim and add protective coat. Peel adhesive liner, position, and press in place. materials plus a large light box and PCB etching tank. Kalex are at 40 Wallis Avenue, East Ivanhoe, Vic 3079. Phone (03) 497 3422. SEPTEMBER1990 17 Fluke 45 Dual Display Digital Multimeter Fluke's model 45 multimeter is not just an ordinary benchtop instrument - it is a multipurpose instrument that can be used in service workshops, research and development laboratories and production lines. By LEO SIMPSON You know how it is when you are set up to do measurements on a piece of equipment. Say you're measuring an audio source such as a power amplifier. You may want to measure AC output voltage, DC offset voltage, signal frequency, frequency response (in decibels) and so on. Before you know it you have several instruments hooked up to the audio source in question and an unholy mess of test leads. With the Fluke 45 hooked up instead, the test set up is greatly simplified. For example, without changing the connections, you can measure and display the AC output voltage and the signal frequency (anywhere up to 1MHz). Press a few buttons, and the Fluke will display both the power output and the frequency response in decibels. With the test setup still operating, you can boot up your computer and use it to control a series of measurements which can run for as long as you like - an hour, a day, or weeks on end. And you can control the rate at which measurements are recorded and stored on disc, for later recall. The above description gives just a brief insight of what can be done with the Fluke 45 dual display multimeter. We don't propose to cover all the features of the Fluke since it would take more pages than there are in this magazine. In fact, the instruction manual for the unit runs to 120 quarto pages while the manual accompanying the Quickstart 45 software is another 65 pages. So this article really will just amount to a general overview of the instrument. Features As it comes out of the box, the Fluke 45 is a medium size instrument with a light beige coloured case and a contrasting dark Perspex window through which the displays can be seen. It has four recessed jack sockets, the two on the lefthand side being for most measurements while the other two are for current (10 amps and 100mA). In addition, there are 17 touch buttons which control all the meter's functions. On the left, six of the buttons have symbols to indicate Volts DC, Volts AC, Amps DC, Amps AC, Ohms and Diode (Continuity) test. All of these modes are autoranging, which means that the meter automatically selects the range for best reading indication. If you want to lock the meter onto one range, you just push the Auto button; you can then step up or down through the ranges by pushing the Hi or Lo buttons. True RMS measurements How do you get a multimeter to give a reading when no leads are connected? In this case, the Fluke 45 is picking up an internally generated signal at 26kHz. The instrument features a green vacuum fluorescent readout. 18 SILICON CHIP A feature of the Fluke 45 is that it gives true RMS measurements for AC voltages and currents. This is in contrast to the vast majority of meters which are average respon- T~e Fluke 45 is_ shown here con~rolled by an IBM PC (ye~, a genuine true-blue) via the RS-232 interface and Qmckstart software. Both displays are in use on the readout and the measurements are also being recorded on the monitor screen. ding and indicate the RMS value for sinusoidal (ie, sinewave) waveforms only. This means that for all except sinusoidal waveforms, these other meters will always have a reading error. The Fluke doesn't, even for quite complex waveforms. In addition, if the AC volts and DC volts buttons are pressed simultaneously, the Fluke 45 will take a DC measurement and an AC measurement and then display the calculated RMS value. Cancelling lead resistances Ever found that the resistance of your measuring leads caused errors when measuring low resistance values? The Fluke can solve that problem with its RELative mode. Just touch the two leads together and press the REL button. This zeros the display and it can then accurately display the resistance to be measured. Of course, the REL mode is available for all measurement modes and comes in very handy when you have to make a lot of readings to establish trends. Second display The real power of the Fluke 45 is that it has a second 5-digit display which provides every measurement function available on the primary display. The only practical difference is that while the primary display can have auto or manual range selection, the secondary display is autoranging only. Because the second display duplicates all the functions of the primary display, it effectively is two 5-digit multimeters in one. Sample rates Often measurements can be made inaccurate by the amount of noise superimposed on the lines being measured. The Fluke can help overcome that too by varying the rate at which the measurements are made, at 2.5, 5 or 20 readings per second. The rate is shown on the display with an "S" (slow), ''M" (medium) or "F" (fast). Varying the rate to get rid of noise and jitter on measurements does have a down side though because it varies the resolution. Maximum resolution is obtained at the slowest sample rate. At the slow setting, maximum resolution is 100,000 count (ie, 5 digits); at the medium ·setting, maximum resolution is 30,000 count while at the fast setting it is 3000 count, equivalent to typical 3 ½-digit meters. Accuracy Resolution is not to be confused with accuracy, of course, and as continued on page 117 SEPTEMBER 1990 19 The Bose Lifestyle™ Music System The end of conventional hifi systems? By LEO SIMPSON For quite a few years now, more or less since the advent of the compact disc player, the design of hifi systems has been pretty static. Whether large or small, they have always seemed complicated to the uninitiated and even to those familiar with them. Now that has all changed, with the coming of the Bose Lifestyle Music System. Not only have hifi systems always had lots of controls, for the last 15 years or so they have been ugly black monoliths. And the loudspeakers have been big, or small, black rectangles. No wonder most women don't like hifi systems , even though most like music. Let's face it, most hifi systems are ugly monstrosities. They don't blend with rooms, they dominate them. Now there is the Bose Lifestyle Musi c System, a system that doesn't look like a hifi system at all. In fa ct, it doesn't look like any electronic appliance previously available. As our pictures show, it is a slim polished aluminium case. It opens to reveal a compact disc player and an AM/FM stereo tuner. Having no knobs at all, it is meant to be controlled by the remote handpiece. An RF device rather than using infrared light, it works from anywhere in the home or outside it, with a range of about 30 metres from the music centre. Nor do the loudspeakers look like loudspeakers. They are so small and insignificant that they can be virtually invisible or even completely hidden in most rooms. Yet the loudspeaker system is driven by Is this what you'll be listening to in the future? This is the complete Bose system, to suit two listening zones. The Acoustimass powered woofer and "twiddlers" serve one area while the smaller Roommate-styled speakers would serve another room. 20 SILICON CHIP amplifiers with a total power of 200 watts - loud enough for anyone but seeming to come almost out of thin air. Hifi without controls So this is the Bose Music System, a highly flexible system but lacking many of the controls we have come to expect on hifi systems . For example, there are no tone controls, no loudness switch, no balance control, no source and mode selector switches, no fancy flashing lights - not even a volume control knob. And what about the speakers? How can they get away with such insignificant little stacked cubes? And for that matter, how do they cram 200 watts of power amplifiers into the music centre? They don't. The speakers are a powered version of the Bose Acoustimass 5 this is a satellite cum superwoofer system. We've already stated that the system is meant to be controlled by the remote handpiece but even there it does not have any user facilities for adjusting the tone (bass , treble or loudness) or balance. Instead, the Bose system incorporates automatic loudness compensation, continuously adjusting the bass response according to the sound level. As well, there are preset bass and treble controls on the Acoustimass enclosure. These are set and forget controls which are not meant to be used in everyday listening. In practice, they would be set when the system was installed and then not touched. Twiddlers The satellite speakers are the little stacked cubes. Because they can be angled to alter the sound dispersion and because they handle mostly treble, Bose calls them "twiddlers''. They handle all the signal Spot the speakers in this room. They're up behind the greenery on the room divider. That's the beauty of the Bose system which allows the speakers to be completely concealed if you want. above about 200Hz and are driven by 50 watt per channel amplifiers. The Acoustimass superwoofer is Bose 's double tuned resonant system active equalised and fed by a 100 watt amplifier. The 50 watt amplifiers and 100 watt amplifier are all in the woofer box and it can be hidden almost anywhere in the room. All the sound seems to emanate from the twiddlers, provided you can spot them, and that creates a dramatic impression, especially to anyone familiar with conventional loudspeakers. Different zones A big drawback of current hifi systems is that they only allow one source to be used at one time. So if SEPTEMB EH1990 21 The Bose Music System is intended to be fully integrated with video systems. In this photo, the Bose "twiddlers" are visible but not obtrusive. the compact disc player is being used, the tuner or tape deck can't play. With the Bose system, not only is it possible to listen to two program sources at one time, it is possi- ble to listen to them in different parts of the house. For example, you could listen to the compact disc player in the lounge room while someone else could listen to the AM/FM tuner or watch a video in another part of the house. Both sources in the music centre can be separately controlled with separate or the same RF remote handpiece. This is possible because the Bose system uses powered loudspeakers, either the Acoustimass system already referred to , or smaller powered Bose Roommate style speakers. Any number of powered loudspeakers can be run from the music system, although with two program Bose's remote control can be used from any part of the house or even outside. An RF device, it controls all the facilities on the Music Centre. 22 SILICON CHIP zones, only two program sources can be listened to at one time. Besides the inbuilt compact disc player and tuner, the Bose music system has phono sockets for tape monitor loop, auxiliary and video stereo inputs. The source that most people will note is missing is a conventional turntable. That can still be used but it means connecting a conventional hifi system to the music centre via the auxiliary inputs. First impressions We first saw the Bose Music System at the Australian release on July 19th. Everyone who saw the system came away impressed with the concept. It will radically change hifi systems as we have come to know them. No longer will people be willing to accept a large wall unit or a rack of hifi equipment in their listening rooms. They will not want to look at the gear - it will have to be virtually invisible. So that's the concept of the radical new Bose system. People will love it and it is sure to be imitated on a wide scale by other manufacturers. But is it hifi? You will have to wait till the next continued on page 121 wpoo FOR CHIPS ... WOOD FOR CHIPS ... WOOD FOR CHIPS ... WOOD FiOR CHIPS ... WOOD FOR CHIPS ... WOOD FOR CHIPS ... WOOD FOR Analog Panel Meters Now stocking Rack Cases & Frames We carry a wide range of analog meters for projects, instruments etc. If you have a requirement not listed ask and we'll locate something suitable. • SEW meter movements • Not susceptible to stray fields • High precision jewel and pwot suspensions ~ G Q: 0 I.I.. Cl 0 ~ ~ G Q: 0 I.I.. Cl 0 ~ ·70x60mm 71x34mm 48x48mm 3.5mm hole 1Q1-. 20, 30Vdc, 3wVac Current: 50, ±50, 100, ±100µAdc 1, ±1, 100mAdc 1,±5b10,20,30Adc 10, 2 , 30Aac Specify range required when ordering $16.80 Model ST-45 Dimensions: 51x51mm Scale: 51x31mm Bolt centres: 38x38mm 3.5mm hole Ranges: Voltage: 1~20, 30Vdc, 3wVac Current: 50, ±50, 100, ±100µAdc 1,±1, 100mAdc 1,5,±5, 10,20,30Adc 10, 20,30Aac Specify range required when ordering $15 .80 Model ST-65 Dimensions: Scale: Bolt centres: Ranges: Voltage: ~ :i:(J Q: 0 I.I.. Cl 0 ~ 67x67mm 66x38.5mm 51x51mm 3.5mm hole 1Q1.20, 30Vdc, 3wVac Current: 50, ±50, 100, ±100µAdc 1, ±1, 100mAdc 1,5, 10,20,30Adc 10, 20,_30Aac Specify range required when ordering $17 .40 Model ST-38 Dimensions: Scale: Bolt centres: Ranges: Voltage: 45x45mm 44x25min 31x31mm 3.5mm hole 1Q1-. 20, 30Vdc, 3wVac Current: 1OOµAdc, \ 50mAdc 1OAdc, 10Aac Specify range required when ~ ordering $15.20 ·· Model ST-160 ~ G Q: 0 I.I.. Cl 0 ~ ~ G Q: Aluminium construction with removable top and bottom steel covers Conforms to International S t a n d a r d s ~ Natural or Black anodised finish Ventilated lids Assemble yourself in minutes Panel Casa Cat No Price Hai~ht Hole Space He ight Depth Width Natural Black 44 1RU! 34 38 254 430 H0401 H0411 $59.95 88 2RU 57 82 254 430 H0402 H0412 $79.95 132 (3R ) 89 38 254 430 H0403 H0413 $89.95 Blank Panels to Sult Model ST-670 Dimensions: Scale: Bolt centres: Ranges: Voltage: • • • • • VU Indicator Back Light Built In 650'1 Internal Resistance Bezel Mounting 120x94mm $23.80 Haight 44 (1RUi 88 (2RU 132 (3R ) Natural H0421 $12.50 H0422 $16.50 H0423 $21.90 Black Anodised H0426 $13 .60 H0427 $24.50 H0428 $29.95 Black Powdercoat H0434 $12.50 H0435 $19 .50 H0436 $24.50 Economy Rack Cabinet • Solid steel construction • Black anodised front panel • 132mm (3RU) standard size • Ventilated top and side panels Only $69.95 High Energy 3RU Rack Case • Ideal for Amplifiers, Power Supplies, Chargers etc • Built-In Heatsink Side Panels • Up to 120WAudio Output Stages accomodated each side • Easy.installation of cooling fans ~ • Internal dimensions 125x370x250mm ~ ~ - __ -'5,;§;;;, • External dimensions 130x440x252mm • Choice of Grey or Black Powdercoat Front Panel $119.95 re, ~ o· .,, t, Seriallest serial data analysis on your PC This is an MS-DOS software and cabling package which enables technicians and engineers to perform serial data comms analysis. It offers sophisticated problem solving facilities at a fraction of the cost of dedicated hardware systems. SerialTest provides a window onto RS232 lines operating either as a passive observer or actively sending data or control signals to simulate either at DTE or DCE device. Triggers can be defined based on error conditions or data to initiate or terminate monitoring sequences. 0 JJ 2 ~ ~ 0 t, Ideal For Professional Users or Home Stereos etc Six sizes - 4 6, 12, 18, 30 and 38RU Snaps together in minutes- no skill required Push fit and then align with rubber hammer Available with or without side panels Each pack contains 12 custom extruded _natural anodised aluminium . sections, 8 ABS corner connectors, 6 cftp-m capttve nuts and 6 mountmg screws • Side and Top panels in powdercoat blue GRU Size 4RU Height 280mm 370mm H0365 Frame H0362 Price $139.00 $149.00 Panel H0363 H0367 Price $49 .00 $55.00 Accessories Rack Screws Natural Rack Screws Black Rack Captive Nuts Nylon Washers 30RU 38RU 12RU 18RU 630mm 900mm 1430mm 1790mm H0375 H0380 H0368 H0370 $169 .00 $189.00 $229.00 $269.DD H0369 H0372 H03TT H0382 $89.00 $110.DD $159 .DO $195 .DO 12 pack 100 pack H0385 $2.95 H0386 $19 .95 H0391 $19.95 H0390 $2.95 H0396 $45.50 H0395 $5.95 H0399 $ 8.50 H0398 $1.50 Model ST-70W Cross Needle Meter Three Meters In One • Measures Volts, Current & Power • Ideal for Communications Equipment and Mobile Use • Measures 70x70mm DC RMges 0-30V 0-5A 0-SOW 0-30V' 0-1 SA 0-250W 0-30v: 0-30A: 0-500W Specify range required when ordering $34.80 ii DIC-5000 Desoldering Tool The SC-5000 gun incorporates a motorised diaphragm pump. There are no tubes or separate compressors. A built-in thermosensor circuit controls the GOW ceramic heater to ensure ra·pid warm-up. Exact temperature control prevents damage to sensitive circuitry. The gun can also be used as a hot blow tool. $399.00 ex tax ($479 .50 inc tax) Optional Stand $42.50 • Handles baud rates up to 115.2kbaud . • View each byte in ASCII or EBCDIC, decoded to hex, decimal, binary or octal • Writes captured data directly to disk to allow maximum capture buffer • CRC checksum calculations • Auto-configuration to any of the comms ports 1 to 4 • Time-stamping (absolute and relative) including delta time calculations • Split line DTE over DCE display $395 plus sales tax Send $10 for a demo disk, refundable on purchase. ULTRASONIC CLEANER The latest nign-tech way to clean PCB's, switches, watches, drafting pens - even your dentures! Let the millions of !my cavitation bubbles clean the surface 40000 times per second. 165x90x50mm container holds half a litre and is made of 304 stainless steel. Some people are charging $200. Cur's are only $160. ~ 0 t, .,, 0 JJ ":i: ~ ~0 .,,t, 0 JJ ":i: ~ ~ GEOFF WOOD ELECTRONICS PTY LTD 0 t, 229 Burns Bay Road , (Corner Beatrice St.) tNC tN Nsw Lane Cove West, N.S.W. P.O. Box 671 , Lane Cove N.S.W. 2066 0 JJ Telephone: , (02) 428 4111 Fax: (02) 428 5198. 8.30am to 5.00pm Monday to Friday, 8.30am to 12 noon Saturday. Mai l Orders add $_5.00to cover postal charges. Next day delivery in Sydney add $5.00. 0 Total flexibility at very modest cost. And this month only- the two way models are both $39.00. You save up to $16.00!! 2 Way Serial (RS232) $39.00 Parallel (Centronics)$39.DD 4 Way Serial (RS232) $70 .00 Parallel (Centronics)$80.DD Rack Frames 0 ~ Save on Manual Data Switches • • • • • • Cl I.I.. ,c Prices shown in brackets are sales tax exempt .,, " :i: ~ i w~ ~ BA~ Tax-exemption certificates accepted if line value exceeds $10.00. BANKCARD, MASTERCARD, VISA, CHEQUES OR CASH CHEERFULLY ACCEPTED Remote Control Extender For VCRs There's no need to buy a second VCR for the bedroom. This simple project will allow you to operate your VCR using its remote control from any room in the house. By JOHN CLARKE & GREG SWAIN Many families now have two colour TV sets, one usually located in the living room with a VCR and the other in one of the bedrooms. While it's easy to link both TV sets to the VCR (via a splitter), controlling the VCR when you want to watch a video in bed is a problem. Until now, the only way to control the VCR has been for you to get out of bed and go into the living room so that the remote control can be . operated. That's a real nuisance, especially if you want to fast forward over adverts or access any of the VCR's other controls. But now that problem has been solved with our new Infrared Remote Control Extender. It will let you control the VCR from your bedroom using the existing remote control. Basically, the project consists of a receiver that picks up the signal from your remote control. This signal is then converted to an electrical signal and sent down a VCR. Fig.1 shows the basic scheme. Of course, the extender is not only limited to VCRs - it can relay any IR-transmitted signal. Typically, the extender sits next to your TV set and will have a range of 10-15 metres, depending on the output from your remote control. The unit uses inexpensive parts, does not require any special shielding, and is easy to build and install. How it works Refer now to Fig.2 which shows the circuit schematic. There are just two ICs involved, plus a Darlington transistor, a photodiode, an infrared LED and a few other bits. ICl is a Plessey SL486 Infrared Remote Control Preamplifier which is specifically designed for processing received infrared control signals. This device features a differential photodiode input to re- The circuit is housed in a plastic case which is smaller than the remote control. A LED at one end flashes when you activate the remote control to indicate that the signal is being received. 2-wire cable to an infrared LED located near the VCR in the living room. Thus, when you operate your remote control, the IR LED in the living room flashes with the correct code sequence and activates the 24 SILICON CHIP duce noise pickup and an automatic gain control circuit for improved operation in noisy environments. It also incorporates two gyrator circuits and these allow the device to operate in high ambient light conditions. ROOM 2 ~-□ SECONO TV \\ MAIN TV Pulse extender a VCR REMOTE ,_.CONTROL ROOM 1 Fig.1: a typical set-up. The IR extender picks up infrared light from the VCR's remote control and converts it to an electrical signal. This signal is then sent down a 2-wire cable and drives an IR LED located in the same room as the VCR. The incoming IR signals from the remote control are picked up by photodiode D1 (BPW50). This is connected across the differential inputs of IC1 which converts the IR pulses to electrical pulses. These pulses are then amplified and filtered by ICl, with the output pulse train appearing at pin 9. In operation, pin 9 is normally at ground potential but swings high each time a pulse is received from the remote control transmitter. The capacitors on pins 2, 3, 5, 6 and 15 of IC1 roll off the frequency to control the gain of the first three amplifier stages. Schmitt trigger inverters IC2a and IC2b square up the signal from IC1 and drive paralleled inverter stages IC2c, IC2d and IC2e. These in turn drive the base of Darlington transistor Ql via a lkO resistor. Each time a pulse of infrared light is received, Ql turns on and pulses the infrared LED (IRLED 1) via a 4.70 resistor. responses of the gyrator and gain stages below 2kHz. This filters out any 100Hz and 50Hz signals which are generated by mains powered lights and picked up by the photodiode. If this was not done, these noise signals would seriously degrade the receiver's sensitivity and reduce its effective range. Automatic gain control (AGC) is provided by an internal peak detector which measures the output at pin 9. A 0.15µ,F capacitor on pin 8 filters the output of the peak detector and the resultin~ signal is used LED 1 and its associated circuit provide a visible indication that a signal has been received. LED 1 cannot be directly driven by Q1 because this transistor is only pulsed on for very short periods of time. To overcome this problem, a simple pulse extender circuit is used. Each time Ql turns on, the .033µ,F capacitor on pin 3 of IC2f charges via D2. When it reaches a critical level, pin 4 of IC2f switches low and LED 1 turns on. The 100kn resistor discharges the .033µ,F capacitor when the pulses from Q1 cease. Thus, depending on the code from the transmitter, LED 1 will flicker on and off but at a much slower rate than the pulse frequency applied to IRLED 1. Power for the circuit is derived from a 9V DC plugpack which feeds a 7808 3-terminal regular. This provides a fixed + 8V supply rail which is filtered by a 470µ,F capacitor. A 470 resistor and 22µ,F capacitor provide further supply .....--------41.,..._---.........,._______,470W J ~ - - - -.....- - - - - - > - - - - - - - - - - - - - - + 8 V 6.8 16VW 47 _ 16VW + + 470 + 10VW! .0047 _ .033 RECEIVER ACKNOWLEDGE LED1 RED . IC2b 74C14 , 40106 A a, B0682 IC1 SL486 01 BPW50 RECEIVER AMPLIFIER PULSE SQUARER ANO DRIVER .,. +v-------11.........., +BV 9V DC PLUG-PACK -+ m""' ~PLASTIC TRANSMITTER EICl8 IR REMOTE CONTROL EXTENDER r lR LIGHT ACTIVE SIDE K A Fig.2: each time an IR light pulse is received, pin 9 of IC1 switches high. This then drives Ql and IRLED 1 via Schmitt trigger inverters IC2a-IC2e. · SEPTEMBER1990 25 CAPACITOR CODES Value 0.15µF .033µF .015µF .0047µF 56pF LED 1 and Dl are both mounted at full lead length and then bent over so that they fit into holes in the end of the case. It is also necessary to bend the 7808 regulator over slightly to clear the lid. line decoupling for !Cl to prevent false triggering. Construction Most of the parts are mounted on a small PC board coded SC 15108901 (50 x 44mm). Fig.3 shows the parts layout diagram. Begin the assembly by installing PC stakes at points 1 and 2 and at the plus and minus terminals for the power supply leads. Next, install the wire link, followed by the resistors and capacitors. Note that the 470µF capacitor is laid on its side and its leads bent at right angles to pass through the holes on the PCB. Take care with the polarity of the electrolytic capacitors. Diode D2 and the two !Cs can now be mounted. Check the orientation of the two !Cs carefully, as they face in opposite directions. The infrared LED (IRLED 1) is mounted at the end of the 2-wire cable. It can be mounted in a small case or taped in some inconspicuous location near the VCR. The next step is to mount Ql and the 7808 regulator. Push these components down into the board as far as they will comfortably go before soldering their leads. Ql is installed with its metal face towards the 470µF capacitor while the metal IEC Code 100n 33n 15n 4n7 56p EIA Code 154 333 153 472 56 tab of the 7808 goes towards the adjacent lOµF capacitor (see pinout diagrams on Fig.2}. Bend the 7808 over slightly so that its tab does not later foul the lid of the case. LED 1 and Dl are mounted with full length leads so that they can later be bent over to protrude through the side of the project box. Be sure to orient these devices correctly. In each case, the anode (A) lead is the longer of the two. The completed PCB can now be fitted inside the case and used as a template for marking the mounting hole positions. Drill these holes to accept the mounting screws (3mm), then temporarily mount the board in the case on 6mm standoffs and mark out the holes for LED 1 and Dl. Once this has been done, remove the board and drill the hole for LED 1, plus additional holes in the other end of the case to accept the power socket and the rubber grommet. To make the cutout for Dl, first drill a pilot hole, then use a needlepoint file to square up the hole so that the photodiode fits neatly into it. All that remains now is the final assembly. Refit the PCB, install the socket and grommet, and complete the external wiring as shown in Fig.3. You will have to bend the leads of LED 1 and Dl so that these components fit the holes drilled in the case (see photograph). Before soldering the power supply leads to the PCB, it is a good idea TABLE 1: RESISTOR COLOUR CODES □ □ □ □ □ □ 26 No 1 1 1 1 1 SILICON CHIP Value 100k0 1k0 4700 470 4.70 4-Band Code (5%) brown black yellow gold brown black red gold yellow violet brown gold yellow violet black gold yellow violet gold gold 5-Band Code (1%) brown black black orange brown brown black black brown brown yellow violet black black brown yellow violet black gold brown yellow violet black silver brown PARTS LIST 1 ,, l~~K 2---:-0 - - A t TO IRLED1 \ CQY89 RUBBER GROMMET Fig.3: here's how to wire up the IR extender. Take care with component orientation and note that the two ICs face in opposite directions. Check the polarity of the power supply leads using a multimeter before soldering them to the PC board. Testing This view shows how the photodiode (Dt) and the acknowledge LED (LED 1) are mounted. Make the holes so that both components are a tight fit. to connect the plugpack supply and check their polarity with a multimeter. Once you have identified the leads, they can then be soldered to the PC board. The IR LED is connected to the receiver via a long length of light-duty speaker cable. This LED can be either mounted in a separate small case or taped tn some inconspicuous location near the VCR. To test the circuit, apply power and check for + 8V on pin 14 of ICZ. If this is OK, activate the remote control and check that the acknowledge LED flickers. You should be able to do this out to a range of about 10 metres, depending on your remote control. Make sure that light from IRLED 1 cannot reach the receiver during this test procedure, otherwise the receiver will be desensitised. The unit can now be tested with your VCR. You should be able to get a range of at least 4 metres between the VCR and IRLED 1, although this will depend on the sensitivity of the VCR's IR receiver. If need be, the range can be increased by adding a second IR LED in series with IRLED 1. Finally, keep the receiver away from the TV set. If you place it too close, line flyback pulses from the TV can find their way into the receiver's circuitry and degrade the sensitivity. ~ 1 1 4 4 4 plastic case, 54 x 83 x 30mm PCB, code SC15108901, 50 x 44mm front panel label, 80 x 50mm 6mm ID rubber grommet 6mm PCB standoffs screws & nuts for standoffs small rubber feet Semiconductors 1 SL486 IR preamplifier (IC1) 1 40106, 7 4C14 hex CMOS Schmitt trigger (IC2) 1 B0682 PNP Darlington transistor (01) 1 7808 3-terminal 8V regulator 1 BPW50 or equivalent IR photodiode (D1) 1 1 N914, 1 N4148 signal diode (D2) 1 CQY89, LD271 IR LED (IRLED 1) 1 5mm red LED (LED 1 ) Capacitors 1 4 70µF 1 OVW PC electrolytic 1 4 7 µF 16VW PC electrolytic 1 22µF 16VW PC electrolytic 1 1 OµF 25VW PC electrolytic 1 6.8µF 16VW PC electrolytic 1 0.15µF metallised polyester 2 .033µF metallised polyester 1 .015µF metallised polyester 1 .004 7µF metallised polyester 1 56pF ceramic Resistors (0.25W, 5%) 1 1 OOkO 1 470 1 1k0 1 4.70 1 4700 Miscellaneous Twin wire for IR LED, small plastic box for IR LED if required, solder, etc. F Figs.4 & 5: here are actual size artworks for the PC board and the front panel. _:J SEPTEMBER 1990 27 S V (ALL PRICES PER BOX OF 10·0tSKS) 0 Now you can buy sbsofute top quality dlUs that are al so the cheapest In Austral lal They ev en come with a lllallme warranty, which Indica tes the quatlty of th e,e dltks. 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Mode selection : Black and while lone, halftone Is selected by operating the mode selclor switch Graduations : 32 graduations Can be adjusted by the density Density: control VR · EXTRA FEATURES • IMAGE FILE APPLICATION • DESKTOP PUBLISHING APPLICATION • FAX TRANSMISSION APPLICATION • DR. HALO DPE SOFTWARE INCLUDED. The Story Of Electrical Energy, Pt.3 Alternators can be regarded as the central machines in power stations. They convert the mechanical energy of the turbines into electrical energy. To do so, alternators require very heavy excitation currents and advanced methods of cooling to keep the internal heat generated under control. By BRYAN MAHER As we noted in the first episode of this series, an alternator has two sets of windings: the stator or stationary windings in which the huge voltages and currents are generated, and the rotor which provides the rotating magnetic field. It is the interaction of this field with the stator windings that produces the 30 SILICON CHIP electrical output. The magnetic flux density is very strong, typically 2 to 2.5 Teslas. This is more than twice the flux density present in the voice coil gap of modern loudspeakers which have very large permanent magnets. In big alternators, the magnetic field is produced by very large DC currents fed to heavy coils of silverbearing hard-drawn copper wound on the rotor. These "excitation" currents are usually fed to the coils of the spinning rotor via carbon brushes which run on two large sliprings mounted on (but insulated from) the main shaft. Exciting currents In earlier systems, excitation currents were usually provided by DC · generators driven by the main turbine shaft. Alternatively, in some installations the exciter was driven by a separate small steam turbine. The field coils of the exciting generator were usually supplied by a smaller DC generator called the pilot exciter, as shown in Fig.1. This practice gave good control of the excitation voltage but DC LEFT: THE 500 MEGAWATT turboalternators at Wallerawang power station, NSW are hydrogen and water cooled. In the background is the steam turbine of one unit and in front of it, the main alternator. The large rectangular housing in front of the main alternator is the main exciter. In the foreground are the pilot and starting . exciters. PILOT EXCITER OC GENERA TOR MAIN EXCITER DC GENERATOR COMMUTATOR ~ ARMATURE COMMUTATOR SOFT CARBON __, BRUSHES VOLTAGE REGULATOR generators with commutators require considerable maintenance. 3</> HIGH VOLTAGE 50Hz OUTPUT Modern exciters To eliminate the need for any commutators, modern systems have small alternators to generate an auxiliary AC supply. This is fed to silicon rectifiers to provide the DC excitation for the rotor of the main alternator. Fig.2 is a block diagram of the excitation system controlling one of the 500MW alternators at Wallerawang power station. Fig.2 shows a steam turbine (A) driving the main 500MW alternator (B). This has its exciting currents provided by the main exciter (E). This is a 2.6 megawatt 3-phase alternator which feeds a bridge rectifier (D) consisting of multiple silicon diodes. The bridge rectifier's DC output is fed to the rotor of the 500MW alternator by the sliprings (C). Since the main exciter is also an alternator, it must have its rotor supplied by DC currents. These are supplied by the 90kW pilot exciter (H). It too. is an alternator but it is EXCITATION STARTER GENERATOR (K) MAIN AL TERNA TOR FIG.1: THIS IS THE CLASSIC METHOD of excitation as used in olde1· alternators. A DC generator is used to generate the current for the rotor field of the main alternator. This exciter is then controlled by the pilot exciter which is another DC generator. This has the advantage of being easy to control but DC generators require lots of maintenance to their brushes commutators and sliprings. rather unusual. As shown in Fig.2, its DC field coils are mounted on the stator while the AC output is taken from the rotor. This may seem a little weird but electrically, it is immaterial whether the DC field or the AC output winding rotates. So the pilot exciter is an "inverted" alternator. The pilot exciter's 3-phase output is taken from the triple sliprings (J) and then goes to two rectifiers (G & M). M is a small silicon diode bridge supplying the stationary DC fields of the pilot exciter (H). G is a much larger thyristor bridge which supplies a variable DC voltage (up to 74V and 160 amps) to the rotor field coils of the main exciter E, via sliprings (F). Voltage regulation Just as the alternator in a car needs to have a voltage regulator, so that the car's electrics and battery will not be damaged, then so too the very large alternators in our power stations. If they didn't have voltage regulation, the mains voltage would vary enormously according to the load. In Fig.2, voltage regulation is provided by the thyristor bridge rectifier G. It controls the variable output of the pilot exciter and therefore controls the output of the main exciter alternator. And since the main exciter directly controls the field windings of the main alternator, the thyristor bridge G 90kW 3<b PILOT EXCITER (H) (LI 2.6MW MAIN EXCITER (E) AC 500MW MAIN AL TERNA TOR (B) MAIN EXCITER SLIP-RINGS (F) 3000RPM STEAM TURBINE (A) SPEED GOVERNOR 235VAC 220A 100Hz 3.,; ~"7""-j--1 74V 160A 420V 3850A 100Hz 3o , AC (G) VOLTAGE REGULATOR (0) FULL-WAVE RECTIFIER OUTPUT 500MW 22kV l15437A 3</> 50Hz FIG.2: THIS IS THE METHOD OF FIELD excitation used more commonly today. In fact, this is the block diagram for the 500MW alternators at Wallerawang power station, NSW. The main exciter is an alternator and it is controlled by a pilot exciter which is an "inverted" alternator - its output is taken from the rotor rather than the stator. SEPTEMBER1990 31 MAIN EXCITER (E) PILOT EXCITER (H) MAIN ALTERNATOR (B) MAIN SHAFT '-c:-=_=_ :::::1--l AC CABLES INSIDE HOLLOW MAIN SHAFT FIELD COILS (G) oc 3Q 400Hz (Al MAIN SHAFT 1 ..,_ 1 ~:i.~.1.~J WINrii~lll VO LTAGE REGU LATOR 400Hz AC currents generated in its stator are rectified and controlled by a 6-tpyristor full wave bridge (G). (In a 3-phase bridge rectifier, s ix diodes or thyristors are required). The direct currents so derived energise the stator field coils of the main exciter (E). This is an inverted alternator wherein AC currents of a few thousand amps are generated in its rotor coils. Heavy cables, running inside the hollow shaft, carry these large alternating currents to a a silicon diode bridge located within a wheel (X) mounted on the shaft. The resulting rectified DC flows via copper conductors through the shaft to the rotor windings of the 300MW alternator (B). So the rotor field windings are excited without any brushes or sliprings being used. Having no brushes anywhere considerably reduces maintenance and makes for more compact, lighter machines. Each turbo-alternator weighs only 700 tonnes. The 300 megawatt output of each machine is conducted by 500mm diameter hollow aluminium busbars to the alternator transformers outside the building in the station switchyard. Here the voltage is stepped up to 275kV for transmission to Brisbane, the Gold Coast, Kareeya (near Cairns in the deep north) and all points on Queensland's east coast. STEAM TU RBINE DIODE WHEEL (X) 16.2kV 12.6kA 285/JOOMW FIG. 3: MORE MODERN SYSTEMS, such as the Gladstone power station in Queensland, use an excitation system which is completely free of brushes, commutators or sliprings. Note the use of the diode wheel to rectify the main exciter's output before it is fed to the rotor of the main alternator. therefore controls the output of the whole system. G is called the Automatic Voltage Regulator (or A VR) of the complete turboalternator. citer via rectifier fL). As the voltage generated by the pilot exciter builds up, it begins to supply its own fields through rectifier M. Starting excitation Brushless excitation We have seen how the main alternator has its field coils driven by the main exciter which in turn is controlled by the pilot exciter. Well, the pilot exciter is an alternator too and you guessed it, it has it own exciter, called the excitation starter . This is a small 12-pole 300Hz permanent magnet generator. When the turbines are being run up to speed, it supplies the auxiliary DC field coils on the pilot ex- A particularly interesting excitation method is used at Gladstone power station in Queensland. Here each of the six 300MW turboalternators is excited by a completely brushless system. No sliprings, brushes or commutators are used. Fig.3 shows this clever scheme. The pilot exciter (H) in this case is a 3-phase 16-pole alternator with a permanent magnet rotor. The Synchronising alternators VIEW INSIDE THE TURBINE HALL of Gladstone power station, in the far north of Queensland. The 285MW alternators are all hydrogen cooled. 32 SILICON C I-IIP Most power stations have a number of alternators running and sharing the load. Also the electricity grid system links all power stations in the state together. This means that all the alternators in the state's power grid are effectively connected in parallel. As you might imagine, connecting and running dozens of alternators together in a system grid is not simple task. lil order to connect all the alternators in parallel, five requirements must be met. All machines must: (1). Generate the same voltage; (2). Run at exactly the same speed; (3). Generate the same frequency; (4). Produce a pure sinewave voltage waveform; and BIG ALTERNATORS REQUIRE big on/off switches. This set of 3-phase circuit breakers can break a current of 250,000 amps. Each breaker measures approximately 4 metres long and 3 metres high. (5). Must be in phase with each other (ie, the generated sinewave must rise and fall with exactly the same timing in all machines). This last requirement is called synchronisation. Starting an alternator When an additional alternator is to be connected into the system, the normal procedure for starting is as follows: (1). Steam is applied to the turbine to bring it very gradually up to temperature and full speed. This takes many hours because of the large thermal mass of the machine and the very high operating temperature. While the machine is coming up to operating temperature, it is not electrically connected to the system (ie, the alternator circuit breaker is not yet closed). l2). A synchroscope is used to measure the phase difference between the voltage generated by the incoming machine and that of the state grid system. (3). If the measurements reveal any difference in phase timing, the in- coming machine must be speeded up or slowed (more or less steam applied). Usually only slight changes are needed but the phase correspondence with the other system alternators must be exact. (4). When synchronism is achieved and held for a stabilising period, then and only then is the alternator circuit breaker closed. The new machine is now connected in parallel with the system but as yet is carrying no load. (5). After perhaps an hour or more of unloaded running for temperature equilibrium, the incoming alternator is made to supply some share of the system electrical load. The total time for this procedure for a large alternator of, say, 500 megawatts, is around 8 hours. For this reason, alternators are usually kept running all the time, whether or not they are supplying power to the system. In this way, they make up the "spinning reserve" of the system. Load sharing To make a synchronised alter- nator supply a greater share of the system load, more steam is admitted to the turbine. It is not done by increasing the alternator's output voltage, as you might expect. No, increasing the excitation of one machine running in parallel with many others would not raise its voltage nor increase its power load share. More excitation would only cause that alternator to supply a larger portion of the out-of-phase component of the state load. Feeding more steam to the turbine makes it push harder against the mechanical braking effect of the electrical power load on the alternator. That alternator then takes a greater share of the system power load. Excitation must then be increased to compensate for the demagnetising effect that the stator reaction has on the rotor field. We can explain this process of load sharing by using an analogy. Consider 15 people pushing a car up a steep hill. The pushers correspond to all the parallel alternators in the power system. The effort needed to propel the car may be likened to the state's electrical power load. All these volunteers grab the car and move with it. They are all 'in sync'. If you make a move to help, you may walk with the car in perfect synchronism, yet do no work. To take a greater share of the load, what must you do? You walk at the same speed but just push harder! You have turned on more steam! If for any reason one alternator in a system should lose steam supply and attempt to slow down, that machine no longer carries any load. Rather, the rest of the system alter~ators will force it to stay in sync; ie, at full speed. The errant alternator is said to be "motoring" on the system. Obviously this is not the way a steam power station normally runs as it constitutes an extra load on the rest of the alternators. It would normally never happen. Faulty synchronisation Should an alternator be running too slow when the circuit breaker is closed to join it to the state electricity grid, all hell would break loose! Very large currents would inSEPTEMBER 1990 33 turbo-alternators of ever greater capacity are being installed worldwide. But they can't just get bigger and bigger. Severe constraints exist in the size and weight of alternators that can be transported from the manufacturers' plants to power station sites. For this reason, ongoing development must produce alternators of higher power rating without much increase in mass and dimensions. This demands greater current density in windings and stronger magnetic fields to generate more volts per turn. But more amps per square cm of conductor means that more heat is generated and therefore more effective cooling methods must be devised. Means of cooling THIS PHOTO, TAKEN DURING the construction of a 500 megawatt alternator, shows the teflon pipes which carry the de-ionised water to cool the stator windings. Teflon plumbing and de-ionised water must be used because the stator winding operates at thousands of volts above the machine's frame. Note the heavy bracing which secures the stator windings. stantly flow. Enormous power would surge into the slower machine from the others in an effort to pull it into synchronism. With a hundred or so tonnes rotating at 3000rpm in each alternator, even a small speed alteration translates into enormous momentum and kinetic energy changes. Huge mechanical shock waves would reverberate within each unit from its stator core to the foundations. For these reasons, great care must be taken in ensuring that each alternator is exactly synchronised before it is connected to the system. Circuit breakers From time to time, faults and short circuits do occur in the statewide electricity grid systems. When this happens, enormous fault currents can flow during the time 34 SILICON CHIP taken for the circuit breakers to open. For this reason, faster, stronger and bigger switches are constantly being developed, especially for alternator circuit breaker service. One of the photos included in this article shows the alternator circuit breaker units installed at Meppen power station, Germany. Each these circuit breakers, made by Brown Boveri et Cie, measures around 4 metres long and 3 metres high and is capable of interrupting fault currents of up to 250,000 amps in 50 milliseconds. That's some switch! Power density The demand for electrical energy increases exponentially with the years - around 5 % per annum in industrialised countries. Therefore, With alternators rated up to 60 megawatts or so, air cooling is used. In the basement below the machine are mounted large motordriven centrifugal fans which blow filtered fresh air at high speed through the alternator, to cool the stator and rotor windings. But for bigger alternators, air cooling just can't do the job. For these machines, hydrogen cooling is used. Pure hydrogen gas at around eight times atmospheric pressure is circulated through passageways in the stator and rotor cores. Thus, the windings are indirectly cooled. But hydrogen is highly inflammable and can form dangerously explosive mixtures with air, so what about the safety aspect? Because the hydrogen in the alternator is at a pressure well above the outside air, any leakage will be of hydrogen leaking out, not air leaking in. So the possibility of an explosive mixture is very low. And, of course, the outer casing of the alternators is fitted with hydrogen detectors to warn of any potential hazards. But why use a dangerous gas like hydrogen anyhow? Hydrogen gas is used as a coolant because it is much lighter than air and because it has much greater specific heat. Because hydrogen is so much lighter than air, even when at eight times atmospheric pressure, alternators spinning in a hydrogen at- THIS IS A SECTION cut from an alternator's stator coil. It is wound using multiple flat copper tubes through which water is circulated for cooling. Each flat tube is about 9 x 4mm. The outside insulation is 8mm thick and consists of a mica/glass/epoxy resin material. mosphere have greatly reduced windage losses. And because hydrogen has 14 times greater specific heat and eight times better thermal conductivity than air, it can collect and carry the heat away from alternator windings very efficiently. because each winding is running at tens of thousands of volts above ground! Now you can see why deionised or distilled water is used if ordinary water were used, it would be a short circuit at these high voltages. Water cooled stators Under normal load, the stator current applies a mechanical braking torque against the rotation of the rotor. The steam turbine does work by pushing against this force. But every action implies an equal and opposite reaction from the stationary component; ie, the stator coil itself. Therefore, the winding continuously experiences a sideways For alternators of 350 megawatt to 1.5 gigawatt capacity, even more cooling is required. So in addition to the hydrogen cooling just described, the stator windings are water cooled. Instead of using solid copper conductors, the stator windings are wound from flat copper tubes. Each turn of the winding terminates in a manifold and deionised water is pumped from grounded pipes through teflon hoses to the manifolds. The teflon hoses are absolutely necessary Winding forces force of up to 12 tonnes, and this squeezes the stator copper bars against their insulation and the core slot walls. The insulating materials used must be mechanically strong enough at running temperature to withstand these forces. However, much more violent forces are possible within an alternator, when faults occur. As noted above, short circuits can occur in the state grid system due to lightning strikes or accidents. The excessive currents then flowing in the alternator stator conductors can produce enormous destructive forces on the windings. To prevent the coils from being torn apart, large steel clamps are provided. These are bolted solidly to the frame as illustrated in one of the photos accompanying this article. Next month, we'll have a look at the high voltage power lines used transmit the power to the end users. Acknowledgements Special thanks for photos and data to the Electricity Commissions of NSW and Queensland, the management and staff of Wallerawang Power Station, ABB and ASEA Reviews, Electronics and Power, and C. A. Parsons Ltd. ~ THIS PHOTO OF A LARGE AL TERNATOR rotor shows the fans which help circulate the cooling hydrogen. The hydrogen circulates through passages in both the rotor and stator to cool the windings indirectly. SEPTEMBER 1990 35 _,_ LECTRONICS,CSJAYCAR ELECTRONICS LECTRONICS,CSJAYCAR ELECTRONICS LECTRONICS,CSJAYCAR ELE.;TRONICS LECTRONICS,CSJAYCAR ELECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONICS LECTRONIC LECTRONICS LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONICS LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONICS LECTRONICS LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC LECTRONIC 'LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC UCTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC 'LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC :LECTRONIC JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRON ICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR Jaycar, in conjunction with Altronics Perth, have pooled resources to buy the entire stock of DTX Australia Ltd 'Directronics' brand Videotex (VIATEL) terminals. These terminals enable you to connect your phone (some models even have phones supplied!). TV or RGB colour monitor to set up a VIATEL system in your home of office! Just think, you can access all of that fantastic information on VIATEL without having to pay a fortune for an expensive terminal. You will still need to pay the VIATEL service fee of course!! Each videotex terminal contains a fully Telecom approved modem and all electronics to decode VIATEL signals and display them on your TV or RGB monitor. We have roughly the same quantities of 4 fairly similar models. Model #1 .... ••• .... a•• (the cheapest) features full console, numeric keypad (for entering into and operating the Videotex system). RF out (to your TV) but no phone. You can plug any phone into the socket provided of course. The phone is only used to . access the Videotex Note: this a picture of Model #2 number anyway (some phones can be used as key pads however). This machine is all you really need. Cat. YV-707s$29.95 That's right under $30 - HURRY, HURRY, HURRY!! Customers have been disappointed before when we have run out. Make sure you get in quick so that you won't be disappointed. Quantities are strictly limited but once sold, they are gone forever! $34.95 This is one of the greatest bargains we have ever seen!! $34.95 Info on VIATEL Model #4 - as per model #3 but with a phone as well. $39.95 NOTE! All models are brand new in cartons with instructions. They are worth far more than this for the parts alone. They contain valuable Philips SAA5020 and 5050 chips. Because we are selling these at such a ridiculously low cost warranty is only one month from receipt. If you are worried about this buy a model #1 as a spare! I I I I I I Worth around $250 less than a few years ago. Model #3 - as per model #1 but with RF and RGB video output (for better quality colour on a suitable RGB colour monitor). Cat. YV-7078 ~--~ ___ .. ·-· ELECTRONIC! ELECTRONIC! ELECTRONIC! ELECTRO, You will never be able to get into VIATEL this cheap ever again. phone which can be used as a keypad. Cat. YV-7077 ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR SENSATION! Model #2 - identical to above but with a dedicated Cat. YV-7076 ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR TheVIATEL service has been renamed Discovery 40 or Discovery 80 depending on the level of service you require. Access fee is $65 per year. Once you subscribe to the service you will get a PIN number which will access you into the system. For more information call 'Discovery 80' (part of Telecom) on 008 033 344 illlli ELECTRONll ELECTRON! l ! l l l l ELECTRONIC ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR I ELECTRONICSJAYCAR ELECTRONICSJAYCAA =rFTCTRiCll'JTT ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRQNICSJAYCAB ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR El ECIBONICSJAYCAB ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR El ECTRONIGSJAYCAREU:_C:TAnNll.S IAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR CS, CS, ELECTRONICS ELECTRONICS, ELECTRONICS ELECTRONICS, FI FCTAOI\IICS !AYCAP FI FCIPObllCC: 1AYC.6D i:;:u;c T □ arn c ~ .,..,. , ...,,...,,, LLL,._,, 1"1\.Jl'IIV.., ..,,, , ....r" < ................ I,,,._, , ,.,...,...,.,_,,..,.,....,,..,,,\ LI...L..,._,, ,v._., , ,.,....,-.>,../M1 ,._,,..,,,, ............ ..... 1 n\.,11'1 1\..,v,,Jf-\ ,vnn l:..LC::\., I nVl'IIVUVM l\.,Mn CLCV I nvt'll l l...,.::>..J/-\TL,Mti CLC\.., lt1V l',I IL,.::,.JATL,l-\t1 t:.LCl., I HUl\ll\,..,;::,.JI-\YL,AH t.Lt.L I t1 IAYCAA ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTR AYCAR ELECTRONICS JAYCAR ELECTAONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTR AYCAA ELECTRONICS JAYCAA ELECTAONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTAONICSJAYCAR ELECTH ·- · · --- · ·- · ;:mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm; Thromatic♦ NEW BOOKS FOR 1990 Security Sensor Everyday Elec tronics Data Book by Mike Tooley This book is an invaluable source of information of everyday relevance in the world of electronics. It contains not only sections which deal with the essential theory of electronic circuits. but it also deals with a wide range of practical electronic applications. It is ideal for the hobbyist, student, technician and engineer. The information is presented in the form of a basic electronic recipe book with numerous examples showing how theory can be put into practice using a range of commonly available 'industry standard' components and devices. A must for everyone involved in electronics. 250 pages 140 x 215mm Cat BP-1222 \ This great product utilises a passive infra red detector which controls 240V lights to illuminate at night when a person comes within range, A typical example would be on a verandah. Sjmply replace the old light switch Ioutside one) with the Thromatic. When someone walks within range lup to 15mt away) the verandah is lit up for them for a period of 5 seconds to 10 minutes. or more. Features: • Fully automatic compact design • Security - keep intruders away • On/Off/Auto master switch on unit • Safety - no more groping in the dark Suitable for entrances, porches. patios. stairways. garages, basements. hallways. closets, attics. storerooms, warehouses, workshops etc. Up until now this type of product has been around $100 or more. Jaycar has now di rectly sourced this prcxluct. which effectively cuts out the middle man saving you money. \. ______ , ••• ONLY $69.S0sAVE $30 over previous models $19.95 Cat. 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AYCAA ELE ~ JAYCAR ELE• Ideal for Hobbyists, experimenters. etc. IJAYCAR ELE Tobuythese todaytheywouldcostabout$13ea. Y JAYCAR ELE IJAYCAR ELE JAYCAR ELE Cat. SB-2470 JAYCAR ELE JAYCAR ELE !CAR ELECTAONICSJAYCAR ELECTRONICSJAYCAR ELECTAONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICS ELECTRONICSJAYCAR ELEClJAYCAR ELE !CAR ELECTRONICSJAVCAR ELECTRONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTAONICSJAYCAR ELECTRONICSJAVCAR ELECTRONICS ELECTRONICSJAYCAR ELEC'JAYCAR ELE !CAR ELECTRONICSJAYCAR ELECTRONICSJAVCAR ELECTRONICSJAYCAR ELECTAONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS: ELECTRONICSJAYCAR ELEC'JAYCAR ELE !CAR ELECTRONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICS: ELECTRONICSJAYCAR ELEC.JAYCAR ELE !CAA ELECTRONICSJAYCAR ELECTAONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAVCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICS: ELECTRONICSJAYCAR ELEC.JAYCAR ELE !CAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAA ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICS: ELECTAONICSJAYCAR ELEC.JA VCAR ELE• Fax-Phone Modem Line Protector Elect ronic Power Supply Handbook ~ /1 ~ 1'(7\ •v·~( · v ~~ $19.95 How To Set Up A Home Recording Studio $99 .QQ ~eieieieieiei Panel Cutter !JI I 19.95 \..,$16.95 r·· 12V DC Fan l $24.9. VARTA BATTERY MADNESS NOW$79.95 l0 ONLY $1 each 90;. h +• eaC 100+ •75C each I l,C.AD Cl Cl"'TQCIIIICC IA Y r>AO l:"I Cf"'TDf"\t.llf"'C' IAVr/1.0 Cl CrT □ f"\.h.~A.)lC"A O Cl Cl""TDr\ h.lU"' C' I AVC A O Cl C C TO O II/I C .... IA VC AD Cl Cl'."'T□ f"'l--tlr'C' I A~.L'.': :!:O C l CCTOOll' C"C"! l C l r r--rn,.-..,.,,,...~ ,.t. vc A □ C l e r ·~ -- · .... ,...,.- ,;.:JJM TVI-\M CLCV I t,Ul'llV,::,.Jf-\ T VI-\M. CLCV I MUl'llV~I-\ f\..,1-\11 CLC\.., I MUl'IIV.::,.JI-\ TVl-\n CLC V I M V l 'I IV..:>.JM. T \..,t'\I., CLCV I MUl'lll\..,.:>Jf-\ TVJ-\M CLCV I MUl'llV.:>Vf-\ TL,f-\M t:.U.:L, I HUNll.,;::) JAYL,AH t:Lt: L, l HUNIL.JAYCAR ELEC.J ;sJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICJAYCAR ELECT ;SJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRON!CSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICJAYCAR ELECT ,... .. ......... ................... .... WCAR ELECT WCAR ELECT \YCAR ELECT \YCAR ELECT Ref: Silicon Chip August 1990 WCAR ELECT This new Digital Sine/Square Wave Generator uses high speed CMOS and a digital filter IC to produce sine and square waves WCAR ELECT over a very wide frequency range - from 0.1 Hz to 500kHz. \YCAR ELECT Specifications: \YCAR ELECT • Frequency Range: 0.1 Hz to 500kHz in four ranges - 0.1Hz to 10Hz, 10Hz to 1000Hz, 1kHz to lOOkHz and lOOkHz to 500kHz. • \YCAR ELECT Output Waveforms: Sine and Square• Harmonic Distortion: Less than 0.1 % from 0.1 Hz to 50kHz, 0.27% at 80kHz • Square \YCAR ELECT \YCAR ELECT Wave Rise Time: 10ns • Square Wave \YCAR ELECT Fail Time: 10ns • Output Level: Sine wave \YCAR ELECT variable from 0-1.2Vrms; Square wave \YCAR ELECT variable from Oto 5V p-p • Output \YCAR ELECT Impedance: 600 ohm nominal • Load \YCAR ELECT Impedance 600 ohm to infinity • Protection: \YCAR ELECT Short circuit protected (indefinite)• Display \YCAR ELECT Ref: Slicon Chip August 1990 Accuracy: (pm) 2% (ps) 1 digit \YCAR ELECT Horis is a great project that is fun to use once you've built it. \YCAR ELECT The Jaycar kit includes PCB, box, punched \YCAR ELECT Horis can sit anywhere and when he hears a sound he will and screen front panel and all specified \YCAR ELECT chirp back. Haris is small and can easily be hidden. components. \YCAR ELECT Kit includes PCB, mic insert and all specified components. Cat. KC-5079 \YCAR ELECT Cat. KC-50BO \YCAR ELECT \YCAR ELECT \YCAR ELECT \YCAR ELECT IYCAR ELECT \YCAR ELECT \YCAR ELECT \YCAR ELECT Ret. EA May 1990 IYCAR ELECT Ref: Silicon Chip April '90 1YCAR ELECT This kit features high efficiency toroid power transformer, professional high resolution 10Replace those expensive 9V batteries with an economical 1.5V D cell. lasts much longer and \YCAR ELECT turn wire wound voltage control potentiometer, latest I.C. technology, excellent line load saves you the cost of the kit in no time. Shortform kit - PCB, potcores, battery holder, heatsink 1YCAR ELECT regulation, low ripple voltage, apart from a smart plastic case! (for more information see and all electronic components supplied (excluding optional receiver parts). No box or box specs below). \YCAR ELECT hardware supplied. 1YCAR ELECT The Jaycar kit is complete down to the last nut and screw as well as all hard-to-get I.C.'s. 1YCAR ELECT Cat. KA-1724 CatNo. KC-5073 1YCAR ELECT 1YCAR ELECT 1YCAR ELECT \YCAR ELECT 1YCAR ELECT 1YCAR ELECT 1YCAR ELECT ,YCAR ELECT 1YCAR ELECT 1YCAR ELECT 1YCAR ELECT 1YCAR ELECT ,YCAR ELECT ,YCAR ELECT ,YCAR ELECT Refer silicon Chip May 90 ,YCAR ELECT Refer EA July 1990 Designed for cars with Reluctor distributors, ,YCAR ELECT Measures RF volts, power SWR and impedance well this ignition kit features impr0,1ed protection ,YCAR ELECT into the UHF region. The Jaycar kit is shortform - all ,YCAR ELECT for the coil and main switching transistor. specified components EXCEPT the diecast case, bracket, ,YCAR ELECT Kit includes PCB, die cast box and all labels etc. The box Cat HB-5016 is available for $25.95 ,YCAR ELECT components to finish the kit Kit (shortform) ,YCAR ELECT ,YCAR ELECT KC-5076 ,YCAR ELECT SINE/SQUARE WAVE GENERATOR $179.50 The Cricket e I $16.95 VOLTUP KIT A 1 .5 to 9V DC/DC converter ± SOY (0-1 00V) 1.SA Dual Tracking Power Supply Kit 229 ONLY $19.95 High Energy lgn Reluctor Distrib $39.95 $46.95 ~-------------:::==~~::::::::______ Low Noise Universal 1pF · 9999uF Capacitance Meter Kit , < ( ]'YCAR ELECT ,YCAR ELECT ,YCAR ELECT .YCAR ELECT ,YCAR ELECTI .YCAR ELECTI Refer Silicon Chip May 90 ,YCAR ELECTI Refer Silicon Chip June 90 ,YCAR ELECTI This attractive 4 digit capacitance meter Ideal for a magnetic cartridge, tape player or ,YCAR ELECT! kit is designed for workshop, laboratory or microphones. Shortform kit, includes PCB switch, ,YCAR ELECT! serious hobbyists. It can measure cable and all electronic components. ,YCAR ELECT! capacitance from 1pf up to 9999uf in 1YCAR ELECT! No box front panel or panel hardware supplied. seven ranges with an accuracy of better ,YCAR ELECT! Cat KC-5077 than+/- 1% +/- 1 digit. Kit is complete .YCAR ELECT! with all components required to ,YCAR ELECTI ,YCAR ELECT! finish construction. . ,YCAR ELECT! ,YCAR ELECT! ,YCAR ELECT! MAIL ORDERS POST .. PACKING MAIL ORDER VIA ,YCAR ELECT! 8 37 ,YCAR ELECT! 1 ,YCAR ELECT! ~ ~dConcord2137 $10-$24.99 $ 3.75 1YCAR ELECT! Telephone (02) 747 2022 FOR ORDERS ONLY $25-$49.99 $ 4.50 ROAD FREIGHT ANYWHERE ,YCAR ELECT! FACSIMILE (02) 744 0767 TOLLFREE (008) 022 888 $50- $99.99 $ 6.50 IN AUSTRALIA (up to2llkg) ,YCAR ELECT! ; 1 ----------~=========~o:'..:'.v.:.'.ER.!.:$~100~--~$8~.~oo'....!::===3=· ,YCAR ELECT! ,YCAR ELECT! GORE HILL 188 Pacific Hwy (Cnr. Bellevue Ave) (02) 439 4799,YCAR ELECTI 9 4 5 30 9 SYDNEY - CITY 117 York St. (02) 2671614- Mon-Fri - . Sat - pm ,YCAR ELECT! Mon-Fri 8.30 _5.30 Thurs 8.30 pm_ Sat 9 _12 BURANDA QLD 144 Logan Rd (07) 393 0777 ,YCAR ELECTI Mon-Fri 9 - 5.30 Thurs 8.30 - Sat 9 - 12 ,YCAR ELECTI PARRAMATTA 355 Church St (Cnr. Victoria Rd) (02 )683 '3377 MELBOURNE-CITY Shop 2, 45 A'Beckett St City (03) 663 2030 ,YCAR ELECT! Mon-Fri 9 - 5.30 Thurs 8.30 pm - Sat 9- 4pm Mon-Fri 9 _5.30 Fri 8.30- Sat 9- 12 .YCAR ELECT! 115 Parramatta Rd (02) 745 3077 CONCORD ,YCAR ELECTI Mon-Fri 8.30. 5.30- Sat 8.30 - 12 SPRINGVALE VIC 887-889 Springvale Road Mulgrave (03) 547 1022 .YCAR ELECTI Forest Rd _ Nr Cnr. Dandenong Road Mon-Fri 9 - 5.30 Fri 8.30 - Sat 9 - 2 121 .YCAR ELECT! HURSlVILLE 1021570 7000 Mon-Frig_ 5.30Thurs B.30 pm. Sat9-4 ADELAIDE S.A. 190Wright Street (Cnr Selby Street) (08) 231 7355 ELECT! . ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _9_ __ __ _9_ _ _ _ _ _ _ _ _. . YCAR YCARELECTI Mon-Fri - 5.30 Fri 8.30 - Sat - 12 YCAR ELECTf ;:;, $32.95 • ~~~~~ ~2C~~~o;~:~ ' ~• ~ , ~~~~a~;ia 'a' ==== H B VISA iAYCAR ELECTnONICSJAYCAR JAYCAR ELECTRONICSJAYCAR JAYCAR ELECTRONICSJAYCAR JAYCAR ELECTRONICSJAYCAR JAYCAR ELECTRONICSJAYCAR JAYCAR ELECTRONICSJAYCAR JAYCAR ELECTRONICSJAYCAR I ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECfRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRON!CSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRO NICS JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTI ELECTRON!CSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTI Music on hold for your telephone How many times have you just sat down to a meal and the telephone rings? Annoying, isn't it? This little project won't solve that problem but it will allow the person on the other end to at least wait with music on the line, until you finish your meal. By JEFF MONEGAL & BRANCO JUSTIC Seriously, how often do you have to put the phone down during a conversation to go and get something? Or maybe you've had to discuss something with someone in your household while the caller "hangs on" 40 SILICON CHIP With this project, you can put the incoming caller on hold with music. When a call comes in and you have to put the phone down for a while, just press the ON button and hang up the phone. The unit will hold the line and send music to the other end. After about 5 minutes, if you have not come back to the phone, it will automatically hang up. In use, the unit connects in parallel with the existing phone and does not interfere with normal phone operation in any way. The music can be from any convenient source and an on-board power switch is provided to power it up when needed. The prototype used a small Walkman-style radio. How it works The complete circuit is shown in Fig.1. We'll begin the description with the "line siezing" section centred around the RS flipflop consisting of IC2a and IC2b. This controls a number of transistors in the +12V I T10. 220pF II-- M•r LYBUZZER 39k i ~-r'" 1M 01 BC327 r- -B 0.1 o--r 47k 02 1N914 -i '"'H '-.1./ 0.47 AUDIO INPUT i T 4-, 39kt 01 1N914 I 03 1N914 ..,. 10 "'-t' ..J.: + B~ 02 BC337 --·-i 330pF .__ .,. 1k I RADIO POWER SUPPLY + ~ T I I ...L. -i 33k TO RADIO V+ 47+ .,. 0.1 010 1N914 PHONE LINE 0.1+ + 07 BC548 EOc ON .,. c0E :ll ..... co co 0 0 B It 14 CLKIC3 4024 AST ~ 100k 1M 100k j1K t s21 OFF 0 IC2d 1 .,. C t:'1 ::: .,. MPSA42 >-'J b:l t:'1 .,. S1 LED1 BC C/J .,. IC2a 4093 100k E B t:'1 "O 100! .00331 39k -:+ 10? D13 1N914 VIEWED FROM BELOW MUSIC-ON-HOLD ii>, I-" Fig.1: the circuit siezes the phone line and switches on the radio when you press the ON button. .,. Fig.2: you can install the parts on the PCB in any order you like but be sure to use the correct part at each location. Use PC stakes to terminate external wiring leads. ;fJ 1 2 ~ □11 ~ rl1igi'i~~~®® .l~ - Ll]J :<at>~ l ~ ®~ I 04 ~ 10 ~ 0 1Q ~ ~ ~ oou{;:) 1 07 [J E:} • c,, ~0• • 88.® "' I0,._®~:,:® ® m L!} ~ ~ TORADIOV+ TO RADIO POWER SUPPLY 05 ~ 01 ~~ ~~ .[Jo,. ~ ~ -· 010 o--c:::D-4 □12 01~ . o 18 ~~ ~ ,.,;:; !.! o ~ t□i =i oo?~ l;Jo6~ ~ ~ TT oOM:J[v' 01 a _\ \ . " "" 02 ®~~ ~ [!,,'7 □2 01 ~ ~ ~ {.-1 ~ s;,J o[J[}, 275L40B 4 ~ 7 u F10uF ~ -c:=n---ru:o,. .----i, - .... r;§ 1GzD e • ~ P HONE 0 +• DJ 220pF~ 1 LINE AUDIO INPUT + ®o[illJe ~ ~ □1 ~7k 0.1 ,.,i-_;_-i 12V circuit. When the hold button, S1, is pressed, pin 3 of IC2a goes high. This turns on Q6 and connects Q7 to the phone line via the diode bridge (D6-D9). Q7 functions as a constant current load for the phone line and thus "holds" the line. LED 1 provides a reference voltage of about 1.7 volts to the base of Q7 and it therefore feeds a constant voltage of about 1V to the 4711 emitter resistor. By this means, Q7 draws a more or less constant current of around 21 milliamps from the phone line. Once Q7 is on, the phone handset can be placed back on the hook and the line will be on hold. When Q6 switches on, it feeds a positive pulse to the reset input (pin 2) of counter IC3 via diode Dl 1 and the 0.1µ,F capacitor. This allows the counter to start counting pulses from Schmitt trigger oscillator, IC2c. Oscillator IC2c and counter IC3 are there for two reasons: (1) to stop you from forgetting that you have left the phone on hold; or (2) if you do forget, to take the line off hold so that you can receive the next incoming call. Let's see how. this happens. As well as providing clock pulses to counter IC3, IC2c turns Q3 on briefly, every two seconds or so. This causes LED 2 to flash briefly and the piezo buzzer, connected via transformer Tl, to click. Thus, Q3 gives an audible and visible indication that the phone is on hold. At the same time, counter IC3 is clocked by IC2c until, after 128 pulses, pin 3 (Q7) goes high. This causes pin 11 of IC2d to go low and reset the RS flipflop via diode D13. This turns off Q6 and Q7 to discon- RESISTOR CODES □ □ □ □ □ □ □ □ □ □ □ 42 No. 3 1 4 3 5 1 1 7 1 1 2 SILICON CH IP Value 1 OMO 1 Mn 1OOkfl 47k11 39k11 33k11 4 . 7k11 1 kfl 10011 4711 2211 4-Band Code brown black blue gold brown black green gold brown black yellow gold yellow violet orange gold orange white orange gold orange orange orange gold yellow violet red gold brown black red gold brown black brown gold yellow violet black gold red red black gold 5-Band Code brown black black green brown brown black black yellow brown brown black black orange brown yellow violet black red brown orange white black red brown orange orange black red brown yellow violet black brown brown brown black black brown brown brown black black black brown yellow violet black gold brown red red black black gold brown CAPACITOR CODES· Value D D D D D D IEC Code 470n 0.47µF 0.1µF 100n .01µF 1 On .0033µF 3n3 330p 330pF 220p 220pF EIA Code 474K 104K 103K 332K 331K 221K nect the line. So the period for which the unit will "hold" the line is about 4½ to 5 minutes, depending on circuit tolerances. Audio section The audio section of the project is centered around ICl, a TL072 dual FET-input op amp. ICla acts as a variable gain stage. It is fed with the audio signal from an external battery-powered radio. The audio signal is ideally taken from a portable (such as a Walkman-style radio) which has a headphone socket. This makes it easy to disconnect the radio for any reason. The gain of ICla can be varied between one (unity) and 22 by the gain control preset pot, VRl. ICla then feeds IClb, Ql and Q2. These are set up as an audio power amplifier to drive the phone line via a 0.47 µF capacitor, a lkQ resistor and the diode bridge, D6-D9. Radio supply switch As noted above, a batterypowered radio (or portable tape player) provides the music signal. To conserve the batteries, the radio only needs to be turned on while the phone is on hold. This can be achieved by placing a pair of switch wires in series with one of the cells in the battery holder. We'll tell you how to do this later. The two switch wires go to PNP transistor Q5 - positive ( + ) to emitter, negative ( - ) to collector. Q5 is an AD162 PNP germanium power transistor, a type now obsolete but still available from some sources. A germanium transistor is used as the switch because when it is saturated (ie, fully turned on), it has a very low voltage drop from emitter to collector. Q5 is turned on by Q4, a PNP silicon transistor driven by pin 4 of IC2b. Q4 is on when pin 4 of IC2b The PCB is mounted on the lid of the case and flying leads run directly to the DC plugpack, the radio and the telephone plug. Alternatively, the power supply, audio and radio supply switch leads can be terminated in sockets mounted on the rear panel. goes low, a complementary condition of pin 3 of IC2a going high. Thus, whenever the RS flipflop (IC2a & IC2b) turns on Q6 and Q7, to place the phone on hold, it also turns on Q4 and Q5 to power up the radio. Power Power for the circuit is provided by an external 12V DC plugpack. Very little current is drawn by the circuit when it is not active. The CMOS ICs (ie, IC2 & IC3) draw very little power anyway and ICl and its associated audio output stage is effectively choked off when the input to ICl (pin 2) is pulled low by IC2a, via diode Dl. Finally, a few words about phone line voltages. The normal DC voltage across phone lines when the phone is "off hook" is about 50 volts. The 25Hz ring voltage is about 70 volts RMS, superimposed on the 50 volts DC already there. This means that the maximum voltage that has to be withstood by Q6 is around 160 volts. This it can do quite happily since it is a 300 volt transistor. Even so, to provide a degree of protection for Q6, a 275V varistor is connected across the output of the diode bridge. Construction All the circuitry for this project is accommodated on a printed circuit board measuring 75 x 132mm. It is mounted on the lid of a plastic jiffy box measuring 159 x 96 x 52mm. Holes are drilled on one side of the case to take the two pushbutton switches and the two light emitting Where to buy the kit A kit of parts for this project is available for $44.90 plus $4 .00 postage and packing from Oatley Electronics, PO Box 89, Oatley, NSW 2223 . Phone (02) 579 4985. The kit does not includes the Telecom male plug, parallel adaptor socket, or 12V DC plugpack. The 12V plugpack is available for an additional $ 1 4 .90. Note : copyright of the PCB artwork associated with this project is retained by Oatley Electronics. SEPTEMBER 1990 43 MNS/t: on via screws and nuts and star washers. Watch the polarity and orientation of the diodes, transistors and integrated circuits. Sockets are recommended for the integrated circuits as they are a real problem if they have to be removed later on. Once the PCB has been assembled, carefully inspect all your work. IIOLD Wiring There is quite a lot of wiring to run inside the case to the printed board. The two wires to the phone line must go to pins 2 and 6 of a standard Telecom male phone plug. Polarity is not important as the bridge rectifier (D6-D9) takes care of that. Testing Keep the wiring tidy by lacing it at regular intervals with plastic cable ties. We used sockets for the ICs but these are optional. The audio input lead should be run using shielded cable to prevent hum pickup. A small Walkman-style radio can be used to provide the music. All you have to do is plug the Music On Hold unit into the headphone socket. Don't forget to wire the plug for mono operation. diodes. Adhesive rubber feet are fitted to the lid of the case so that the box effectively sits upside down when in normal use. Assembling the printed circuit board is fairly straightforward although there are one or two points that need comment. The small audio transformer is secured to the printed board by two lugs 44 SILICO N CHIP which are bent over and soldered on the copper side. The four leads are then soldered to their respective pads on the board. The AD162 is a TO-66 metal case device with its collector connected to case. It is mounted right down onto the board and the base and emitter leads soldered to the board. The collector (case) connection is made Do not connect the unit to the phone line at this stage. Connect a 12V DC plugpack or power supply and connect an audio signal. If you have an oscilloscope, you should find the signal present at the junction of the 220 emitter resistors for Ql and Q2. If no audio signal is present, check all the circuitry associated with ICl. If you don't have an oscilloscope, you can still check that ICl is functioning by listening with a pair of headphones (the higher the impedance the better) via the 0.4 7µF capacitor at the output of the audio stage. The sound will be tinny but that is a consequence of the relatively small coupling capacitor. Press the ON button (Sl). LED 2 should flash and clicking should be heard from the piezo buzzer. Pushing button S2 will stop LED 2 from flashing and the piezo buzzer should cease clicking. Now press button Sl and check that LED 2 stops flashing after about 4 or 5 minutes. So far, so good. Radio switch Earlier on we mentioned connecting a pair of switch wires in series with one of the cells in the radio's battery holder. The way this is done is quite simple. All you need is a small piece of double sided copper laminate; it should measure about 3 to 5mm wide by about 10mm long. One switch wire is soldered to each side of the copper laminate. Use a red wire for the positive connection PARTS LIST 1 PCB, code OE 90 MOH, 75 x 132mm 1 small audio transformer 1 piezo disc buzzer 1 Telecom male telephone plug 1 Telecom parallel adaptor socket 1 plastic jiffy box, 1 59 x 96 x 55mm 3.5mm stereo jack plug (to suit headphone socket of Walkman-style radio) 2 momentary contact pushbutton switches 1 12V DC plugpack Semiconductors 1 TL072 , TL082 FET-input op amp (IC1) 1 4093 quad 2-input Schmitt NAND gate (IC2) 1 4024 7-stage counter (IC3) 1 BC327 NPN transistor (01) 1 BC337 PNP transistor (02) 2 BC559 PNP transistors (03,04) 1 AD162 germanium PNP transistor (05) 1 MPSA42 NPN high voltage transistor (06) 1 BC548 NPN transistor (07) and a black wire for the negative connection. The copper laminate is then pushed into the battery holder where it will be held in place by the positive connection of one of the cells. The side with the red wire soldered to it should go against the positive battery terminal. If the wires are not connected, the radio should not work. Then, when both This close-up view shows the wiring to the LEDs and pushbutton switches. The varistor can be installed either way around. 8 1 N914, 1 N4148 silicon diodes (D1 -D3, D5, D11-D13) 5 1 N4004 silicon power diodes (D4 ,D6 ,D7 ,D8,D9) 2 5mm red LEDs (LED1, LED2) 1 275L408 275VAC varistor Capacitors 1 1OOµF 16VW PC electrolytic 2 1 OµF 16VW PC electrolytic 1 4. 7µF 16VW PC electrolytic 1 0 .4 7 µF 1 OOVW metallised polyester (greencap) 4 0 .1µF ceramic or greencap 1 .01 µF ceramic or greencap 1 .0033µF ceramic/greencap 1 330pF ceramic 1 220pF ceramic Resistors (0.25W, 5%) 3 1 OMO 1 4.7k0 1 1 MO 7 1kO 4 1 OOkO 1 1oon 3 47k0 1 470 5 39k0 2 220 1 33k0 1 1 MO miniature trimpot, VR1 Miscellaneous Solder , screws, nuts , lockwashers, double sided copper laminate (see text) hookup wire. the wires are shorted together, the radio should work. Now connect the red (positive) wire to the emitter of the AD162. The black wire then goes to the collector of the AD162. Now, when the AD162 is turned on, it will allow the radio to work. With the circuit powered up, press button S1 and the radio should turn on. If all is OK so far, you are ready to connect the unit to the phone line. You will need a parallel adaptor plug so that the phone and the Music On Hold unit can be connected at the same time. Now apply power and press button S1. LED 1 should light. Now pick up your own phone. You should hear music. Have a friend call you and check that the call can be placed on hold and then reconnected with button S2. The calling party should hear the tuned station from the radio. Adjust the sound level with the radio's volume control and with VRl, if necessary. ~ Problems? ... and you don't have our NEW 1990/91 148 page electronic parts and accessories catalogue ... Its our latest TRADE catalogue for the consumer ARISTA ... Your one-stop problem solver. ... Stylus ... ... Plugs, Jacks and Sockets ... ... Batteries .. . ... Cable .. . ... Tools and Technical Aids ... ... Plug and Power Packs .. . ... Car/Auto Accessories .. . ... Boxed Hi Fi Speakers .. . ... Raw Replacement Speakers ... ... Speaker Accessories ... ... Telephones and Intercom .. . ... Public Address Accessories .. . ... Security and Alarm Accessories ... ... TV/Video/Antenna Accesories ... ... Videocam Accessories ... ... Audio Accessories ... ... Headphones .. . ... Computer Accessories .. . ... Microphone Accessories .. . ...Mixers, Amplifiers, Equalizers ... Just about anything you want. .. Get your catalogue complete wtth "Recommended Retail Prices" free from your local ARISTA dealer or send $2.50 P & H and your return address to: ARIS'I'~ ELECTRONICS PTY LTD PO BOX 191, LIDCOMBE, NSW, 2141 SEPTEMBER1990 45 Deals that will make our Champ 360dpi Hi-Resolution Mouse. More squeak for your dollar! CAT ACCM LIMITED OFFER. If you want a superb quality mouse that is fully Microsoft and Mouse Systems compatible , this is it l The Champ Mouse is a precision pointing device, suitable for all Mouse driven software, including Windows, Word, WordPerfect, Ventura, CAD packages etc The Champ features double the resolution of lesser rodents, with 500mm/sec tracking. Software allovvs software $99 selection of resolution from 60 to 1080 dpi Excellent tactile response and three button design are complemented by the FREE software that provides mouse support for a huge range of non-mouse driven programs. A MOUSE MAT and MOUSE POCKET are also included, but stocks are limited at this price so order early to avoid disappointment I 1. High performance AT/386 Hard Disk/Floppy Disk Controllers Data Switches The Ch eapest XT Turbo Motherboard on the Planet!! • Suits all parallel printers • 2 computers to one printer or one computer to 2 printers • 36 pin centronics connector • Suits aU parallel pnnters • Crossover switch • 36 pin centronics connectors ONLY$39.95 RS-232 Break-Out Box CAT LAAB ONLY$69.95 CAT. MB28612N If you want the performance and flexibility of a 386 machine without the pricetag, you need our new NEAT Chipset motherboard It out-performs 16MHz 386SX systems costing much more yet offers superior flexibility. The board is superbly engineered, with top ·quality surface mount components for the ultimate in reliability Features: • Rechargeable battery backup on the motherboard • Clock speeds of 12 or 16MHz (0 wait state) • Page interleaved memory uses DIL (44256 , 41256, 411000) or SIP memory chips Up to 5MB of mai,1 board memory. Can be config:ired as any combination of DOS, Extended or Expar.ded (EMS) memory. • Shadow RAM function. System ROM and Video BIDS can be mapped to fast RAM for lightning fast response • Expansion sl0ts: 16 bit x 5, 8 bit x 3 • Fast - Land!nark 20 5 (16MHz), 14.8 (12MHz) • Password protection in ROM • Calculator and Timer in ROM • User definable hard disk support. Drives not in the BIDS table can be e ntered by the user and stored in CMOS RAM. 47 disks in ROM plus a user definable place (No 48) CAT MB28612N $499 (12MHz/0WS/0KRAM) Memory Size DRAM 128K Bytes 256K Bytes 384K Bytes 512K Bytes 640K Bytes 424256 X 1 424256 X 2 4242S6 X 3 424256 x 4 or 421000 x 4 424256 x 5 or 421000 x 4 + 424256 X 1 CAT MB28616N $599 (16MHz/0WS/0KRAM) PS/ 2 MicroChannel Memory Card Selling for a limited period at only: $119.00 4 Port Serial Card for UNIX. XENIX etc. CAT.DCAH ONLY $199 SAVE $26 CAT.DCAHF ONLY $225 SAVE $24 CAT 102240 Swts all IBM PC/XT/AT/386 " and IS fully compatible with XENIX, MPM or Multllink Adaptors ONLY $9.75 each ONLY$99 This fantastic little XT motherboard has a full 8 expansion slots and uses just 5 low cost 1MB RAM chips to provide a full640K of memory. The use of advanced ASIC chips means incredible reliability The CPU is a state-of-the -art NEC V20 running at 4.7110MHz (switchable) with zero wait state.s. Size is just 208 x 161mm ONLY$29.95 CAT. LA9M25F 9 pin plug to 25 pm socket CAT. LA9F25M 9 pm socket to 25 pm plug . The appropnate pins connect mtemaUy to allow for ma tchmg of senal equipment using a mixture of 9 pm and 25 pm connectors (eg a 9 pin senal connector on a senal mouse to a 25 pm senal port on a PC) This is Australia's best price on a top quality EGA video card . And you get a FREE printer port (110 selectable) Features include: Full compatibility with XT, AT. 386 Full 256K display memory CAT MBXCI CAT ACDS22 NEAT Chipset PC/AT Motherboards CAT VCEGAC CAT ACDS21 CAT DCAH (HDD) or CAT DCAHF (HDD & FDD) Speed up the disk performance of your AT or 386 machine by a factor of around 21 with these fast caching disk controllers 1:1 sector interleaving , usmg the latest Western Digital 1006 chip set greatly increases performance with most drives . Features: • Capable of addressing hard disks wi th up to 16 heads and 2408 cylinde1s . 1 or 2 drives are supported. • .Will run on a 16MHz BUS on a suitable high speed marnine. delivenng a massive 200% improvement m throughput from this feature alone I • The DCAHF 1s available with a bu!lt-in floppy disk controller. supporting up to 2 drives which may be any mix of 360K or 1.2MB 5 ¼" or 720K or 1 44MB 31/✓. '' dnves Lowest Price EGA card in Australia has FREE printer port! environments. This card provides complete register level com patibility with the IBM Video Graphics Array standard (VGA) . while being backwards compatible with EGA. CGA and Hercules Graphics/MDA monochrome standards . The VC1024 1s fitted with an add1t1onal 256K of d!splay memory for up to 1024 x 768 pixel resolu t10n Normally $349 Only $299, SAVE $50 Two cards ea n be installed in a system and the card 1s AST Four Port/XN hardware and software comoat1ble Corr{es wrth full docwnentat10n . Big saving on current stock only $175 Big savings on these fully IB M Compatible PS/2 memory cards. Provides up to 2MB of memory (OK fitted) on any PS/2 type computer. It uses 1 MB DIP type DRAMs a nd is fully compatible with the IBM PS/2 50/60 Memory expansion option. Normally $299 Save only $249 Phone for details of other M1croChannel products if' our Catalogue . competitors burst into tears!! ........................... I TOP QUALITY ELECTRONIC 1 ■ SOLUTIONS SYSTEMS AT I LOW LOW PRICES. DON'T ■ SEffLE FOR LESS! = I If you want a top quality system at a good price, check these prices. Unlike others , all Electronic Solutions systems use only I top quality components from leading suppliers. Top quality NEC I drives , surface mount technology mother boards, Japanese I keyswitches in the keyboard , etc etc. Don 't settle for less. I 80386SX/20MHz/VGA ■ .20MHZ/386SX system wi\h 16 bit VGA card, I VGA momtor, 1MB RAM; 1.2MB floppy, 40MB NEC hard disk, 2 senal and 2 parallel ports and I genuine Microsoft MS-DOS 4 01. Normally selling I for $3995. Desktop Case standard, Mini Tower I case $75 extra. ■ only$2995 I 80286/12MHz/20MB/EGA I Fast 12MHz zero wait state processor, with quality 20MB drive, 1.2MB floppy, 1MB RAM, 2 I serial and 1 parallel port and genuine MS-DOS 1 4.01. Normally $2395. Desktop Case standard, I Mini Tower case $75 extra. I 1 80286116MHz I As the 80286 system above but with a faster 16MHz CPU. Normally $3495. Mini Tower Case 1I standard. only $2696 I I I I I I I I I I "Professional Look" Vertical ■ Case I ■ I I I I I I I I I I I I I I I Introductory Special only $3795 As the above 80386 system but with 25MHz CPU Normally $5495. Mini Tower Case s tandard. only$3995 Large Tower Case $150 extra with any system! CAT MM1234 Internal or External, includes Software and Cable. 300/300, 1200/1 200 , 1200/75 and 2400/2400 baud only$399 MegaModem 24 CAT MM24 300/300, 1200/1 200, 2400/2400 baud. Inc . cable and Software. only$349 8 9 10 11 MBX C2 IBMXT .JBM PS2 Model 30 DATA COMMUNICATIONS NEW! MegaModem 1234. (OK RAM fitted) ONLY $499 only $199 7 .~~VTEK Deals on Avtek Modems. Sa v e while stocks last! This hig h perlormance PC/AT motherboard has everything I Others charge the same for boards with nothing I I This top 4uality motherboard us es state-of-the-art VLSI technology and surface mount design for best performan ce and reliability. Don 't accept lessi • 12MHz zero wait-state CPU (15 9 MHz Landmark speed rating) • Up to 1MB of RAM on the mothrrboard (OK fitted) Sons or 120nS RAM can be fi tted . • 4 x 16 bit and 4 x 8 bit expansion slots • 2 serial and 1 parallel port buil t in. including cabling • Rechargeable on-board battery backup CATCAESP The case comes complete with cable and specially designed ¼ size card that fits m your PC and will not conflict with your existing hard disk/floppy disk controller. Perteet for fitting 5¼" or 3½" drives or tape backup externally I •••••••••••••••••••••••••• 12MHzPC/AT . ?~ External Drive Case & Controller If you want the fastest XT on planet Earth, this is it Our MBXC2 comes in at a staggering 10.9 on Nortons SI - that 's 31 MHz compared to 4.77MHz on your standard XT The board is fully XT compatible and runs with all standard XT cards. Speed is switchable between standard 4.77MHz and turbo speed. Up to 1MB of RAM can be fitted on-board. For even faster operation, the memory above 640K can be used as "shadow RAM " for speeding up BIOS operations or as a RAM d isk The board provides software selection of wait-state. 80386125MHz cAT Ms2s612v only $249.00( The World's fastest XT Turbo 31MHz XT Motherboard· cAT Msxc2 ONLY $225 80386/20MHz/2MB/VGA Motherboard with the lot!! CATCAESMP This q uality case includes a 5V/1 2V power supply and has standard SCSI connectors and cable. Just fit a SCSI drive and you're in business ONLY $399.00 Fast fully 80386 system with 2MB of RAM, 1.2MB floppy, 40MB NEC hard disk, 16 bit VGA card and Monitor. Professional Style Mini Tower case. Normally $5295. Mini Tower Case standard. I CATCAMTP This brand new Tower case is perfect for any XT AT or 386 machine. Superb styling and heavy d uty construction make this an open and shut ease l A flip down smoked perspex cover protects the drives and power switch from accidental knocks. The power supply is a heavy duty 230W output unit Don't settle for less I Features include: • Drive bays for 3 x 5¼" FDDs or HDDs , two 3½ " FDDs and one 3½" HDD . • 4 LED indicators and Turbo switch • MHz display (2 settings to tie in with "normal" and "turbo" modes) • Heavy 1.44mm steel construction • Dimensions: 7'7/a" x 16" x 15¾" SCSI Drive Cases 10 MHz XT ................................. IBM AT I Electronic Solutions I I Box 426 Glade sville 2111 I Phone (02) 906 6666 I I Fax (02) 906 5222 I We accept: Bankcard, Mastercard & VISA Mail orders our I specialty. Freight on smaller items is now $900 + $2.50 P&P I I • A ll prices include sales tax .,I. • A ll products carry a 14 day money back guarantee (software and hard disks excepted) I I • All Motherboard carry a fu ll 12 month warranty I • A ll products carry a full 3 month warranty I • All cards come with full documen tation • Ring for quantity discounts and tax free prices Owing to technical advances , products we supply may in some cases vary from those pictured. In all cases they a re guaranteed to perform to an equal or higher standard. ................................. Alarm power supply with battery back-up This power supply is designed to go with the Multi-Sector Burglar Alarm described in the June 1990 issue of SILICON CHIP. It's built on a single ·pc board and features a regulated 12V output and battery back-up. By GREG SWAIN Although the burglar alarm described in the June issue of SILICON CHIP can be powered from any regulated 12V supply, an effective alarm system must have battery back-up. Any alarm that can be disabled simply by pulling a fuse at the fusebox is virtually useless. This easy-to-build power supply is the answer to that problem. Nor- mally, it derives power from the mains and delivers a regulated 12V rail to the alarm circuit. However, if the mains supply fails for any reason, it trips a relay and this switches in a back-up battery to power the alarm. Virtually any rechargeable 12V battery can be used to provide this back-up, provided it has sufficient capacity to power the siren if the alarm is tripped. This battery is trickle charged when the mains supply is on to ensure that it is maintained at full capacity. The circuit has also been designed so that the switch-over does not trigger or reset the alarm. This is necessary to avoid false alarms during legitimate power failures and to ensure compliance with noise pollution regulations. Note that although the circuit has been specifically designed for the alarm in the June 1990 issue, it can also be used with most other 12V alarm systems. By combining this power supply with the Multi-Sector Alarm and the Alarm Keypad (SILICON CHIP, July 1990), you can build a fully-featured system for far D7 1N4004 18VAC ►-+--~--..----~--...---t--t-""'11N L~~1o P"ou..,_r___._...,__ _ _ _ _.,__.,.__--41_--, ADJ + 1.Sk 4700 35VW - 4700 _ 3SVW - 10 2SVW I' 10k '\.. 10 2SVW + 4700 - 2SVW 12V TO ALARM CIRCUITRY + 1.Sk _ 0.SW - - - - - - - - - - - - - - - - - -""\ 06 ' 1N4004 B . ,~. ' EOC VIEWED FROM BELOW + 0.1 OUT 12V ALARM POWER SUPPLY Fig.1: 3-terminal regulator IC1 provides a + 12V output to power the alarm, while regulator IC2 provides a + 13.8V output to charge the battery. If the mairis supply fails, Qt & Q2 switch off and the relay contacts close to connect the battery to the alarm circuit. 48 SILICON CHIP 1.Sk o.sw T I 112V 1 BATTERY ...I.. PARTS LIST 1 PC board, code ZA-1454 (copyright Dick Smith Electronics) 3 2-way PC-mounting terminal blocks 1 finned heatsink 3 9mm x 48A bolts 3 48A nuts and washers 1 1 2V miniature SPOT relay (DSE Cat. P-8008) 2 2000 miniature trimpots (horizontal mount) Semiconductors 1 LM350T 3-terminal regulator (IC1) 1 LM31 7 3-terminal regulator (IC2) 1 1 4 4 1 All the parts are mounted on a single PC board, with external connections made via three terminal blocks. Note the heatsinking arrangement used for ICl (LM350). IC2 is bolted directly to the board. less than the cost of equivalent commercial units. Circuit details Ref er now to Fig.1 which shows the circuit schematic. As can be seen, the design is based on two 3-terminal regulators (ICl & ICZ) plus a couple of transistors and a relay. ICl pro~ides the regulated + 1 ZV rail to power the alarm circuit while ICZ functions as the battery charger. The two transistors (Ql & QZ) provide the changeover function when the mains power fails. In greater detail, power for the circuit is derived from a mains transformer with an 18V secondary and this drives bridge rectifier Dl-D4. This circuit, combined with the two 4700µF filter capacitors at its output, gives an unregulated DC rail of about 25V and this is fed to the inputs of the two regulators. We'll briefly explain how these regulators work before going on with the rest of the circuit description. Fig.2 shows an adjustable positive regulator circuit based on the LM350. Capacitor Cl filters the DC input to the regulator while VRl, Rl and RZ set the output voltage. In operation, the regulator produces a fixed 1.25V between its output (OUT) and adjust (ADJ) terminals. This means that VRl sets the current through Rl and RZ and this in turn sets the voltage on the ADJ terminal. By suitably adjusting VRl, we can thus set the output voltage to the required value (it will always be 1.25V higher than the voltage on the ADJ terminal). Since the current flowing from the ADJ terminal is negligible, we can derive a simple formula for the output voltage as follows: VouT = 1.25 (1 + RZ/(VRl + Rl)) In Fig.1, Rl is 4700, RZ is 4.7k0 and VRi' is a 2000 trimpot. Thus, Fig.2: basic scheme for an adjustable 3-terminal regulator circuit. The regulator maintains a constant 1.25V between its OUT and ADJ terminals. BC548 NPN transistor (01) BC558 PNP transistor (02) 1 N5404 3A diodes (D1 -D4) 1 N4004 diodes (D5-D8) 1 2V 400mW zener diode (ZD1) Capacitors 3 4700µF 35VW axial electrolytic 2 1 OµF 25VW tantalum 1 0. 1µF ceramic Resistors (0.25W, 5%) 1 2 1 2 1 OkO 4.7k0 1.5k0 1.5k0, 0.5W 2 1 kO 1 4700 2 3900 VRl can be varied to give a theoretical output voltage range of 10.0ZV to 13.75V. In practice, VRl is adjusted to give an output voltage of exactly 12V. This output voltage is filtered by a 4700µF capacitor and then fed to the output terminals. The parallel lOµF capacitor is included to protect ICl against high frequency oscillation while the lOµF capacitor at its ADJ terminal greatly improves the ripple rejection. The 1.5k0 resistor across the output terminals sets the minimum load current to ensure correct operation of the regulator. ICZ (LM317) works in exactly the same way as ICl but has a lower current rating (1.5A vs. 3A). Its output is set to 13.8V by VRZ and this is used to trickle charge the 1 ZV backup battery. As before, a 1.5k0 resistor is used to set the minimum SEPTEMBER 1990 49 capacitor at the output of IC1 prevents glitches on the supply output during changeover, to prevent false triggering. Construction Fig.3: here's how to install the parts on the PC board. Take care with component orientation and be sure to use the correct transistor types for Qt & Q2. The two 1.5k!l resistors near the relay must be rated at 0.5W. load current while the · 0.1µ,F capacitor ensures regulator stability. Note that no bypass capacitor has been used on the ADJ terminal here since output ripple from this regulator is not an important consideration. Diodes D6, D7 and DB protect the regulators against discharge currents from the external electrolytic . capacitors and the battery if the mains power fails. In addition, the regulators also include built-in short circuit and thermal overload protection. If their ratings are exceeded, the devices shut themselves down by current limiting. Changeover circuit Now take a look at transistors Ql and QZ. As mentioned previously, these control the changeover function. Basically, Ql functions as a simple comparator. It compares the voltage at the output of the bridge rectifier with a reference voltage on its emitter as set by zener diode ZD1 (12V 400mW). Normally, when mains power is present, Ql is turned on and so Q2 and the relay are also on. The relay contacts are therefore held open and the battery is disconnected from the output. However, if the input to the regulators falls below about 15V due to mains failure, Ql, Q2 and RLY1 all switch off and the relay contacts close. This connects the battery to the output and so it now supplies power to the alarm circuit. The two 4700µ,F filter capacitors at the output of the bridge rectifier ensure that the regulators remain in regulation during the changeover time. In addition, the 4700µ,F All the parts (except the power transformer) are mounted on a PC board coded ZA-1454. Fig.3 shows the assembly details. Before installing any parts, check the copper pattern of the board for possible defects. In particular, check for open circuit tracks and shorts between tracks due to incorrect etching. Once this has been done, install the two wire links and all the resistors. Refer to Table 1 for the resistor colour codes when you are installing the resistors. Alternatively, you can use your digital multimeter to check the resistor values. The diodes, trimpots, transistors and the smaller capacitors can now be installed on the board. Before soldering their leads, check that all polarised components (diodes, transistors and tantalum capacitors) are correctly oriented. Also, be sure to use the correct transistor type at each location and note that diodes D1-D4 must be 1N5404 types which are rated at 3 amps. External connections to the board are made via three 2-way PCmounting blocks and these can be installed at this stage. You can also now install the relay but leave the big 4700µ,F filter capacitors off the board for the time being. The next step is to mount the heatsink. This is supplied predrilled with the kit (see panel) and is secured to the board using two 3mm bolts and nuts, one of which also secures the LM350T regulator (IC1). Bend the regulator's leads at right angles and smear its metal tab with heatsink compound before TABLE 1: RESISTOR COLOUR CODES □ □ □ □ □ □ □ 50 No. 1 2 3 2 1 2 SILICON CHIP Value 10k0 4 .7k0 1.5k0 1k0 4700 3900 4-Band Code (5%) brown black orange gold yellow violet red gold brown green red gold brown black red gold yellow violet brown gold orange white brown gold 5-Band Code (1%) brown black black red brown yellow violet black brown brown brown green black brown gold brown black black brown brown yellow violet black black brown orange white black black brown Smear heatsink compound on the metal tab of the LM350T regulator before bolting it directly to the heatsink. Check that the edge of the heatsink doesn't short against any nearby component leads. bolting it down. Don't forget to solder the regulator 's leads on the copper side of the PCB. The leads of the LM317 regulator must also be bent at right angles. No heatsinking is required for this device - it is mounted directly on the PCB (metal tab down) and secured with a 3mm bolt and nut. Assembly of the PCB can now be completed by installing the three 4700µF capacitors and the relay. Watch the polarity of the capacitors - you'll strike problems if you install them the wrong way around. Testing & adjustment To test the unit, you will need a mains transformer with an 18V AC secondary. The recommended transformer is the type M-1990 which is rated at 2.2A and is available from Dick Smith Electronics. Alternatively, you can use a DC supply capable of putting out about 20V DC (anything from 18-25V will be OK). If you are using a DC supply to test the unit, it should be connected to the inputs of the bridge rectifier (ie, directly to the terminal block on the PCB). You don't have to worry about the polarity of the DC supply - the bridge rectifier will take care of that. Don't connect the alarm circuit or the back-up battery at this stage. Now apply power and check that the relay operates. If it does, use your multimeter to check the voltage at the 12V OUT terminals. Adjust trimpot VRl for a reading of exactly 12V. Similarly, check the voltage at the BATTERY terminals and adjust VR2 for a reading of 13.BV. Once the outputs have been adjusted, switch off the power and check that the relay contacts close. If the relay fails to operate when power is applied, check Ql, Q2 , ZD1 and their associated resistors. Check also that D5 is correctly oriented. If you are unable to adjust either output to the correct value, check the resistor values and diodes around the relevant regulator. The completed project can be installed in a lockable steel case, along with the alarm PC board, the power transformer and (if it fits) the back-up battery. Make sure that you install the power transformer and its associated mains wiring in a professional manner. The 12V back-up battery should have a minimum rating of 1.2AH. 1§;1 Where to buy the kit This project was developed by Dick Smith Electronics and is available from all DSE stores or by mail order from PO Box 321, North Ryde, NSW 2113. You can also order by phone on (02) 888 2105 or, from outside the Sydney area, on (008) 22 6610 . The kit consists of a PC board plus all the on-board components (including the heatsink) but does not include the transformer or a backup battery . The price is as follows: The power supply is ideal for use with the Multi-Sector Burglar Alarm described in June 1990 SILICON CHIP. This unit features variable exit & entry delays, timed & latched outputs, and two separate sector inputs. The number of sector inputs can be easily increased by means of an add-on board. 12V Alarm Power Supply (Cat. K-8402) .............. .. ..... .... .. ... $39.95 Power Transformer (Cat. M-1 990) .. ................... .... .. .. .... .. ... $22. 95 Postal orders should include another $4 .50 for postage or $6 .50 if the power transformer is included in the order. Please quote the catalog numbers when ordering . Note: copyright of the PCB artwork associated with this project is retained by Dick Smith Electronics. SEPTEMBER 1990 51 HS-3000 Plus HANDY SCANNER "THE TOTAL SCANNER SOLUTION" For uses with: DESKTOP PUBLISHING WORD PROCESSING CAD APPLICATIONS DATA BASE WIDE 4 .13" (105mm) SCAN WIDTH 100/200/300/400 SWITCHABLE DPI RESOLUTION WAS $499.00 NOW ONLY GOODWILL GOS-622 20MHz 2CH. OSCILLOSCOPE * Display: CH1, CH2, DUAL, CH1, CH2, X-Y. * Sweep Modes: Auto, Normal, Single Shot. * Auto Trigger Level Lock, Variable Hold-Off. * Sensitivity: 5m\//DIV to 5V/DIV to 20MHz. * INCLUDES 2 x 1:1 10:1 PROBES * ONLY $38 PORTASOL "PRO" GAS SOLDERING IRON KIT Designed for the craftsman, technician, or professionals requiring micro-precision soldering with adjust?ble power equivalent to 60 watts. Complete kit includes Portasol tool, 4 tips (Soldering iron, Blow Torch, Hot Blower, Hot Knife), safety stand, cleaning sponge and handy storage case. ii;;;;;;;;;;;;;;;;;;;;~~r~~ sii~o * 1600 WATT HEATGUN Two heat settings: 400°C/600°C. Great for heatshrink tubing, paint stripping, or bending PVC pipes. AALEC l:;JUAL ■TY watch with every purchase 2 way $39.00 3 way $49.00 4 way $69.00 "DRILL 'N' DRIVE" NOW Two speed cordless Drill and Screwdriver. $59.95 * Auto and manual range operation. * AC/DC ampere measurement. * Logic test function (CMOS/TTL). * Data hold and diode test functions. * Fast response continuity buzzer. CROSS-OVER 2 WAY SWITCH BOX , $55.oo HDS-90L PROBE TYPE DIGITAL MULTIMETER * DB-25 TYPE * CENTRONIC 36 PIN TYPE Control two computers and two printers. • ONLY PADDUC:TS . - . , , RECHARGEABLE COMPUTER DATA SWITCH-BOXES . . . •h * $799.oo 12 MONTHS WARRANTY D8·25 type $59.95 NOW ONL y . . . : ::Ce : n:tr:o:ni:c:3:6:p:in:t:yp:e:$:5:9:.9:5::::::::~==*::L:~:ge:3:.5::dig:it:L:C:D:d:isp:la:y·::*:1:2:m:o:nt:hs:w:a:rr:an:ty:.:::$:5:5::·0:0::::: I 11111 D All EMTEK UPS-501 UNINTERRUPTIBLE POWER SUPPLY 500 WATT Ni-Cad BATTERY PACKS -a Iii For most cordless phones and computer battery back-ups The UPS provides instant emergency inverter power in the case ot mains distubances or failure. * ••• if%)h ~ ~I ~ a ~ ================:::=========== Qlli * 500 watt Back-up time: 7 min. full load. ~ " =· To suit most cordless phones. To suit most.co~puters for battery back-ups. 9.6 volt $24.95 3.6 volt $13.95 We've seen comparable units sell for well over $1,700.00 PLA YMASTER "PRO SERIES ONE" HIGH POWER AMPLIFIER KIT NORMALLY $599.00 NOW * $549.oo Output power: 140W RMS into Bohm. 200W RMS into 4 ohm. Distortion: 0.005% at 1DOW into 8 ohm. Frequency response: 1DKl to 1OOkHz. VIDEO . TRANSMITTER Ideal for watching a video in the bedroom, kitchen etc. without having to move your complete VCR system or having long extension cables running from one end of the house to the other. * Output channel: UHF 30 * Transmitting distance: 1Omtr. * Complete with power supply and connecting cables. ONLY * $89.95 127 YORK STREET SYDNEY 2000 PH: (02) 267 1385 BUSINESS HOURS: Mon-Fri 8:30 to 5:30, Thurs 8:30 to 7:00, Sat 9:00 to 1 :00 * CASSETTE TAPE ERASER MULTI-LINGUAL POCKET TRANSLATOR Simply pass the cassette through the eraser several times. • No batteries or liquids required . 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Res. 80Hz to 20KHz . . .• Size 180x107 x131m* . ; NOW ONLY · $49.95/PR • Surge Capacity: to 4500 Amps. • Maximum continual voltage: 27.5 volts. • Reaction time: less than 25 nanoseconds • Clamping voltage : 71 O volt, 50 amps. • Energy absorption factor: 75 joules . NOW ONLY $21.95 PRO-SERIES CD101 0A 5.25" DUAL CONE CAR SPEAKER • SPL. 94dB • Complete with grilles. MAIL ORDERS: P.O. BOX 0103 SYDNEY 2000 PHONE ORDERS: (02) 267 1385 FAX: (02) 261 8905 ' ~- NOW ONLY PRO-SERIES 3 WAY CAR SPEAKER SYSTEM • 45 watts. • 4 ohms • Fre . 90 to 19KHz. ~ -l • Sine and Square wave output. • Freq . range: x 1 range 20Hz to 1.5KHz x 100 range 2KHz to 150KHz • Output control: OdB, -20dB plus fine adjuster ; ~ · • Output impedance: 600 ohm +/- 10% • Operates on a sinqle 9 volt battery LIGHT WEIGHT STEREO HEADPHONES I -~-.F- ''] . . ; na~. ~ 1:~!k-•___- ·_·-.,~ ~~...-=. ==~ . ·..·. .~f~;;·y. ,, •..,,l= .• i__e;: c.,,,._ . STEREO 6.5mm PLUG to 2 x 6:5mm STEREO SOCKETS on individual 8 metre cords. only $6.95 ea. Freq . Res. 20Hz to 20KHz Impedance 32 ohm 4 ft. lead with stereo 3.5mm plug 3.5mm ST. skt. to 6.5mm ST. plug adaptor included ~ liiiiiiia ..;~. MULTIFUNCTION CAR ALARM with WIRELESS REMOTE DUAL HEADPHONE EXTENSION LEAD • • • • ONLY $7 .95 CASSETTE SALVAGE and REPAIR KIT NOW ONLY $59.95/PR POST & PACKING $5-$25 $26-$50 , \ . l / Ideal for computers, tv and videos , etc. MORE SPECIALS IN THE FRONT OF THIS MAGAZINE ... $3.oo ..... $5 .00 $51 -$1 oil . $101 -$499 . ... . .. . . I $500+ FREE EE Build this low-cost 3-digit counter module Looking for a cheap module for event counting or to be used as part of a larger project? If so, consider this 3-digit counter module. It uses only two low-cost CMOS ICs and can be put together ..in a couple of hours. By DARREN YA TES Over the past few years, there have been quite a few designs for 3 or 4-digit counters which have either used the 74C92X-series 4-digit counters or a string of 4029 CMOS single digit counters. The basic problem with these, designs is that they are too expensive or physically too big. The 74C92X-series counters are a good example of the former. While they are very compact 54 SILICON CHIP devices and require very little PCB space, at up to $17 each, they are too pricey for the average experimenter. On the other hand, a counter based on a string of 4029 single digit counters has the problem of going the other way. While 4029s are quite cheap, they require a dedicated 7-segment display driver for each digit. For a 3 or 4-digit counter, this ends up being 6-8 ICs and uses up board space like it was going out of fashion! The circuit described here strikes a balance between these two problems. It uses the sometimes forgotten 14553 CMOS 3-digit counter IC from Motorola (also available as the GD4553 from Goldstar and sold by Novocastrian Electronic Supplies, PO Box 8 7, Broadmeadow, 2292). This device is quite cheap at about $4 and requires only a single 4511 7-segment display driver plus 3 transistors to produce a 3-digit event counter. 4553 functions To understand this IC, you'll need to read the text and follow the block diagram in Fig.1. Looking at the diagram, the IC contains three BCD counters whose 4-bit outputs are each passed through a four-bit register or quad latch. These allow us to store a certain count and have it displayed at the output, while the counters themselves are still counting. We'll talk about some practical uses of this feature a little later. The way in which the digits are displayed is achieved by using a technique known as multiplexing. The outputs from the three quad latches are fed into a quad 3-input mulitplexer. A multiplexer is just like the input selector switch on your stereo amplifier except that instead of you rotating the switch between the different input sources, it is done automatically and continuously, so that each of the sound inputs is heard for a short time at the loudspeakers several times a second. This is basically what the counter IC is doing with each of the digits. The scan oscillator drives a scan counter whose outputs, Q0 to Q2, continually select each digit in sequence at a reasonably fast rate. The 4 bits of that digit then appear c,.b .---- - ® r-----, '© --i_ ®- ~ T r.: •ULSE GENERATOR LSD ® Bio <at> CP 1 >-of><>-1,-.of COUNTER 0 CP "o 1--- -+-i 01 D1 QUAD 01 LATCH 02 a 2 02 03 D3 03 QUAD 3-I NPUT MULTIPLEXER If CP1 is kept low and the clock signal is fed into CP0, then the counter increments on the negative or "falling" edge of the clock signal. If, however, CP0 is held high and the clock signal is fed into CP1, then the counter is triggered by the positive or "rising" edge of the clock signal. OK. That's how the 4553 IC works. Now let's take a look at the circuit diagram in Fig.2. The circuit As you can see from the circuit diagram of Fig.2, the module uses two ICs, a handful of resistors, a couple of 7-segment displays and Oo a, oo, l~UT~~ a, a 2 t--1---+-i , a, 03 03 D3 PARTS LIST "o MR a, 1--1-----1 Dt QUAD 0t a,1--1-----1 02 LATCH 02 03 03 l--i.----1 a, z, }, a, a. a,® o, MSO Voo = Pin 16 V55 • Pin 8 0 = Pin Number TC MR <at> ® Fig.1: inside the 4533 3-digit counter. It contains three BCD counters, with each counter driving a 4-bit latch. The latch contents in turn drive a quad 3-input multiplexer. at the output pins, Q0 to Q3. The end result is that the 4 bits of each digit appear at the output pins at small discrete time intervals. In order to recreate the three digit number, the outputs of the scan counter are provided at pins 2, 1 and 15 respectively. These outputs, marked "DSO0" to "DSOZ", are used to drive each of the 7-segment displays in turn via a switching transistor at the correct time interval. Even though each 7-segment display is only switched on for a third of the time, our eyes cannot detect this fact. This is because the speed at which they are switched is faster than the eye can respond. As a result, the display appears to have a constant brightness and does not flicker. The speed of the switching is set by the external capacitor fitted to the scan oscillator at pins 3 and 4. The larger its value, the slower the output cycles between digits. The IC also has several usercontrolled inputs which make this counter a very versatile unit. The MEMORY RESET input (pin 13), when taken high, resets each of the three counters back to zero. The LATCH ENABLE input at pin 10, when taken high, stores the current value of each of the three counters in the corresponding latch and continues to send this count to the output and the displays. The TERMINAL COUNT output at pin 14 is an overflow output which goes high for one clock cycle when a count of "999" is reached. The counter then resets back to "000". There are also two input clock pins, labelled CP0 and CP1. By correct selection of these, it is possible to make the IC increment on either the positive or negative edge of the clock signal. PC board, code SC04309901 , 11 8 x 80mm 7 PC pins Semiconductors 1 4553 CMOS 3-digit BCD counter (IC1) 1 4511 CMOS 7 -segment decoder driver (IC2) 1 7805 5V regulator 3 BC328 PNP transistors (01 ,02 ,03) 3 FN_D500 or equivalent common-cathode 7 -segment displays Capacitors 1 1 OOµF 16VW electrolytic 1 .001 µF metallised polyester (greencap) Resistors (0.25W, 5%) 3 1 OkO 5% 1 220fl 1 % 7 6800 5% 1 1500 1 % Miscellaneous Hook-up wire, solder. little else. It is basically a "barebones" job in that the board itself contains only the basic parts necessary for it to operate. This allows the builder to add on other "extras" as they are needed rather than pay for something they may not use. To make external connections easier, the controlling inputs are brought to the bottom of the board for easy access. IC1 is the 4553 3-digit counter IC. The .001µF capacitor on pins 3 and 4 sets the multiplex scanning rate SEPTEMBER 1990 55 ponents on the board. Follow the wiring diagram of Fig.3 when assembling the components onto the board. Next, solder in all the wire links. Once you've done that, wire in all the resistors. This should be an easy job but be careful about solder splashes shorting out nearby tracks; don't use excessive amounts of solder. The electrolytic capacitor goes in next. Make sure you get its polarity right - the positive pin goes to the outside of the board. The .001µ.F capacitor associated with ICl can also be soldered in at this stage. Next, do the three PNP transistors, making sure that they are all oriented correctly - see the photo to double check this point. Finally, solder in the two ICs and the three LED displays. Check the orientation of the two ICs carefully +9V 3 4 16 BL 5 3xFND500 7x68Dn , 13 b 12 LE C11 IC2 4511 .,. 4 d 10 1 e9 a ,,-g-,b ·I /c f 15 d g 14 10 A B C 0 7 1 2 6 7 6 5 01 02 03 15 OS3 TERM COUNT 1 14 TC LATCH ENABLE 2 10 LE 11 CP1 3 12 CPD 4 02 BC558 IC1 4553 CP1 DS2 1 .,. CPD 13 MR MASTER RESET 5 01 BC558 DS1 03 BC558 2 C1A 3 GND6~ ,. .001 i,aD;:;.:UT-------+gv 100 + B EOc 16VWJ VIEWED FROM BELOW GNO .,. LOW-COST 3-DIGIT COUNTER Fig.2: ICl is the 4553 counter IC and this drives 7-segment decoder IC2 and the digit driver transistors (Ql-Q3). IC2 in turn drives the display segments while Ql-Q3 switch the displays. to about lkHz, depending on the exact value of the supply voltage. The 4-bit outputs (Q0 to Q3) are fed into a 4511 CMOS 7-segment decoder/ driver (IC2). The outputs of this driver are connected to the three 7-segment displays which have their corresponding pins connected together. Each display is switched on at the correct time via the display control outputs at pins 2, 1 and 15 (DS1, DS2 & DS3). These are activelow outputs; ie, for a particular digit to light, its displ1;1y control out- put must go low rather than high. These outputs each drive a BC328 PNP transistor (Q1-Q3) via a 10k0 resistor and the transistors in turn switch the common cathodes of the display digits. Building the module The board itself should take no more than a couple of hours to put together. When you etch or buy the printed circuit board, make sure that there are no shorts or breaks in the tracks. If you do find any, fix them before you mount any corn- Fig.3: the unit is easy to wire up but be sure to orient the three displays correctly. The decimal point of each display goes to bottom right. RESISTORS □ □ □ □ □ 56 No 3 7 1 1 SILICON CHIP Value 10k0 6800 2200 1500 4-Band Code (5%) brown black orange gold blue grey brown gold red red brown gold brown green brown gold 5-Band Code brown black black red brown blue grey black black brown red red black black brown brown green black black brown I ■ HUGESCOOPPURCHASEfamous brand FACIT 4510 80 column 9 pin dot matrix at a never-to-be-repeated bargain price! Equipped with both parallel AND serial interfaces as standard! Includes emulation for both Epson AND Facit Handles cut forms and standard stationery by friction feed and fan-fold paper by traction feed, all standard . ~ .":-:-. • • 3 carriage speeds ~ - - allowing variation in length of each character 128 character constant pitch alphanumeric --W:l~ fonts which gives eight 96 character national character sets Comprehensive range of user commands for remotely controlling printer operation Optimised bidirectional printing, line oriented Operator's control panel for effective local control of printer operation YES! INCLUDES OUR FAMOUS 14 DAY MONEY-BACK SATISFACTION GUARANTE ELSEWHERE YOU'D EXPECT TO PAY UP TO· BOARD SOLUTIONS PRICE- ONLY s3gg s249 . 2K Word input buffer PHONE, FAX OR MAIL ENQUIRIES WELCOME p~s~:i. BOARD SOLUTIONS Ply Ltd PO BOX 1120, LANE COVE NSW 2066 TEL (02) 906 5696 FAX (02) 906 4592 and note that the decimal point of each display goes towards bottom right. Testing Once you're sure that all of the components have been correctly positioned and soldered onto the board, you can test it using the following method: First, if you look closely at the board, you'll see that the output pin of the 7805 regulator [the pin closest to the ICs) has two tracks running from it. One goes to a 2200 resistor and the other goes to a wire link. This wire link will be used as the positive supply line. Now, either use a clip lead or solder in a piece of wire from this link to the CP0 input at pin 4 on the user port. Use two more clip leads to tie pins 2 and 5 to the ground pin [pin 6). Now feed a low-frequency (say about lOHz) clock signal of no more than 9V peak to the clock input at pin 3 of the port. You should now see the counter start counting. If this is the case then all is well. Using the module As mentioned before, the module is designed to work with other devices. Fig.3 shows how the user port at the bottom of the board is arranged from the component side. Pin 1 is the overflow output. If you wish to combine a number of these counters to produce a 6 or . maybe even a 9-digit counter, link this pin to the clock pin [CP0 or CPl) of the next counter module. Pin 2 is the LATCH ENABLE input. This pin is normally held low while 0 ===.ri=::. . --.. SU SC04309901 ~ 00 0 Fig.4: here is a full-size reproduction of the PC artwork. the clock is counting and taken high to store a particular count without having to stop the counting process. This can be used, along with the master reset pin, to turn the counter into a low-cost frequency meter. Pins 3 and 4 are the clock inputs. Note that no buffering or amplification has been given to these inputs. The signal is just fed straight into the IC from the user port pins. Again, the idea of this board was to produce a versatile design. If you intend to use this board with a CMOS project, and provided the supply voltages are the same, you most probably won't need to buffer the signal. If, however, you are using small signal equipment, you'll need to add these on via an external board. The SOUND AUSTRALIA SOUND AUSTRALIA SOUND AUSTRALIA SOUND AUSTRALIA can offer you everything from electronic components to professional public address systems Amplifiers - 100 Watts to 1800 Watts/mixers, speakers, microphones supersoft high quality coloured microphone cable + many more electronic accessories BRING ALONG OR POST THIS AD TO RECEIVE A $5 GIFT VOUCHER Ph (03) 791 1622. 28 Walker St, Dandenong 3175 58 SILICON CHIP choice is left up to you. So too is the choice of either rising-edge or falling-edge triggering by the clock signal. Pin 5 is the MASTER RESET pin. In normal operation, this pin is held low, and taken high to reset the counter at any time. Pin 6 is the ground rail, while pin 7 is the positive supply line. An important point to remember is that the voltage on any of the user port pins should not exceed the regulator output voltage. So, if you're using the 7805 regulator to provide a 9V supply, don't allow any of the input pins to go higher than 9V to prevent damage to ICl. If you want to power this project with from existing CMOS circuitry power supply, you can remove the 7805 regulator and the 2200 and 1500 resistors and just put in a wire link between the two outside holes of the 7805's position on the board. If you do this, make sure that the supply voltage doesn't exceed + 15V. To have a regulated 5V supply, leave the 7805 in place, remove the 2200 resistor and replace the 1500 resistor with a wire link. If you change the supply voltage, you'll need to check that the seven display resistors are not too small or too large in value. A good rule of thumb is that the resistors should be about 3300 for a 5V supply, about 6800 for a 10V supply, and about lkO for a 15V supply. ~ Dick Smith Electronics say . .. Look to the Future Board Solutions say ... Look to the Future, to the Features AND to the Price! HERE ARE 4 BETTER REASONS WHY YOU WON'T BUY YOUR NEW 386SX COMPUTER FROM DICK SMITH ELECTRONICS: YOU'LL BUY IT FROM BOARD SOLUTIONS! 1 • • • • • • • • THE COMPUTER • Famous brand Ultima 386SX • Truly super fast 20MHz 80386SX (not the slower 16MHz version they sell) • 12120MHz speed keyboard or software switchable 1MB RAM on board, expandable to a massive 10MB (theirs expands to only 5MB) 42MB 28ms voice coil hard disk drive 1.2MB 5-1 /4in disk drive Western Digital hard/floppy disk controller card 16Bit 256K VGA Card 2 serial , 1 parallel ports built in 14in VGA Colour Monitor (not a "monochrome VGA" ours is true VGA colour included in price!) Mini tower case with LED display 2 THE QUALITY Ultima offers outstanding reliability and cost effectiveness. Crafted using the latest surface mount technology, all systems are fully QC'd during assembly in the factory, and then undergo complete quality control again at Board Solutions before being despatched to you. All Ultima computers from Board Solutions carry a full 12 month "back to base" warranty. We're so confident we offer all purchasers our 14 day money-back satisfaction guarantee. 3 THE SUPPORT If for some reason you need to return your 20MHz 386SX Ultima Computer, we will guarantee to have it repaired and ready to despatch within 48 hours (normal turnaround is less than 24 hours) . Why wait up to six weeks with some other companies? THE PR ICE 4 Remember, this is a 20MHz 386SX, not 16MHz. Remember, this includes a colour VGA monitor, not a $500 "option"! OUR PRICE : Only s2995 Retail Customers Only including VGA COLOUR Monitor you don't have to add a thing! PHONE, FAX OR MAIL ENQUIRIES WELCOME f l ~ S ~ 4- BOARD SOLUTIONS Pty Ltd PO BOX 1120, LANE COVE NSW 2066 TEL (02) 906 5696 FAX (02) 906 4592 Kenwood CS-6020 1501\1Hz oscilloscope with CRT readout Kenwood's new CS-6020 150MHz oscilloscope represents a big step forward in user facilities for a given price. It features CRT readout to display channel settings and it can display up to 8 traces simultaneously. panel. This helps make the controls less cluttered and easier to use. Even so, all the major operating functions of the instrument are indicated on the front panel by rectangular LEDs. Specifications Below: voltage, time and frequency measurements can be made quickly and accurately by aligning two cursors on the waveform. The reading is displayed in the top right hand corner of the screen. voltage fields which sweep it across the tube face to produce a visual analog of the waveform being measured. When it is producing alphanumeric information on the screen, it does so by the same raster sweep process that is used for TV screens and computer monitors. The numbers and letters are produced in a dot matrix, which can be clearly seen if you look at the numbers through a magnifying glass. Just how the instrument's electronics manage to produce both a vector scan for the traces and a raster scan for the alphanumeric display is beyond the scope of this article but it is a complex task handled by a microprocessor. Where this Kenwood instrument differs from most earlier CROs with CRT readout is that since the CRT shows most of the settings on the screen, a lot of the labelling has been eliminated from the control Essentially, the Kenwood CS6020 can be regarded as a 2-plus2 trace oscilloscope. Channels 1 and 2 have full input attenuators while channels 3 and 4 are auxiliaries with only two input sensitivies available. Channels 1 and 2 have a sensitivity of 5mV to 5V/division selected via a rotary attenuator switch with a 1-2-5 sequence. The upper - 3dB frequency response on these ranges is 150MHz. For the same channels, a sensitivity of lmV/division is available but with the - 3dB response reduced to 20MHz. Either channel may be AC or DC coupled. Channels 3 and 4 have a sensitivity of 0.1 V or 0.5V/division (selected via pushbutton switches) and a frequency response to 150MHz ( - 3dB). Both of these channels are DC coupled only. The horizontal axis input is via channel 2 and this has the same Voltage measurement Time measurement Frequency measurement Oscilloscopes with CRT readout (ie, channel settings displayed on the screen) have been around for quite a few years but this feature is now becoming available on much cheaper instruments. Briefly, the oscilloscope beam is made to do double duty; it not only displays the various traces that are required (which can be up to 8 on this model), but also displays the various input settings for the four channels, the timebase settings and other data such as the time and date. Normally, oscilloscope traces are produced by the vector scan method; the electron beam is subjected to vertical and horizontal 60 SILICON CHIP Despite its impressive range of features, the CS-6020 is easy to use. Most of the control settings are displayed on the CRT, thus eliminating a lot of labelling from the front panel. The unit can display up to 8 traces simultaneously and either horizontal or vertical cursors. sensitivity as when used in the vertical mode but the frequency response is reduced to 2MHz. The vertical mode to be displayed is selected by the following pushbutton switches: CHl, GHZ, CH3, CH4, ADD, CHOP/ALT, GHZ INV and 20MHz BWL (bandwidth limited). Two timebases There are two horizontal timebases: main (A) and delay (B). They may be selected as A only, A INT B (B displayed as an intensified portion of the A sweep), ALT (A sweep intensified for duration of B sweep, alternating with delayed B sweep), B sweep only and X-Y when CHl, CH3, CH4 may be used for the vertical inputs and CH2 for the horizontal input. Sweep speeds are selected via a rota·ry switch and range from 20ns to 0.5s/division. Trigger delay of the delayed sweep (B) is from 0.2 to 10 times the A sweep time setting. A x 10 magnification function is also available via a pushbutton switch, giving a maximum sweep speed of .02ns/division. Triggering of the timebase can be from any of the four vertical inputs and line (ie, 50Hz mains supply). Trigger coupling may be AC, DC, Noise or HF rejected, TV Frame or TV Line. Triggering Trigger mode may be Auto/Normal, Single Shot and Fix. This last mode is interesting in that it overrides the Trigger level control and triggers the timebase close to the zero crossing of the input waveform. This greatly simplifies stable triggering of difficult signals and makes the CRO that much easier to drive. The B sweep has a further mode: TRIGGER COUNT. When the CRO is used for observing TV signals the TRIGGER COUNT · switch is pushed and the required trigger count number (n) can be set using the LiREF/DELA Y POSITION control. The B sweep then triggers on the nth count of all the TV synchronising pulses (equalising, vertical and horizontal). In this mode the complete TV frame signal is displayed by the A sweep and the required line signal is displayed by the B sweep. CRT readout Two lines of alphanumeric data are displayed on the screen. At switch-on, the line at the top of the screen indicates the month, date, year and time. The main functions displayed on the line at the bottom of the screen include the vertical sensitivity of the selected channel or channels, and the selected sweep speed for the main and delayed timebases. When either the vertical input or timebase VARIABLE controls are used, the relevant readout is preceded by a ) symbol. Two horizontal cursors can be placed on the screen to measure voltages on different parts of waveforms. Similarly, two vertical cursors can be placed on the screen for the measurement of time delay, frequency , phase or ratio. When the cursors are in use, the top line of the display shows (in addition to the time and date) the voltage difference between the cursors for either channels 1 or 2 when the input attenuator is in the calibrated position. Alternatively, it displays the voltage ratio between SEPTEMBER1990 61 Kenwood CS-6020 1~0 MHz Oscil,oscope Voltage ratio measurement Time ratio measurement Phase measurement Rise time measurement Delay measurement Trigger counter These photos show some of the other measurements that can be made using the cursors. The trigger count function is shown at bottom right. The top trace shows a composite video signal at a sweep speed of 5ms/div, while the bottom trace shows line 312 at O.lms/div. the cursors as a percentage (with five vertical divisions representing 100%) when the input attenuator is uncalibrated ie, when the VARIABLE control of the attenuator is adjusted away from the CAL position. Similarly, if the vertical cursors are in use, the top text line shows the time difference or 1/time (frequency) between the cursors. Other information displayed can be the phase difference between the cursors (with five horizontal divisions representing 360°) when the timebase variable control is used, or the delay time when sweep B is active. Use of the cursor controls is uncomplicated and simply requires selection of the wanted function (~Vl, ~T. etc) by the relevant pushbutton switch. The ~REF/DELAY POSITION control is then used to position the first cursor to the part 62 SILICON CHIP of the waveform from which the start of measurement is to be made. The ~ control is then adjusted to place the second cursor at the end of the measurement and the readout displays the value in the top right-hand corner of the screen. In this way measurements can be made of waveform amplitude or period in whole or in part. Measurement accuracy for voltage or time is ± 3 % but as making a measurement depends on careful positioning of the cursors by the user, this also becomes a factor in the final accuracy. Because of the measurement method, even if there is no signal input, a reading will be indicated, dependent only on the positions of the two cursors on the screen. Probe switching Two divide by 10, 150MHz probes are supplied with the CS-6020. Plugging these probes in means that the vertical input sensitivity is automatically reduced by 10, for example from 5V/div to 50V/div. This could cause confusion when taking measurements off screen but Kenwood gets around it by using special probes which have a pin at their connector end. When plugged into the CHl or CH2 inputs, they change the readout accordingly. We 11l have one Despite the number of functions the CS-6020 provides, we found it a very easy and pleasant instrument to use. This is in contrast to many CROs which can require a lot of time just to get a trace on the screen, let alone make measurements. Price of the Kenwood CS-6020 oscilloscope is $3980 plus tax, where applicable. This includes the two special probes. 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Unbeatable performance and value ■ Three year warranty ■ 3½-digit, 3200-count display ■ 31-segment analog bar graph ■ Single rotary dial to select all fu nctions ■ Autoranging and automatic polarity selection ■ Batterysaving "Sleep Mode" powers-down display if you foqiet ■ Tough, textured case resists drops and rough handling ■ Touch Hold® (Fluke 77) ■ UL 1244 listed ■ Made in US.A. 73 - D.C. Voltage 0.7%, A.C. Voltage 3% Autoranging $150 ex tax - $175 incl tax 75 - D.C. Voltage 0.5%, A.C. Voltage 2% Autoranging with range hold, audible continuity/diode test $240 ex tax - $280 incl 77 - D.C. Voltage 0.3%, A.C. Voltage 2% Touch Hold® $325 ex tax - $379 incl tax tflc:r'l-:T_arN.# Also call us for Signal Generators, Power Supplies, Counters, and any other T & M requirement; Full range of Fluke/Phillps Accessories. T & M PTY. LTD. Call Tim Wortman the specialist Fluke/Philips Distributor TECH-FAST T & M PTY. LTD. 14B MAXWELL STREET, TURRAMURRA N.S.W. 2074 TELEPHONE: (02) 988 3865 FAX: {02) 988 3861 VINTAGE RADIO By JOHN HILL The gentle art of scrounging valves Although many valves can still be purchased new, they tend to be expensive and some types are no longer available. Scrounging and checking secondhand valves is therefore an important part of vintage radio restoration. Vintage radio and valves go hand in hand and to think of one will automatically include the other. For this reason, valves are a fairly common topic for discussion among vintage radio collectors. However, as far as some people are concerned, valves aren't worthy of conversation. To these antivalve types, the word "valve" often conjures up nightmarish thoughts of trouble, inefficiency, unreliability and shattered glass. To some extent all these corn- ments are true. Valves can be troublesome, they are very inefficient, not as reliable as some modern equipment and they certainly are fragile - particularly if dropped. But there is another side to the old thermionic valve and I believe that they are not as bad as some would make out. As far as the humble domestic radio receiver is concerned, nothing does a better job than valves. Solid state radios may be more reliable and more energy efficient Most secondhand valves from derelict radios will still work OK and are much cheaper than new replacements. In addition, it may not always be possible to buy certain valve types, so building up a good stock of secondhand valves is an important part of vintage radio work. 64 SILICON-CHIP but not necessarily better in performance. A good valve receiver takes a lot of beating. The valves used in valve radios also give relatively little trouble. As a collector of old radios, I know this to be correct due to the number of radios in my collection that still have the same valves as when I first acquired them. When it comes to a 40-50 year old radio that doesn't work, it. is more likely to be something other than a valve that is the cause of the trouble. Valve radios can work for 20 years or more on a daily basis without as much as a hiccup in their performance. Grandma's Radiola When I was a lad in short pants my grandmother left her 1936 5-valve Radiola console with us when she moved to Queensland. Grandma moving out was one thing but leaving her wireless with us was an added bonus. That old Radiola was in use for at least another 15 years before I left home in 1959 and it was never serviced during that time. My father did remove the chassis from the cabinet on a couple of occasions but only to remove dust from the dial hardly a serious problem. · Only eight years ago my brother took the old Radiola to its final resting place (the tip). Although rather dusty and shabby in appearance, the set was still working. What's more, to the best of my knowledge it was still on its original set of valves. Unfortunately, I wasn't interested in vintage radio at the time and I actually helped to load the old receiver onto the trailer that was to take it on its last journey. (Sob!). Resurreetion Radio The original vintage wireless specialists Our skilled technicians offer QUALITY repairs & restoration. We have a large stock of bakelite and timber radios fully restored and for sale. Valves, high voltage capacitors and other specialised parts available. Don't throw out "junk" like this. Receivers in this condition are a good source of supply for old valves and many other valuable components as well. If a valve works, it is worth keeping. ADDITIONAL SERVICES COPIES OF: CIRCUIT DIAGRAMS $5.00 SERVICE MANUALS $10.00 AVAILABLE FOR MOST MAJOR AUSl. MAKES FROM 1934 ONWARD WANTED - valves, radios, etc., purchased for cash. Call in to our showroom at: 51 Chapel Street, Windsor, Vic 3181 PO Box 1116 Telephone: (03) 529 5639 CHRISTIAN BUND MISSIQ~ ·J Re,atoting,f~%~e, M,n This photo shows just part of the author's valve collection. It's amazing the number of old radio valves that are still around, both new and used. Grandma's Radiola is just one of many radios with similar histories. My 9-valve Astor Concertmaster radiogram was still going five years ago at the age of 30 years. It too was in entirely original condition with the exception of a rectifier valve that blew a filament when the set was only a month old. Although I sold the old Astor some 25 years ago, I have known of its whereabouts until quite recently. The failure of a near new component (the rectifier in this case) is a characteristic not only of valves but a good many other electronic devices as well. If a valve is going to give trouble it will most likely break down quite early in its life. If it survives for 12 months without burning out, then there is every possibility of it working for a considerable time. In many instances, an old radio was banished to the shed or the tip not because the valves became weak or the set stopped working, but because it became shabby and no longer suited the decor of the room. In some cases, these discarded radios were still working reasonably well on their original valves. Generally speaking, most used valves from dumped radios will still work OK and are quite serviceable. No doubt some will be damaged, weak or faulty, but an incredible COUPON Please cut and send to: CHRISTIAN BLIND MISSION INTERNATIONAL, P.O. Box 5, 1245 Burke Road, KEW, Vic. 3101 Phone: (03)817-4566 D = Please send me further information aboot CBMl's work. As long as it is possible for me, I will help: monthly D quarterly D annually D to prevent blindness D to restore eyesight D to rehabilitate the blind Enclosed is my gift of$ _ _ _ __ _ D Mr/ Mrs; Miss, _ _ _ __ __ _ _ Street, _ _ __ City, _ _ _ __ _ ____ _l'OtStcode, ____ _ . SEPTEMBER1990 65 Radio valves became progressively smaller as time progressed. Whatever their age, all newly acquired secondhand valves should be checked in a valve tester or in a working receiver to determine their condition. Although all of these valves bur:r;it out long ago, they are just too interesting to throw away. The one on the left was the subject of a 1921 Australian patent. amount will test OK and still have a useful service life. Although most radio restorers would prefer to use new valves, they are not always available nor are they cheap to buy. Often, secondhand valves will be the only practical replacements. Derelict radios I have bought a considerable number of totally derelict radios that have been real bargains as far as their valves were concerned. When one pays a few dollars for a wreck with four or five near new 66 SILICON CHIP valves in it, he has done very well. Good luck has smiled on me this way on many occasions but I also believe there is a reason why so many old radios have perfectly good valves in them. During the war years there was little or no production of radios or radio components for the civilian population. After the war, large numbers of pre-war radios were given a long overdue service which, in many instances, would have included a new set of valves. For various reasons (perhaps the purchase of a more modern radio, radiogram or the coming of television), these reconditioned receivers had very little use and soon found their way to a dusty shelf in the back shed. There they sit until 40 years later I and other enthusiasts come on the scene and buy them at garage sales - still with their perfectly good valves. Another reason some old sets have near new valves in them is the fact that many homes had more than one radio. In those circumstances, the kitchen radio did 90% of the work while the lounge room radio may have only been used occasionally. In fact, I have a 1933-model console radio that still has its original valves and they all test as new. The cabinet is old and shabby but the set has been used very little during its life. Listening habits Listening habits were different 50 years ago compared with today. In the early days of radio, a receiver would be turned on to listen to a specific program and turned off when it had finished. Today, a radio (or a television set) is often left on all day whether anyone is listening or not. Also, the advent of television and portable transistor radios created a climate where the older valve radios fell from favour and were simply not used. Newcomers to vintage radio may wonder at what point a valve is considered serviceable and when it's not? As far as I'm concerned, a valve has to be really bad for me to discard it. There will come a day, when any valve in working order will be valuable. A valve tester is perhaps the easiest way of determining the usefulness of a secondhand valve. The tester measures the cathode emission and if emission is down, so will be the valve's remaining life span. A good valve tester will also check each individual basepin and can therefore pick up a faulty pin connection. An old hand at radio and TV repairs once told me that all a valve tester does is convince you that you ought to throw away perfectly usable valves. I don't believe that statement to be totally correct, but there is an element of truth in it just the same. ~ A valve tester can quickly indicate whether a used valve is near new, just about clagged or somewhere in between. When it comes to output valves and rectifiers, this information is worth knowing. These valve types need to be in good condition if a set is to perform well. One of the reasons for needing a good rectifier valve is that as the valve's efficiency (emission) drops, so does the high tension DC voltage. A radio never works well under these conditions and the usual consequence of reduced high tension is a considerable reduction in volume and general performance. What's more, if the rectifier valve is weak, there is a good possibility that the output valve will be in a similar condition and may also require replacement. Secondhand valve collections are likely to lack certain types of valves because some are more likely to fail than others. As previously stated, output valves and rectifiers are often rubbish bin material once their emission drops off. In addition, frequency changers such as the 6A7, 6AB, ECH 33-35, 6JB, 6KB, A valve tester, such as this Palec, is the best way of testing emission levels and checking for internal faults and short circuits. Valves can be tested in a working radio, provided of course that you have a receiver that uses the valve type to be tested. For serious work though, it's best to acquire a valve tester, particularly for checking rectifier and output valves. 6AN7 & 6BE6 etc are more likely to have faults than other valves due to their fairly complex construction. Battery valves are also in the high risk category due to their relatively short life and somewhat delicate filaments. Another point for the vintage radio collector to ponder regarding the use of secondhand valves is just how often will a particular set be used? Some of the receivers in my collection can go several months at a time without use and may be used for only a couple of hours over a 12-month period. Under such conditions - how good do the valves need to be? Are new ones justified when good used ones will work just as well? For all these reasons, a valve should really be on its last gasp before it is discarded. Nevertheless, secondhand valves need to be thoroughly tested, either in a valve tester or a working radio receiver. Valves are made to very close tolerances and the internal components are quite fragile. If valves are treated roughly or dropped, these internal components can become dislodged so testing valves is an important aspect of vintage r~dio restoration. Next month, we will deal with the various types of valves the vintage radio restorer is likely to encounter and discuss their applications. ~ SEPTEMBER1990 67 Attention ALL constructors, hobbyists and users of rack hardware. Manufacturer makes maior BOO BOO with huge shipment of rack cabinets. Massive ~savings of 40% and These are actual cases from our latest delivery of the famous Altronics rack case. They look fine don't they? Well then, what's the problem you ask? Why are they selling so cheap? • Firstly, the front panels were specified to be anodised. Instead, the maker has black powder-coated models H 0411 , H 0412 and H 0413 and silver alumadised the "natural" models, H 0401, H 0402 and H 0403. The actual appearance and finish is to a high standard and attractive. So what's the problem? Very simply, the majority of these rack cases are sold by our parent company, Altronic Distributors, to manufacturers and most manufacturers require (and insist on) an anodised finish to match with associated equipment when assembling rack consoles. • Secondly, the lid securing screws don't always line up perfectly - you occasionally might need to drill out a hole or two to get the screws to fit 100%. • In our view these deficiencies will not bother the average enthusiast (and perhaps quite a few trade users) and more than made up for with these fantastic savings. Sale Model HS 0401 HS 0402 HS 0403 HS 0411 HS0412 HS 0413 Finish Natural Natural Natural Btack Black Black Normally $59.95 $79.95 $89.95 $59.95 $79.95 $89.95 Once they're gone - 1-5 $39.95 $49.95 $59.95 $39.95 $49.95 $59.95 6+ $35.00 $45.00 $55.00 $35.00 $45.00 $55.00 that's it. Obviously we can't take any back orders in this instance. HIGH TECH Company Collapse Brings Fantastic Bargains for the Electronic Enthusiast *''V.1a te I'' (now D1scovery") · SENSATION! 11 UNBELIEVABLE VALUE/ Around $250.00 value for as low as $24.00! Altronics has recently purchased this quality stock from the liquidator of DTX AUSTRALIA LTD. You can use this equipment to gain limited access to the · ·viatel" information system. Each unit contains a Telecom approved modem and information decoding circuits. The single PCB is a goldmine of quality components for the enthusiast, Including the fantastically valuable SAA 5020 AND SAA 5050 chips. ALL STOCK BRAND NEW PREMIUM QUALITY INDIVIDUALLY TESTED BY THE MANUFACTURER Videotext PCB (Size 360mm x 150mm) Look at this list of component parts! VIATEL VIDEOTEX MODEM DECODER • Mains Transformer - 240-9/15/24V 300mA • Line Isolation Transformer - Telecom Four models to choose from; Each with a numeric keypad. approved 600/600 Ohm or 600/150 Ohm impedance. • Video/RF Modulator (Channel 0) e Low profile 12V SA SPOT Relay • Capacitor - 2.0uF 440V AC • Crystals - 6MHz and 4.43MHz e TTL, CMOS, Linear and LSI ICs - SAA 5020, SAA 5050, 2516 and many more • Voltage regulators • Bridge reciifiers • Trimpots and capacitors• Filter capacitors• Flatpack heatsink I Plus much, much more! X 1000 WITH RF OUTPUT X 1002 WITH RF OUTPUT AND TELEPHONE HANDSET X 1004 X 1006 WITH RF AND RGB VIDEO OUTPUT WITH RF AND RGB VIDEO OUTPUT AND TELEPHONE HANDSET • "Viatel" Is now "Discovery 40/80" 1 to 5 each 6 or more each $29.95 $34.95 $34.95 $23.95 $27.95 $27.95 $39.95 $31.95 NEW FOR SEPTEMBER SOLENOID OPERATED DOORLOCK Increases home security and garden privacy. Control your front door from lounge, kitchen or bedroom or anywhere you like. Comes complete with two face plates for either concealed or visible fitting. Premium (jrade (joocf for up to 1000 recfiarges! S4390$39.95 Charge rates: 45-50mA for AA, 20mA for AAA, ·' 10-15mA for 9V 120mA Normally 1-9 10+ AA 1.2V 500mAh $3.99 $3.25 AAA 1.2V 180mAh $4.50 $3.95 C 1.2V 1.8Ah $12.00 $10.50 D 1.2V MASSIVE4Ah$19.50 $18.00 216 9V 0.12Ah $18.95 $17.85 THIS MONTH 1-9 10+ $2.50 $2.00 $3.50 $2.90 $8.00 $7.00 $12.00 $10.00 $18.00 $15.00 FOUR DIGIT COMBO LOCK DESIGNED BYALTRONICS Yes! That's right, this four digit combination lock was designed fro m the ground up by the ALTRONICS R&D DEPARTMENT to exactly satisfy your security requirements. Ideal for use in alarm systems, solenoid operated doors and all systems requiring security access. K 1925 Features: • • • • • • • Single PCB construction Fits into standard GPO wall box Over 14 000 possible combinations 5 second combination entry time Code easily changed via DIP switches Latched or momentary output Optional battery back-up $39.95 Build your own security Audio Oscillator & Function Generator Fantastic Hi Tech - Hi Spee Saa EA Dec '86) This ultra low distortion oscillator is comparable with the best laboratory standard sine wave oscillators. As well as having very low distortion it has excellent envelope stability, square wave output and output metering. 1-9 $1.49 $1 .00 $4.00 $7.50 $3.95 10+ $1.25 $1.05 $2.50 $8.00 $5.85 ALWAYS f:t GREAT . VALUE Battery Operated Portable P.I.R. Intrusion Alarm Ward off thieves and intruders at home and when travelling This super handy, go anywhere P.I.R. alarm system is great for shop, office, caravan, boat, garage and whenever you are travelling. Extremely easy to install. Features: • Exit delay S5305 • Entry delay • Large coverage • up to 100 square metres • Low battery LED indicator • 9V Alkaline battery (not supplied) lasts many months $69.00 NEW THIS MONTH ANALOGUE-DIGITAL MULTIMETER Analog reading: 4.5" with 90' Arc scale, knife edge pointer and anti-parallax mirror. Digital reading: 3.5 Digit LCD, 0.5" high with Polarity and "LO BAT" indication Over range indication: 1/2 digit 1 ON, other digits OFF Power supply: 9V battery Low battery indicator DC Voltage: 200mV, 2, 20, 200, 1000V AC Voltage: 200mV, 2, 20, 200, 750V DC Current: 20, 200uA, 2, 20mA AC Current: 20, 20DuA, 2, 20, 20DmA dB Range: -20dB, OdB, 20dB, 40dB ,S.'!!:ll~r,itiiesistance: 200Q, 2kQ, 20kQ, 200kQ, 2MQ, 20MQ . ;,.IOil.,.I. Plus Audible Buzzer and Diode check Features: • Frequency range 10Hz - 100kHz in 4 r • Output level 3V RMS Max. adjustable • Attenuator Odb -10db, -20db, -30db, -40db, -50db plus fine adjustment • Output impedance -600W unbalanced • Output waveforms • sine and square wave All components mount on a single PCB. Kit comes complete with professional silk-screened and punched natural anodised aluminium front panel. K 2540 Normally $155 This month only $145.00 a 1090 $199.50 n ew u I es ers rom at Low Direct Import Prices Specifications For a 1066 / Q 1070 Engineering Multimeter Testers DC Voltage Range: 200mV, 2V, 20V, 200V, 1000V • Accuracy: All ranges+/- 0.5% rdg + 1dgt Input Impedance: 10M.n AC Voltage Range: 200mV, 2V, 20V, 200V, 750V lnputlmpedance: 10M.n , DC Current Range: 200uA, 2mA, 20mA, 200mA, 10A Z AC Current Range: 200uA, 2mA, 200mA, 10A Resistance Range: 200.n, 2kn, 20kn, 200kn, 2M!l, 20M.n, 2000M.n Capacitance Range: 2000pF, 20nF, 200nF, 2uF, 20uF Transistor hFE Base DC Current : 10uA, VCE: 2.8 +/- 0.4V General: Display: 3 1/2 dign liquid crystal wnh maximum reading of 1999 Overrange Indication: Highest digit of (1) or (-1) is displayed Q 1068 Carry Case $12.50 (suit Q 1066 & Q 1070) FREE with each multimeter ordered this month Multimeter with Temperature Meter, Capacitance, Diode and Transistor Tester Temperature Range: -20'C to 750'C 0' F to 1400'F Accuracy : +/- (3' + 1 dgt) up to 150'C +/- 3% rdg over 150'C +/- (15' + 2 dgts) up to 225'F Q 1066 $149.00 Logic Tester, Frequency Counter, Capacitance and Transistor Tester peec (ETI March '88) Here la a self contained Speech Synthesiser that does not require a computer to control It. This small, simple circ contains all the necessa components to make yo favourite possessions speak. can be connected to almost a appliance, vehicle or ho remote control system to let y know when the kettle h swnched off, the doors locked or the water in the r is boiling. 12 V DC operation. K 9500 complete with preprogrammed EPROM Normally $115.00 This month only $95.00 a 1010 $189.00 YOU SAVE $20.00 BUT ONLY IF YOU'RE QUICK! AVIATION HEADPHONES ~~gri~~~~~(~~7g7tn~~? k~~c 1: 2.4V Frequency~ange: 2kHz, 20kHz, 200kHz, 2MHz, 20MHz Input Sensitivity : 20MHz range 1V rms . Other ranges 35mV rms. Q 1067 Temp. Probe for Q 1066 $29.95 Why pay $400 or more for a David Clark set? BENCH AMP SIGNAL TRACER see EA April '88 Another Altronics Kit Special! AVIATORS HEADSET WITH OIL FILLED EAR CUSHIONS . • High performam:e, noise attenuating \ earphones. • Noise cancelling microphone • Cushioned head pad • Super sturdy • Great performance• Superb, professional pilot's headset will last a lifetime with reasonable treatment. • Includes standard aircraft jacks. Here is a simple but effective audio bench amplifier. Ideal for fault finding and experimenting and sooo inexpensive. C9010 ONLY $189.00 Features:• Input range 10mV to 10V in 4 ranges• Inbuilt speaker and external speaker socket • Overload indicator • Requires external 9- 1SV AC supply Now available from Altronics Dealers K 2100 Normally $65.00 FREE this month with each kit, K 2565 RF Probe kit worth $12.00 Polypropylene Bass Drivers Ultra Hig~ Power Capacity Our ALL NEW "Black" polyprop cone Bass Drivers exhibit quite astonishing low register reproduction. Power ratings quoted are conservative. Not the cheapest .but definitely the BEST VALUE we know of - ANYWHERE. 12" (300mm) WOOFER 10" WOOFER 60Watt RMS 100W Max. C 3065 100watt RMS 150W Max. C 3070 Massive 200 W Max. C 3075 Normally $99 Normally $129 NOW NOW ONLY Was $69.00 NOWONLY ONLY $99 $49.00 $89 YOU SAVE $30 8" WOOFER 60Watt RMS 1OOW Max. C3060 Was $49.95 Now$39.95 SAVE $10.00 Midrange 30Watt RMS SOW Max. C 3055 WAS $29 .95 NOW ONLY $24.00 61/2" Mid Range 30Watt RMS SOW Max. with sealed frame c 304s Was $27.50 NOWYOU SAVE AT$22.00 NEW! NEW! NEW! Another superlative design from the Silicon Chip design team. See SIiicon Chip Magazine July '90 The use of modern circuit technology Waveform Synthesis enables this Generator to deliver i performance specifications comparable to commercial equipment costing $2000 and more. £t .l ,, J This new Digital Sine/Square Wave Generator uses high speed CMOS !Cs and a dignal filter IC to produce sine and square waves over the frequency range from 1 0.1 Hz to 500Hz. tt also features a 4-digit frequency readout and an output level control. r K2547 $175.00 VALUE How many times have you opened up that favourite board game to find that s omeone has pinched the d ice? lry that caae, why not build th is elegant electronic d ice w hic h uaea j ust two CMOS !Ca? It simulates the ro ll of a real dice and even t urns ltaelf off. Build this elegant Specifications: Frequency range: 0.1Hz-500kHz in four ranges ; 0.1 -10Hz; 101000Hz; 1-100kHz; & 100-500kHz • Output wave forms: Sine and square • Harmonic distortion: Less than 0.15 from 0.1Hz-50kHz; 0.27% at 80kHz • Square wave riae time: 10ns • Square wave fall time: 10ns • Output level: Sine wave; variable from 0-1.2V RMS; Square wave; variable from 0.5V p-p • Output impedance: 6000 nominal • Load impedance; 6000 to infinny • Protection: Short circun protected (indefinite)• Display accuracy: +/-2% +1digit 4 separate channels-up to 30 seconds per channel record/playback time. This Digital Recorder deHver• utonl•hlng reproduction of voice and/or music without one •Ingle moving pert/ Electronic Dice LED readout simulates a "dice" - Great fun to build. see Silicon Chip July 90. Digital (X~l~~De!tfrCOrder , Build this for the kids! $29.50 Includes Jiffy box. The •peclficstion• of thl• excellent detlign compare very favourably with commercial te•t equipment coating $300 •nd more. A very worthwhile addition to your workbench. Digital Capacitance Meter "Silicon Chip" May '90 Superb test equipment. K2524 Here is a digital voice re;.,rder ihat -~an -~tore 4 different signals, voice, sound or a music source of up to 30 seconds each or one recording of up to 2 minutes. There are 4 trigger inputs so that a message can be retrieved when a certain condnion occurs. Battery backup is provided so that the messages are retained when main power is off. Typical applications Include: • Alarm system messages • Sales messages for customers put "on hold" • Experimental telephone answering machine • Door station announcer • Talking displays for shops • Emergency warning message announcement • Operation instructor for machinery etc. • Countless other applications where voice or music is required • $100's cheaper than i"llorted digital recorders K 9550 Kit complete - PCB Format K 9555 Kit complete - with Inst. case $120.oo ··ecapacitancc lpF to 9999µ!' in ,even ranges • Designed for laboratory and wirbhop use e Accuracy+/· 1%, +/- 1 digit e Mains powered Low Cost Dual Tracking Supply $129.00 For those who want a professional appearance - stand alone product, we can supply with our Deluxe H 0483 Instrument case and fully punched and screen printed front panel $149.00 Laboratory Power Supply Kit Over 500 sold to date! EA May ·as (See Silicon Chip Magazine Jan '88) Ideal for experimenting and prototyping with memory, logic and Op ampa. FEATURES: • Adjustable + or -1 8.5V at 1.7A e Voltmeter • Floating ground • Dropout indicator • Load sw nch • Compact, sturdy "ASS" instrument case K 3325 NOR MALLY $99 SEPTEMBER THIS MONTH ONLY SPECIAL $89.00 SAVE $10.00 • 3 to 50Volts at 5Amps • Single PCB - very easy to build • Floating output • Super low ripple voltage • High efficiency TOROID transformer is used K 330110 turn 0 /P control $29.50 $14.50 K 3302 +/-1 2V Aux. outputs For the engineer and hobbyist K3300 $ 195.oo 120 Watt Public Address Amplifier LCR DIGITAL MULTIMETER (See Silicon Chip Magazine Nov '88) h perlormance Low Noise P.A. Amplifier This truly fantastic LCR Digital Multimeter enables you to test a wide variety of components. lndispensible for the design engineer, technician and enthusiast alike. DC Voltage: Range: 200mV, 2, 20, 200, 1000V Accuracy: 0.5% + 1 Input Impedance: 10MQ on all ranges AC Voltage: Range: 200mV, 2, 20, 200, 750V Accuracy: (50-S00Hz: 0.8% + 4, 1.2% + 4(750V) Input Impedance: 10MQ on all ranges DC Current: Range: 200uA, 2mA, 20mA, 200mA, 2A Accuracy: 1% + 1(200uA - 20mA), 1.5% + 1 (200mA - 20A) AC Current: Range: 200uA, 2mA, 20mA, 200mA, 2A Accuracy: 1.2% + 4(200uA - 20mA), 2% + 4(200mA - 20A) Resistance: 200Q, 2kQ, 20kQ, 200kQ, 2MQ, 20MQ, 200MQ Capacitance: Range:2nF,20nF,200nF,2uF,20uF Max Input: 5V DC/Peak AC on all ranges Inductance: Range: 2mH, 20mH, 200mH, 2H, 20H hFE Test: 0- 1000hFE values either NPN or PNP transistor Plus Diode test NEW PRODUCT JUST ARRIVED! Q 1062 a t $149.00 represents a price break through. Carry Case Q 1068 $12.50 e BANKCARD e VISA e This professional quality Public Address Amplifier offers performance equal to or better than commercial units costing units costing twice as much. Amplijiers using 100V line output are used extensively in everyday situations where numerous speakers and long output lines are employed. Ideally suited for Halls, Churches, Clubs and even temporary setups. Inputs: 2 balanced microphones and 2 auxiliaries suitable for direct connection to CD player, tuner etc. Outputs: 4 Ohm, 8 Ohm or 100V line output configuration Power Output (RMS): 125 Watts into 4 Ohms; 90 Watts into 8 Ohms; 120 Watts into 100V AC line Frequency Response: 30Hz to 30kHz Input Impedance: 50k Ohm for line inputs (Aux 1, Aux 2), 600 Ohms for balanced microphones - 300 Ohms for unbalanced Normally $499.00 If you wanted it but couldn't afford it, now is your chance, K so20 microphones Harmonic Distortion: less than 0.3% from 20Hz lo 20kHz. definitely this month only $400.00 YOU SAVE $99.00 Credit Card Multimeter Fantastic for the glovebox, toolkit and, of course, your top pocket. A great gift·idea for the enthusiast. Specifications: DCV: 200mV, 2V, 20V, 200V, 750V ACV: 2V, 20V, 200V, 500V OHM: 200n, 2kn, 20kn, 200kn, 2Mn, 20Mn Includes continutty tester. Q 1060 MASTERCARD e $65.00 PHONE TOLL FREE 008 999 007 e NEXT DAY JETSERVICE DELIVERY Country clients please allow an additional 48-72 hours MORE AL TRONICS DEALERS WANTED If you have a Retail Shop, you could increase your income significantly by becoming an Altronics Dealer, Phone Chris Campbell (09) 328 2199 for Details. 174 Roe St. Perth W.A. 6000 PHONE TOLL FREE 008 999 007 Perth Metro (09) 328 1599 ALL MAIL ORDERS P.O. Box 8350 Stirling Street Exchange Perth W.A.6000 AL TRONICS RESELLERS Chances are there is an Altronics Reseller right near you - check this list or phone us for details of the nearest dealer. PI••• Note: Resellers have to pay the cost of freight and insurance and therefore the prices charged by individual Dealers may vary slightly from this Catalogue - In many cases, however, Dealer prices will still represent a significant cost saving from prices charged by Altronics Competitors. Don'tlorget our Expresa Mell and Phone Order Senrlce - for the coat of a local call, Bankcard, Vlaa or Mutercard holders can phone order for aame day despatch. Blue Ribbon Dealers are highlighted with a ■. These Dealers generally carry a comprehensive range of Altronic products and kits or will order any required item for you. STANDARD DELIVERY & PACKING CHARGE $5.50 to 1Kg $8 over 1Kg AUSTRALIA WIDE - We process your order the day received and despatch via. Australia Post. Allow approx 9 days from day you post order to when you receive goods OVERNIGHT JETSERVICE Up to 3 Kg is $8.00- 3Kg to 5Kg is $20.00- We process your order the day received and despatch via. Overnight Jetaenrlc• Courier for delivery next day Country areas please allow additional 24-48 hours. HEAVY HEAVY SERVICE -All orders of 10Kgs or more must travel Express Road - Please allow 7 days for delivery. $12.00 to 10Kgs, $15.00 over 10Kgs. INSURANCE - As with virtually every other Australian supplier, we send QOOds at consignees risk. Should you require comprehensive insurance cover against loss or damage please add 1% to order value (minimum charge $1). When phone ordering please request "Insurance". TOLL FREE PHONE ORDER - Bankcard.Visa, Mastercard Holders can phone order toll free up to 6pm Eastern Standard Time. Remember with our Overnight Jetaenrlce we deliver next day. COUNTRY ALBANY BP Electronics ■ 412681 ESPERANCE Esperance CommunicatioTis 713344 GERALDTON Bird Electronics 641631 KALGOORLIE Todays Electronics ■ 212777 KARRATHA Daves Oscitronic 854836 PORT HEADLAND Ivan Tomek Electronics 732531 WYALKATCHEM D & J Pease 811132 NT ALICE SPRINGS Ascom Electronics 521500 Farmer Electronics 522388 DARWIN Ventronics 480030 ACT CANBERRA Bennett Commercial Electronics 805359 VICTORIA CITY All Electronic Components 6623506 SUBURBAN CHELTENHAM Talking Electronics 5842386 CROYDEN Truscott Electronics ■ 7233860 PRESTON Preston Electronics 4840191 COUNTRY BENDIGO KC Johnson ■ 411411 MORWELL Morwell Electronics 346133 QUEENSLAND CITY Delsound P/L 8396155 SUBURBAN CAPALABAKingsway Electronics 3902399 WOODRIDGE David Hall Electronics 8082777 COUNTRY BUNDABERG Bob Elkins Electronics 721785 GLADSTONE Supertronics 724459 MACKAY Philtronics ■ 578855 ROCKHAMPTONAccess Electronics (East St.) 221058 TOOWOOMBA Hunts Electronics ■ 329677 TOWNSVILLE Solex ■ 7724466 MAROOCHYDOREMals El.ectronics 436119 SA CITY Force Electronic ■ 2125505 SUBURBAN BRIGHTON Force Electronics ■ 3770512 CHRISTIES BEACH Force Ele4tronics ■ 3823366 ENFIELD Force Electronics ■ 3496340 FINDON Force Electronics ■ 3471188 LONSDALE Force Electronics ■ 3260901 COUNTRY MT.GAMBIER South East Electronics 250034 WHYALLA Eyre Electronics ■ 454764 TASMANIA HOBART George Harvey ■ 342233 LAUNCESTON George Harvey ■ 316533 NSW CITY David Reid Electronics ■ 2671385 CARINGHAH Hicom Unitronics 5247878 COUNTRY COFFS HARBOUR Coifs Habour Electronics 525684GOSFORD Tomorrows Electronics 247246 GRAFTON East Coast Electronic 431250 NEWCASTLE Novocastrian Elect.Supplies 621358 RAYMOND TEi'IRACE Alback Electronics 873419 WINDSOR M & E Electronics 775935 WOLLONGONG Newtek l:lectronics ■ 271620 Vimcom Electronics 284400 WAGGA WAGGA Phillips WA The risk of passing the buck The more complex our technology becomes, and the more specialised the services needed to keep it working, the more risk there is that. one specialist will pass the buck to another while the customer gets little or no service. It's something we need to watch. Something like that could have happened with the story I'm about to relate. The fact that it didn't was due to a number of factors; the honesty of a colleague, the patience and understanding of the customer, and what I like to think of as a policy of attention to detail on my part. And if that last remark sounds at all self-righteous it is not meant to be. It is no more than good business practice; the kind one needs to stay in business. Anyway, enough of the philosophy, let's get on with the story._ It started about 18 months ago and mvolved one of my long standing customers who owns a Thorn 63TI colour TV set. This set uses an AW A "Q" series chassis and is about 6 years old. Also important is the fact that he lives on an escarpment overlooking the sea, in one of our southern seaside suburbs. And in certain conditions, he cops a lot of salt spray; something which plays havoc with all metal fittings from door hinges to TV antennas. The site, in the TV sense, is a bit of a mixed bag. To the north, in the direction of the local VHF transmitters, it is quite severely shielded. In fact, he just about gets by. On the other hand, he has a clear path down the coast to the south. UHF channels It was for these reasons that he pondered the possibility of being able to receive the UHF transmit- 74 SILICON t.HTP ters then being set up to the south of Wollongong. One attraction here was the fact that major sporting events are often blacked out in Sydney but are available from outof-town transmitters. In fact, a number of clubs were then installing eleborate UHF antennas so that they could receive these sporting events from Wollongong. I was also aware that other viewers in this general area, in favourable locations, were receiving quite acceptable signals. So when he put this idea to me I agreed that it might just work. But I do very TETIA TV TIP Philips KT3A·1 chassis Symptom: Set hiccupping. Both line output transistor and tripler ~ere changed, without any success. E-W diodes D562 and D567 were removed for checking, and the fault was found as they were being replaced. Cure: Dry joint at the earthy end of C567, where it joins with C562 and the two E-W diodes. It's hard to see why this fault had such a dramatic effect but obviously the circuit relies on the full capacity of C562 being present. TETIA TV Tip is supplied by the Tasmanian branch of The Electronic Technicians' Institute of Australia. Contact Jim Lawler, 16 Adina St, Geilston Bay, Tasmania 7015. little antenna installation work these days; just keeping the workshop running is a full time job. Instead, I normally refer such work to one or other of my colleagues who specialise in antenna installation: field strength surveying, selection of antennas and the erection of suitable masts. So my colleague duly visited the site and made the survey. The results were a bit "iffy", and my colleague advised against making an immediate decision. Not all the transmitters were yet running at their full authorised strength and he suggested waiting until the whole system was up and running. The customer was happy enough to accept this advice but suggested that, while he was there, my colleague give the existing VHF antenna and coax a general overhaul. This was duly done and involved little more than a general clean-up and the securing of some loose coax. After that, all went well for a few weeks until the customer complained to my colleague that performance on the VHF channels seemed to have deteriorated somewhat. My colleague went back, checked the antenna mechanically, then made another field strength measurement. This produced figures similar to those taken before; in other words it was not an antenna problem. So was it the set? He didn't feel competent to make a firm decision on this but a rough check suggested that the set might be a bit down. It produced an acceptable picture when fed via the owner's video recorder (due to the extra gain of the recorder) but was quite poor when fed directly from the antenna. So the ball landed back in my court. I try to avoid house calls as far as possible these days but this was clearly a case where the pro- blem had to be assessed on the spot. So armed with my own field strength meter, I made the call. And my findings seemed to tally with my colleague's; signals from the antenna were about what I would expect but I had to admit that the overall performance seemed more marginal than previously. I offered to take the set back to the shop and give it a complete check but the owner elected to let things stand for the present; he could get by and had some programs he wanted to be sure of seeing. So we left it at that for the moment. Snow & confetti A few more weeks went by and then there was another call for help. It was no marginal situation this time; for all practical purposes all signals had been lost. So I made another call. And he was right; there were just some faint images behind a curtain of snow and confetti. Fortunately, I had taken the field strength meter with me again, otherwise I may have gone off on a false trail. Because, although it looked like the set was at fault, it was really the antenna. So what had my colleague done wrong? Nothing really. I noticed that the customer had a team of painters on hand and, in answer to my query, he realised that the signals had been lost about the time they started work. I went outside and took a closer look at the coax. This comes in under the eaves from the mast, runs down the wall where it is held by a series of nail-in clamps, and then runs under the house and up through the wall cavity to an outlet in the lounge room. And the painters, in their enthusiasm, had pulled the cable away from the wall - by the cable itself apparently - in order to make a smooth paint job. They'd also made some attempt to put it back in place but it was a clumsy effort and all too obvious. The result was equally obvious to the ohmmeter; the cable was open circuit. So my colleague was called back again and a new run of coax fitted. That put everything back to more or less normal but it had all been a bit of a circus. Privately, I hoped that that was the end of it. But it wasn't. Several weeks went by and then came another call for help; the system had dropped its bundle again. The owner had been in two minds whether to call me or . my antenna colleague but finally chose me because he felt that the antenna had been so thoroughly worked over that it had to be the set this time. And he was right. I took my field strength meter along and quickly confirmed that the antenna was doing its job. So it was the set and my first reaction was that it was probably a tuner fault. In any case, it was not a problem I was prepared to tackle in the customer's lounge room so I loaded the set into the van and took it back to the shop. On the bench I made a few routine checks and I was contemplating what to check next when I suddenly had an impulse to check the AGC trimpot setting. It wouldn't be the first time that I have found that, for one reason or another, this setting is less than optimum. And in any case, the set's behaviour when this is adjusted can sometimes produce a few clues. Anyway, I slipped a screwdriver into the slot and exerted gentle pressure in an effort to turn it. And that was all it took. The set suddenly burst into life and produced a bright snow-free picture with all the indications of maximum sensitivity. Further tests confirmed this the only fault had been a dead spot on the AGC trimpot. I was a little surprised at this because it appears to be a quality component, with the track on a ceramic base, and very well made all round. It was only much later that the full significance of its failure became apparent. For the moment it was a simple replacement job, although I didn't have the exact type available. The closest I had was of similar quality and fitted physically. So the set was back home in a few hours and it hasn't missed a beat since. Shoving ducks That, technically speaking, is really the end of the story, although there is more to come on the same theme. But the point I hinted at SEPTEMBER 1990 75 SERVICEMAN'S LOG -CTD earlier is worth some attention. This is the risk of confusion and buck-passing when, as in this case, a service problem has to be split two ways. It is all too easy for an antenna technician to duck-shove a difficult situation by blaming the receiver, or for the serviceman to do the same by blaming the antenna. That simply leaves the unfortunate customer as the meat in the sandwich. And it has happened, as I'm sure some of my readers could testify. Fortunately, in this case, we know each other and respect each other's work. Which is how it should be. But to get back to technicalities, as I said that was the end of the story as far as that set was concerned and I soon forgot about it. Then, a few weeks ago, another set fitted with a "Q" chassis, an AW A C5319, landed on the bench. This was a later model but uses essentially the same chassis. And it also came from a site on the edge of a bay where it was subject to salt spray contamination, although the significance of this as.caped me initially. The complaint was partial frame collapse, the picture being only about two thirds normal height. I slipped a screwdriver into the height pot to make an exploratory adjustment - which can often reveal a lot about this fault - but got no further than exerting a minimum of rotary pressure. Then the picture collapsed completely and it took a deal of fiddling to get it back again - and then only with a setting that gave gross overscanning. Naturally, it was the trimpot the same type of pot. which had failed in the set in my first story. But that was not all. Having replaced the pot. and set up the height correctly, I decided a smidgin of linearity adjustment might be appropriate. But this pot. (another of the same type) turned out to be so jumpy as to make the job impossible. So that pot. was also changed. That was the end of that story. But a couple of weeks later another "Q" chassis (an AWA C5328 just out of warranty) appeared from a customer who lives almost opposite the owner of the set I have just described. His problem was poor sensitivity; the picture quality had become progressively worse over the last couple of months, until i~ was now virtually unwatchable. He had called in my antenna colleague, who had made a field strength reading, pronounced it normal, and then confirmed this with a portable set which produced a normal picture. So it was over to yours truly. The proverbial dog A quick check confirmed that the set was as sick as the proverbial brown dog but I had more than a gut feeling that I knew what was wrong. Sure enough, as soon as I touched the AGC pot. the set sprang into life. I replaced the trimpot, adjusted its setting, then checked the height and linearity trimpots on spec. But they were OK, so that was the end of episode number three. Episode number four involved an AWA C5324 "Q" chassis, and happened only a week or so ago. It came from the same general locality, was also not long out of warranty, and was another case of partial frame collapse. I replaced the height trimpot, then checked the linearity pot. It was also jumpy, so I replaced that as well. Having set up the height and linearity, I realised that there was a colour balance or grey scale problem. This turned out to be due to incorrect setting of the G2 pot. in the green gun. This, in turn, was due to yet another of these pots. which had gone erratic. So that too was changed. All the others seemed to be OK. So there we are; four sets and seven trimpots, all from a salt laden area. Which is significant because I cannot recall ever having had any other trouble with these pots in other areas - and a goodly number of "Q" chassis have passed through my hands over the years. It simply means that these trimpots, reliable as they are in most environments do not like to be beside the seaside'. She'll be right mate --..11 ~-"'.::,i;...;:_ 76 SILICON CHIP And now for a change of scene, here is an incident related to me by a colleague from the Illawarra district, south of Sydney, which is slowly being changed over to the UHF TV system. And although he relates one particular incident, he stresses that it is becoming an increasingly common one. This is how he tells it. This story concerns one of my customers from way back who purchased an AW A video recorder (model AV52), although I hasten to emphasise that this is no reflection on AW A. It could just as easily have been any brand you like to nominate. It is also important to add that this customer lives some distance out of town in a poor UHF signal area and this compounded the problem somewhat. On the other hand, he did have a good antenna set-up, covering the local VHF channels, the Sydney commercial VHF channels, plus a recently installed UHF array. It all started about a month before I came on the scene, when this chap had bought the recorder, as a result of a "special offer" by an out-of-town outlet. It was one of those transactions where the recorder was simply handed to him in its sealed carton, with the salesman's assurance that he would find all the necessary instructions in the manual inside. In TV TEST EQUIPMENT (AUSTRALIAN MADE) SHORTED TURNS TESTER Built in meter to check EHT transformers including split diode type, yokes and drive transformers . $78.00 + $3.00 p&p HI-VOLT AGE PROBE Built-in meter reads positive or negative 0-50kV. Can also be switched to check negative voltages. For checking EHT and Focus voltages as well as TVs and Microwaves. Hi-tension voltages. $98.00 + $5.00 p&p LOW-VOLT AGE PROBE Ideal for checking microwave ovens and TVs. The ~ ranges are from Oto 5kV and from O to 1 OkV. Double insulated for safety. $79.00 + $5.00 p&p m happening. From his attempts to explain it I gained the distinct impression that, with the VCR in circuit, he could not even get normal reception on the TV set. And as for signals via the VCR's tuner, the best he'd managed was a couple of snowy pictures but he wasn't even sure which channels they were from. The only thing he was sure of was that the so-and-so VCR was no so-and-so good and he reckoned that it ought to be fixed under warranty. Which was fair enough if the thing was crook. So I said, "Bring it in and let's have a look at it". I was quite prepared to find that he couldn't get signals through the VCR into the TV set. It is not the first time this has happened. A faulty splitter amplifier would be the most likely cause. But that was only a figment of his confusion. On the bench the recorder performed perfectly as a link between the antenna and a bench set. On the other hand, trying to get signals through the recorder's tuner into the TV set which I guess was what he had other words, "she'll be right mate". Well, this bloke took it all home and poured over the manual. But we all know about manuals, don't we? They make beaut light reading after you've worked out - or been shown - how to use the device. He did manage to work out the connections between the antenna, the recorder and the TV set. Then he tackled the job of setting up the VCR tuner etc. And this is where it all went horribly wrong. It was quite an undertaking anyway, because he was aiming for five UHF channels, two local VHF channels (4 & 5A), plus the three Sydney VHF commercial channels (7, 9 & 10). That can be quite an involved job even when you know what you're doing; it can be positively frightening the first time around. The end result was - not to put too fine a point on it - what one of our politicians would call "a monumental screw-up". And so he was on the phone to me. And such was the order of his confusion that he was unable to give me a clear picture of what was ANTRIM TOROIDAL TRANSFORMERS QUALITY TOROIDAL POWER TRANSFORMERS, MANUFACTURED IN U.K. NOW AVAILABLE EX-STOCK AT REALISTIC PRICES. General Construction Ou1£A tNSUl,.IION OUllll WINDIIIIG - DEGAUSSING WAND Strong magnetic field, larger than usual coil with multicore centre. Double insulated for safety with momentary switch operation. 240VA/C 2.2 amps. As important as having a soldering iron! $75.00 + $10.00 p&p TUNER REPAIRS We repair most tuners on an exchange basis. From only $17 .00 + p&p The Largest ex-stock source of toroidal power transformers in Australia. Models available to suit most project kits. Specials made to order. Enquiries from resellers and manufacturers welcomed. Quantity and tax exclusive prices available on request. Call for data sheets. Cheque, Money Order, Bankcard or MasterCard -:T.V.TuNERs) 216 Canterbury Road, Revesby, NSW 2212 Phone (02) 77 4 1154 HARBUCH ELECTRONICS PTY LTD 90 George St., HORNSBY NSW 2077 Phone (02)476-5854 SEPTEMBER 1990 77 SE:\J~N "'t~IM'POTS F\L.L FROM ~ .SAl--r LAOE-N been trying to do, to confirm that the tuner settings were correct revealed a hopeless mess, even from my antenna which delivers quite adequate signals. He had managed to get close to a couple of channels; close enough to lock the picture but nowhere near close enough to make the best use of the much weaker signals at his place. But the real gaff was that he thought he had tuned in the two local VHF channels, whereas he had actually tuned in the UHF channels which were relaying these programs. Verily and forsooth, confusion had reigned supreme. I spent about 20 minutes setting up all the channels he wanted, which gives some idea of what's involvE;Jd, considering that I didn't have to work it out from the manual. The result was pretty good, though I doubted whether he would do as well at his place, and I warned him about this. Then, with this thought in mind, I made some sensitivity checks on both the VHF and UHF channels. I've been caught before this way on nBw equipment. There's seldom much wrong with the VHF side but UHF is a cl.ifferent matter. The sen- P.:RE;.A sitivity of the tuner can vary greatly, even from set to set of the same model. So a set which appears to be OK in a good location may be quite useless in a lesser location, even though another such set will perform well. So the only sure answer is to measure the sensitivity. In this case, the readings were good so I felt that the client would get about the best results possible from his set-up and location. It must have been good enough, because he was quite happy with everything the next time I saw him. Philosophical reflections It's not always like that. Sometimes UHF performance on a new TV set or recorder is way down, in which case it should go back to the firm concerned. On the other hand, it is sometimes only marginally down and that makes it hard. In such cases, I usually find it difficult to get much satisfaction. There will be excuses, arguments about equipment accuracy, and much buck passing. The whole exercise can be very time consuming and seldom very satisfactory for the customer. So I am more or less forced to ig- .1.m:.,.;. ri:.~:i:.11~ RCS Radio Pty Ltd is the only company which manufactures and sells every PCB [, front panel published in SILICON CHIP, ETI and EA. 651 Forest Road, Bexley, NSW 2207. Phone (02) 587 3491. 78 SILICON CHIP nore it unless there is a very strong case. Yes, I know it's not fair but that is about the state of the art, UHF wise, at the present time. As for this exercise, the only slightly sour note was the need to charge for my service. In fairness to the company concerned, I could not claim for repairs under warranty. There was nothing wrong with the recorder; just the client's inability to set it up. I did keep the charge down to a bare minimum and he didn't complain. But my original dig at the salesman, the read-the-manual she'll-be-right-mate type, still stands. What happened wasn't the client's fault. It is ridiculous to expect the average bloke in the street, skilled handyman though he may be, to tackle a job like this, even with a good manual - and I've yet to see one of these. More to the point, this was not an isolated incident. More and more I am being called on to set up VCRs and TV sets which people have bought in similar circumstances. Most of them have no idea that any setting up is involved. They fondly believe that they can take it home, connect power and an antenna, and it will bring in all the stations. When it doesn't, they imagine, as did this client, that there is something wrong with it. And not all of them are so philosophical about paying for the job. So what's the answer? Should such specialised equipment be sold without adequate installation backup? Granted, it probably means an attractive first cost but much of this is lost if the buyer has to call in a serviceman to get the thing working. Nor is it fair to expect the manufacturer to carry this cost via warranty. After all, the retailer's mark-up is supposed to cover this service. So I suppose it's a case of "buyer beware" but that doesn't seem quite fair either. Well, that's my colleague's story and it offers a sobering insight into TV problems outside our city areas. My colleague also had quite few remarks about the problems being encountered in establishing the UHF service. I might encourage him to expand on this in a later issue. ~ AUSTRALIA'S DYNAMIC ELECTRONICS MAGAZINE They said we'd go broke but we didn't! Did you have doubts when we started SILICON CHIP? Many people shook their heads and said we were headed for disaster! It may not seem all that long ago but it's now almost three years since SILICON CHIP came onto the scene. According to most people, we had NO chance at all of succeeding. To tell the truth, we probably were a little foolhardy but we started off anyhow. We thought there would be enough readers out there who would appreciate what we were trying to do. Thankfully, enough of you have made the decision each month to buy SILICON CHIP for us to survive and grow. Our special thanks to those readers who took out a subscription in our early days - they helped us enormously. In fact, they probably made the difference between our survival and failure. So now it's three years down the track. You might have noticed how the issues have been growing, bit by bit, starting first at 96 pages, then 104, then 112 and now, with this issue, 124 pages and with a growing colour content too. 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C) TOTAL $A ~ z m Enclosed is my cheque/money order for$ _ _ _ _ _ __ or please debit my Card No. O: VJS4 in . [(- elo i.....l Mr/Mrs/Ms: _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Address:. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Card expiry date Signature, _ _ _ _ _ _ _ __ 80 _ _ _ _ _ _ _ _ PQStcode:. _ _ _ _ _ _ __ 24 Hour Fax Service Subscription Hotline (02) 979 6503 Send the coupon with your Credit Card Details. 24 Hours, 7 Days a week. Telephone (02) 979 5644 9am-5pm Mon-Fri and quote your Bankcard , Visa Card or MasterCard No. and expiry date. SILICON CHIP Detach and Mail to: FREEPOST 25 SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROY BEACH NSW 2097 No stamp required in Australia SPRING INTO OATLEY WANT TO MAKE A MINIATURE NIGHT VIEWER? MASTER SLAVE SWITCH EA JAN 90 HE-NE LASER WITH D.C. POWER SUPPLY These two major components, the Image Intensifier tube, and the 12kV Power Supply are very small! Tube Dia = 28mm , Length = 42mm. Power Supply Dia = 15mm, Length = 42mm. Power required is a 1.3V mercury cell but it will also work from a single 1.2V Nicad cell! OVERSEAS YOU COULD EXPECT TO PAY $3000 FOR A SECOND HAND NIGHT SCOPE, USING THESE TWO COMPONENTS. THE PRICE? ONLY $630 FOR THE PAIR: Power Supply and In verter! Incredible Value! Very limited Quanity. Remotely switch your non remote TV off and on via your remote controlled VCR. Can also be used with hifi systems, computers, etc. One switch operation. Mains filter and overvoltage protection included. ON SPECIAL: Complete PCB and all on board components kit. ONLY $24.90. AT THIS : PRICE YOU COULD • JUSTIFY IT'S USE , JUST AS A MAINS FILTER! Not a kit, a complete unit. Includes a laser head with a beam shutter, a matching power supply and instructions. Ideal for levelling , sights, effects, scientific experiments, hollograms etc, etc. Power: 0.7 to 0.95mW maximum. DC Power Requirements: 10-14V 1A ONLY S309.00 ••••••••••••••••••••• ············~·· ! * BE QUICK TO SECURE THIS PORT ABLE •• "POWERHOUSE' BARGAIN*** •• * * * DC POWER SUPPLY FOR HE-NE LASER TUBES This high quality American power supply will power all our tubes, including the 5mW tube. This is not a kit, it is a high quality commercial product. Input Voltage : 10-HV DC Input Current: 600mA to 2A Output Voltage: 21 OOV DC ±500V Trigger Voltage : 1OkV Dimensions: 90 x 38 x 25mm Weight: 160 grams Output Current: 4-6mA The actual output current is programmed by a single low wattage resistor, or a potentiometer. Instructions included. LOW INTRODUCTORY PRICE $209.00 BRAND NEW HE-NE LASER TUBES AT VERY SPECIAL PRICES 0.5-0.BmW . .... . .. $129.90 1-1.3mW ... . .. . . . $149.90 PLUS OUR CURRENT SPECIAL PRICED TUBE 5mWHE-NE TUBE WITH A 20,000 HOUR LIFE FOR ONLY $259. 90 USE IT FOR DISCO, AND STAGE EFFECTS, SURVEYING, ETC, ETC. WE ALSO HAVE AVAILABLE SOME UNUSUAL AND LOWER PRICED LASERS P.O.A. g Complete LASER KIT with 0.5 to O.BmW Laser Tube. ONLY $239.90 Complete LASER KIT With a 1 to 1.3mW Laser Tube. ONLY $259.90 THIS IS A MAINS POWERED KIT AND DOES /-' HA V E S PECI A L •· -' CONDITIONS OF SALE. Please contact us before -~ sending any mail orders. Proof of age is required. 0 ~ - OATLEY ELECTRONICS PO BOX 89, OATLEY, NSW 2223 Telephone: (02) 579 4985 Fax No: (02) 570 7910 Certified p&p $ 4-$6 Aust: NZ ·add $ 2. Distributors : slightly higher prices may apply. S EPTEMBER 1990 81 RE.MOTE CONTROL · By BOB YOUNG The care and feeding of battery packs Sooner or later, everyone involved with remote control realises that without good batteries, a fancy model is a dead duck. It is particularly unfortunate if the battery dies when your model is in mid-flight. The heart of the modern R/C system is the battery pack which, nowadays, usually consists of rechargeable nickel-cadmium cells. Statistically, the battery is now the number one killer of R/C systems and it is the very first item that I check on systems in for repair. That is not to say that nicads are unreliable far from it. But modern R/C designs and the components in them have become so reliable that the nicad is now the weak link in the system, primarily because of its inherent corrosive nature. However, there is a more obvious :reason why nicads have become the number one problem: they are prone to operator error and I mean operator error in a big way. Because any discussion on the care and feediR-g-of nicads is so vast, I intend to cover only the more obvious problems that present themselves to the R/C modeller. Operator error I define operator error as the inappropriate choice of cell type and the actual handling of those cells once installed. To begin, they must be recharged correctly and let me tell you it is unfortunate that the most popular fly82 SILICON CHIP ing time is Sunday morning. This means that the batteries must be recharged on Saturday night. Now strange things happen to human beings on Saturday nights, amongst which they stay out late and drink too much of that frothy brown liquid. If recharging is remembered at all, it is often in the early hours of the morning, resulting in a charging period well short of the required 1 O to 14 hours .. More seriously, the model · is usually banned from the nice warm house by a long suffering better half, and recharging often takes place in a cold garage. This further reduces charging efficiency and cell life. Sunday morning thus sees the R/C junkie, desperate for his weekly fix of fun in the sky and sun, drag himself out of the cot, thoroughly unsure of his position in the world and the state of charge of his batteries. In trying to relate to his position in the world he probably falls back on that good old Australian question: "Did I have a good time last night or what?" As he most likely cannot remember he p:roba bly consoles himself with that equally famous Australian reply, "Gawd I feel crook, so I must have". Unfortunately there is no such simple way to gauge how the nicads fared, short of doing a timed discharge and recharge, which will not help get our R/C desperado to the flying field in time for that contest. So, reaching once more for another Australianism, he sets off with a "she'll be right mate". A trifle facetious perhaps but this is a scenerio that I have encountered many times in my career in the field of R/C modelling. Of course, few customers have the courage to admit it but some have. I have done similar things myself and although I have never partaken of · the amber fluid, my desperation to fly has certainly overridden commonsense on occasions. And yes, I have forgotten to recharge my batterie·s once or twice. Access to a good power supply allows a rapid charge but the average modeller has no such recourse and will often in desperation fall back to the "she'll be right" panacea. The lessons learned are usually bitter ones and age and experience soon teaches one to put batteries on charge before one goes out on Saturday night. However, there are always new chums arriving in the hobby and the same mistakes keep re-appearing. Different batteries The modern nicad battery, along with all modern electronic components, has suffered from the process of proliferation. The result is a bewildering array of components with very subtle differences in the local hobby stores. 1.6 - - - -- ..-------r- - - r - - - - r- - -, w "'et ~ 11---+--+-- -+- --+--+-t+--+~ > -' -' ~ o.8 1-- ......L---'----+-- -tt,8C,---,";;4c-t~,c:.--:o:-l.2:lc 0.81--- CNARGE : 0.1C x 16Hr DISCHARGE : 0.2C, 1C, 4C, BC TEMPERATURE : 2o·c 0·6 L _ _2_0 _ _4_0_ __.. &o- - ~ 80~ - ~ 10-=o-~ 120 0 -1-- -+ - - - + - - - + -----+------1 0. 2 DISCHARGE CAPACITY (¾) _ 6===:::l::=N!;,; i·Cd~IN::::TE::RN=:Al:::,R:r:ESl:S:TA:NC::: E±== = ;= 0 60 ==---! 60 Fig.2: the effects of discharge current on cell efficiency. Note that a discharge current of 4C results in the efficiency dropping to about 90%. The output voltage is also reduced along the entire discharge curve. DISCHARGE TIME (HOURS) Fig.1: one of the dangers with nicads is the sudden voltage drop at the end of the discharge curve. There are fast charge, low discharge rate batteries; slow charge, high discharge rate batteries; calculator batteries; torch batteries; portable radio batteries and dozens or perhaps hundreds more. What does it all mean and more importantly, which one do I use in my R/C set? To answer this, we must have a very clear idea of what the batteries will be called upon to cope with in the locations in which you intend to use them. In this month's column, we will confine the discussion to the transmitter and the receiver battery packs. A later column will discuss the more demanding ultra high discharge rates encountered in electric powered aircraft and cars. This discussion will cover the construction of different cell types as well. In the R/C transmitter (Tx), the current consumption is usually a steady 150mA or thereabouts, depending primarily upon the Tx's power amplifier stage. Therefore, the demands on the construction of the battery are low and most lowcost 500mA.h cells will do the job nicely. In my opinion, based on 2 7 years of dealing with nicads, the overriding factor is the quality of the cell construction and the safety chemicals included to provide overcharge protection. A good quality cell will provide around 10 years of trouble-free service in the transmitter. But "black wire" syndrome is the big problem and periodic inspection is a must, even with high quality cells. For a detailed discussion on the "black wire" syndrome, see the February 1990 issue of SILICON CHIP. The manufacturers' instructions often point out that battery boxes are not recommended and if used they must have nickel or nickel plated steel terminals. Copper, zinc, aluminium and chrome will readily corrode. Even nickel terminals will still tend to oxidize and must be wiped clean regularly. A spray of CRC-226 helps minimise this effect. This effect is one of the great mysteries in using nicads and the major cause of failures. Manufacturers go to great pains to point out that the cell is sealed and that it can withstand the normal 50mA charge for extended periods and yet the cell still promotes corrosion both on contacts and on circuit boards in the near vicinity. Modellers rarely clean the contacts or check for "black wire" or other signs of corrosion until some catastrophic failure occurs. I feel that Tx batteries should be charged out of the Tx case if possible. I still have yet to see a satisfac- tory explanation for the "Black Wire Syndrome", yet this problem can eat the negative wiring loom right out of electronic equipment and is a major source of device failure. The position for the receiver battery is vastly different. A servo at start up will draw an instantaneous current which may be as high as one amp. More usually this figure runs at 600mA. Thus, four servos leaping into life simultaneously will draw 2 to 3 amps which is quite a load for a 500mA.h battery. Helicopters The position in a helicopter is by far the most demanding, for several reasons. First, modern helicopters require around six servos plus a gyro. Second, the helicopter has almost no natural stability and therefore must be flown constantly. Thus, the servos rarely rest and as a result, current consumption is very high. The situation in a model car is not as critical for two reasons: first , most cars run only two servos and second, the car can be stopped im- 1.4 1.3 > w "'et 1.2 = C > -' -' w '-' 1.1 CHARGE : 150mA (C/3.3) x 5Hrs. TEMPERATURE : zo•c ~ ~- i--.....- \ " 1A (2C) 20 - "'I \ 250mA\ (C/2) 500mA' (1C) 40 60 80 DISCHARGE TIME (MINUTES) 100 120 Fig.3: voltage curves for a consumer-type cell at C/2, C & 2C. Note the rapid voltage drop at the endpoint in each case. SEPTEMBER1990 83 Now the important point is that the voltage drop across the batteries at these high currents can be considerable in cells not intended for high discharge rates. This results in supply rail noise finding its way into the Rx and decoder circuits, reducing range and causing excessive servo jitter in weak signal areas. In fact, the situation can very quickly deteriorate into a closed loop with the supply rail spike generated by the servos starting causing a decoder fault which will in turn cause the servos to start again, thereby re-injecting another spike and bringing about complete loss of control. The Rx battery, designed for low current operation, virtually collapses under a constant 2-3 amp load and the model is by now irretrievably out of control. I shudder when I open some sets to find cheap calculator nicads, usually designed for 50mA constant current load. Cells designed for high current usage have end welded plates and other features to reduce internal resistance and thus internal heating. High rates of discharge will reduce cell life even in cells designed for this usage. This is one very good reason for using the largest capacity battery weight will allow. I refuse to guarantee the repair unless those cells are replaced, for I know from past experience the set will be back soon. Unfortunately, this time I will be blamed because I was supposed to have fixed it. In ..:;- 3 0 0 1 - - + - ' - . . + - ~ - - - - + - - - - - - - t ~ g 250 l---+--+-.......-1----+----,f----l ~ ~ l!; 2001---+--f->'---'lr----+-----,f-----t ~ 1501---1---1---i.:::o..,---'",d-----,f-----t w d ► "' 1001---i--+--l---+-~i-=--... 0 10 20 60 40 100 80 DEPTH OF DISCHARGE, DOD(%) Fig.4: depth of discharge (D.O.D) vs. cell life. The graph shows that the deeper you discharge the cells, the lower their cycle life. mediately the first signs of trouble show up. It takes time to land an aircraft and often that time is just not available because of the very sharp "knee" on the voltage curve. A 500mA.h pack will give about 2.5 hours in a 4-servo aircraft but only about 45 minutes in a 4-servo helicopter. The usual pack size for helicopters is 1.2Ah. There is an important point to note here. Modellers tend to learn from experience that a 5-hour charge is enough for, say, four flights; the industry rule of thumb being one hour of charging per flight. What can happen is that a windy day calls for more control inputs and thus higher current consumption and the reduced charging time resulting from our late night out (referred to above) is just not sufficient. The result may be a crash on the last flight. 100 80 ' -r--- ---- the R/C world, once you have repaired a set, it seems that you are held eternally responsible for that set. I used to joke that even if the wings fell off the aircraft, I would be blamed, until one day the wings did fall of a model and I was blamed. That joke lost its appeal thereafter. The moral of this story is do not send a set in for repair with inappropriate nicads installed, without expecting to renew them. The only thing worse is to send a set in for repair without the batteries used on the fatal occasion, for the most probable cause of the problem was those batteries. In that situation, you will only end up with a "defect not confirmed" tag and a bill for checking the set. After re-installing the defective batteries, a second crash is the certain result. Yet over and over again, sets arrive for repair with inappropriate nicads or without battery packs. As stated previously, the battery is the heart of the R/C system and the well being of that system is in the hands of the operator. Furthermore, cutting corners on the cost of Rx nicads is -being very foolish indeed - a model travelling at lO0km/h can make a siza ble hole in somebody's head. Choosing batteries How then do we arrive at the choice of an appropriate battery pack? Most commercial R/C equipment comes complete with nicads and charger and thus presents no problem, as the manufacturer ensures 40 80 i---.. ~ _/ .,,,...-- ► ~ ... / 40 CAPACITY MEASURING CONDITIONS : CHARGE: 0.1C x 16Hrs. DISChARGE : 0.2C EV : 1V !f:! 0.5 ..__T5!P~~E. 0 0 ~ ~ ~ ~ 1~ No. OF CYCLES Fig.5: discharge capacity vs. number of cycles for a typical nicad cell. Under normal conditions, nicads are good for over 500 charge/discharge cycles. 84 SILICON CHIP 35 E w 50 ---_,,r./ / --- C 30 ~ ~ ... ~ V/2ftESSURE / 20 \ -~-- .- = .;-- =... CYCLE CONDITIONS : CHARGE: 0.lC x 11Hrs. DISCHARGE: 0.7C x 1Hr. w 5 VOLTAGE 60 C "' ~ - ~ w 25 .., 20 100 150 CHARGE INPUT (% OF CAPACITY) Fig.6: cell voltage, internal pressure and cell temperature as a function of charge input. Note how the cell voltage drops if charging continues after it is fully charged. Note also the increases in temperature and pressure as charging proceeds. Fig.7: the effects of temperature on cell voltage during charging. Nicad capacity is specified at 20°C and must be derated for higher temperatures. CHARGE : 150mA (C/J_j) x 5Hrs. - 1.6 / 1.3 v --l---- ~ / 1o•c 2o·c V 4s•c 1.2 0 2 CHARGE TIME (HOURS) that the correct cell type is fitted. The problem arises with sets sold for dry battery operation which have nicads fitted by the operator, and in sets in which the original cells have been replaced. In addition to this, the performance of the set on dry batteries or inappropriate nicads is very much influenced by the design of the Rx circuit. Such matters as decoupling, voltage stabilisation and low voltage operation all play an important part in this situation. Fig.1 illustrates the basic pros and cons of dry batteries versus nicads, when used in R/C systems. The very flat voltage curve and extremely low internal resistance of the nicad puts it clearly in front of the dry cell. In fact, it amazes me that dry cells give as satisfactory a result as they do and it speaks volumes for the quality of modern circuit design. However, they can cause excessive servo jitter as the cell ages. Fig.1 also shows one of the basic dangers in using nicads and that is the rapid voltage drop [beyond the "knee") at the end of the usable portion of the curve. Nicads pushed to their limit can collapse in the space of a 15-minute flight with very little warning. The moral here: land at the first sign of trouble and check range and battery voltage as well as for mechanical defects in the airframe. Modern nicads fall into broad catagories regarding design and construction and the Panasonic catalog lists the following types: Standard, Rapid Charge, High Temperature, High Capacity, High Rate Discharge and Rapid Charge, Super High Capacity and Rapid Charge, Memory Backup and Consumer Type. From this bewildering array, which cell do we choose? To begin, we must establish how . long we wish to operate between charges. A 500mA.h cell will quite safely provide 2 to 2.5 hours of operation on a 4-servo model aircraft. The same size cell will provide approx 4 hours operation on a standard Tx. This is usually considered adequate for most modelling applications. Next, we must establish what type of load 2.5 amps represents in relation to a 500mA.h cell. Obviously 2.5 amps drawn from a lead acid car battery is not a heavy load but does it constitute a rapid discharge from a 500mA.h cell'? This is not so easily settled and there is no definition of what constitutes a rapid discharge rate in any catalog that I could find. Fig.2 does give some clue in that 4C (4 times the cell capacity in milliamps, 4 x 500 = 2000mA or 2 amps) is beginning to stress the cell and efficiency has dropped to 90% of normal. Note also that the voltage available has fallen, despite the low internal resistance. Fig.3 shows the voltage curve for a consumer type cell at C/2, C and 2C. Thus, in the interests of efficiency, cell life and voltage available, it pays to use the largest capacity cell that the weight penalty will allow. Note that 2.5 amps from a 500mA.h cell is 5C while the same current from a 2.5A.h. cell is only lC. The airborne battery cells should be a high discharge type if the capacity is kept to a minimum. The AA cell is a borderline case and may be a high quality standard cell. One final word here on the effects of genuine interference: if you are using inappropriate, aged or otherwise defective cells, all of the servos will begin to chatter when interference is encountered. This gives rise to the condition described earlier, thus ensuring a crash, whereas cells in good condition may ride out the crisis. Finally, a brief word on charging: nicads are very simple to charge and under ordinary conditions will give well over 500 cycles in their lifetime. Fig.4 shows the effect of depth of discharge (D.O.D) on cell life. In this regard, there is an ever raging argument in R/C circles concerning the use of cycling chargers and whether to discharge every time before charging or not. My opinion is that it is worth doing. Why? Fig.5 shows the cycle life of nicads based upon the 100% D.O.D cycle. As can be seen, the minimum life is 500 cycles. Now this represents 10 years of charging every Saturday night with a full discharge before every charge and that is the minimum figure. Don't overcharge Overcharging can also damage nicad cells. One big problem faced by the model aircraft people in particular is the situation where a set is charged on Saturday night but the model is not flown the following day. Next Saturday, what to do? The set is still charged although self discharge will have reduced that charge by an amount unknown to the modeller because that rate depends on all sorts of things including cell age, internal condition, temperature and so on. Also, if the kids have access to the garage, they often show Dad's pride and joy to their mates and use half the charge in the process. Rarely is this communicated to Dad. The moral? Do yourself a favour. Discharge the cells immediately to their endpoint voltage (1. 1V per cell) and then charge them for the full 14 hours. Charge as close to the flying session as possible. Also, replace the cells every 5 years and check them every 6 months for corrosion. Replace any airborne cells involved in a heavy crash, particularly if physically damaged. High "G" forces can internally weaken a cell which can result in a later failure in flight. ~ SEPTEMBER1990 85 \R ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJA YCAR ELECTRONICS JAYCAR ELECTRONIC 1R ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONIC \R ELECTROt ' NI( .ECTRONICS .ECTRONICS .ECTRONICS .ECTRONICS .ECTRONICS .ECTRONICS .ECTRONICS I .ECTRONICS .ECTRONICS Jaycar has done it again. We have made a scoop purchase of distress stock petrol fume detectors at a never to be repeated price. Two models are available: .ECTRONICS uA-2A .ECTRONICS .ECTRONICS. This unit consists of cold sensor® detector (which is situated in the bilge) wiring loom and control unit/alarm. The .ECTRONICS. control unit sits in a gymbal type bracket. It has an on-off-test switch alarm buzzer and light Both light and buzzer go off .ECTRONICS. when fume concentration is still well below (20%) explosive level. The unit also includes a testing gas spray peak . .ECTRONICS: This non-toxic non flammable gas allows you to test the system safely. No more dangr.rous petrol soaked rags! ECTRONICS Draws 85 uA when operating so it is OK to virtually leave on indefinitely. Can be switched off when boat not in use. ECTRONICS. This unit sells in the USA for $!20 (US) but don't pay this much! Grab one now from Jaycar for only $39.95. That's rights 1/3 .ECTRONICS .ECTRONICS the US price. The local distributor sacrificed this stock to us so you would save! Now you have no excuse lo protect you. your .ECTRONICS family and expensive boat from the danger of a petrol explosion! .ECTRONICS. .ECTRONICS Cat.LA-5270 .ECTRONICS GvM-5o .ECTRONICS ECTRONICS This unit is permanently wired into your boat and does not contain a test switch. It's operation is automatic. ECTRONICS It consists of an attractive circular transducer, cold sensor® and testing gas. ECTRONICS ECTRONICS SellsintheUSAfor$70(US). ECTRONICS Cat LA-5272 ECTRONICS ECTRONICS Exclusive Cold sensor® Features ECTRONICS ECTRONICS - Detects gas instantly (no warm up) ECTRONICS - Does not bum vapour for detection (intrinsically safe) .ECTRONICS • Detects gas above the upper explosive limit as well ~g~~:g~ Longest sensor life of popular types. 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VOLT ' 1.i.' 51!1 ~ :::·,~~,=~=~·~J::;~:~~;c:oo,:;:;;.,, §!ii ~ ~if;is ~ ~•:mt ::: :~ ., .§~~:;~~;~;~' " 15 3075 :,~:l,;,_~:~:r,;,_::_:i,'l_:_ am':roblac" ig:g~:gi ':.:' <at>zmmmmmmmmmmm,mgmmmmmmmmmmms'* ~;~, ;~;, Iii rFL~~R~~NTT IN~~;g~~N §!ii I :5 .. earnao!"AMP .ECTRONICS i._-i,1._i,'1:,'1,_'i._,::::::,$::,:-:-.-.2·• 4.95 cacst,an LA. _ ii\ _ '·,,•',,;' . A '.:,_:·:. . __ • ,·::' .,:,'.,A:: __ _•,,._'·,_;,::'--:.• . -~•S<mm 9 st HM- ;;: ; ;; I :i,,':,,·:_i:',,,,i,i'_',,,,,,,,,•::,,,,:_::_.:: ~. ~OLH N D~::HT :.:.! I~~~~v~~~]:, I I/ I: :~:,:;: J b' \ Em :'i, .... . . . , , ,. . ..,. Bst$l04-1.10 Ill; $ 11 50 • ~ - ~ ·..;p i ,i,!,i,! ~,l ... ,. . _,, .J :>.:: I ELECTRON! ___ .. -· .... _ - . 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SPEAKERS 6"WOOFER $69 S"WOOFER 4/8 ohm 120W rms Cat. CW-2142 I;~mm 2' 3kg (6.61b) $99 10"WOOFER JAYCAR ELEC 4/8 ohm 180W rms Cat. CW-2143 $149 Hil~! ~~g:= 12"WOOFER 4/8 ohm 200W rms Cat. CW-2146 $179 JAYCAR ELEC Dome Midrange 4/8 ohm Cat. CM-2080 t $47■ 50 Dome Tweeter 4/8 ohm Cat. CT-2010 $29 ■ 50 :1_11 f i f ~t~~ ~i~]~ mI JAYCAR ELEC JAYCAR ELEC ~~g:= ~t~) JAYCAR ELEC :1: ~~~g~~ !t!l 1 } JAYCAR ELEC / ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE< ELE1 ELEI ELE1 ELE1 ELE1 ELE1 ELEI r ~~g:= ~t~: JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JA YCAR JAYCAR :::: JAYCAR JAYCAR }VIFA SPEAl(ER l(ITS - BACI( IN STOCI(! f 1 We all know how fantastic the VIFA SA-Series speaker units sound. It would not be an exaggeration to say that they generally perform as well as \ build equivalents that cost twice as much. :::: ':': VIFA SA-50 :Ill 1 1\1 ~:!!t~~t RMS full kit only $369 VIFA SA-70 2 way kit 50 watts RMS full kit only $449 ·································································· ········•········· ,.,;,.. -· .. . ____ .. ·-· ··---· .. __ •. ;JAYCAR ELECTRONICSJAYCAR :JAYCAR ELECTRONICSJAYCAR :JAYCAR ELECTRONICSJAYCAR ,JAYCAR ELECTRONICSJAYCAR ;JAYCAR ELECTRONICSJAYCAR ;JAYCAR ELECTRONICSJAYCAR '• 1• "" • □ c• ,--,Tn,-,, ""'' 1.,,,. •a VIFA SA-100 2 way kit 70 watts RMS full kit only $699 iiiiiii!iiii!iiilii!!ii!il!!i!!i!!li!iili!i!! ____ .. ·-· ··---· . . -· ... ____ . ·- · ··---· .. -· ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECT YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECffiONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR c1 c;cma•11c<> 11, YC • o_c;1 i:r.i:cot,.UC_C:. IA YCAR..£1..ECillOMCSJAYCAR ELECTRONICSJA YCAR VIFA SA-130 3 way kit 90 watts RMS full kit only $999 1 il1 r ::!: ~ij:~g:=m: !~U~lj j:~g:= ~t~: JAYCAR ELE, JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCARill . .:_._:_::,::..:<:::,:-::,:,::::::::,:.:.:-:.:.::::::::.:. CAR ELECTI .• . ··--·· .. -· ... ---- .. ·-· . . . CAR ELECTI ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRO NICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJA YCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTI ELECTRONICSJA YCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTI ~ef: EA April 1982 Cancel out the lead singer from your favourite record and by means of this kit substitute your own voice! Complete kit Cat KA-1430 $24.95 Ref: Silicon Chip June, July 1988 h quality, reasonably priced Hi Fi stereo preamp is presented here. Ideal for home or road work, it can be matched with any power amp with a standard input sensitivity of 1V rms. It is housed in a 44mm black rack case and requires 240 volts AC. See catalogue for full details. Cat KC-5033 $229 - h 0 - • *--a.-$1):1$l)•-- - :- - ·- :;;":: - ~~ -;;"f'' ' :;:..:: -.:.. 1/3 OCTAVE EQUALISER KIT Ref: Silicon Chip March 1989 Cat KC-5055 $239 -- ~:«,-:«,<,:.<,W',WN¼<WV;« =- ,. ,:: :~ ~))tDrJI1Fs~jj/~;;/LI . ef Silicon Chip September 1989 at. KC-5055 ORMALLY $349 HIS MONTH •·•••••· •• .•.• ,•,•, •,•,•.❖ ·,❖.•,•,•,•,•,•···········•:•.•,•,•·············· 1GHz DIGITAL FREQUENCY METER Ref: Silicon Chip NiN/Dec 1987 Cat KC-5013 $299 :~Jj~~:.~~~~:TH $8.95 ea % <at>, • 5JAYCAR ELEClRONICSJAYCAH tLtC IHONICSJAYCAH tLtC I HONICSJAYCAH t LtC I HONICSJAYCAH tLtC IHUNICSJAYCAH tLtC IHONICSJAYCAR ELECTRONICS ELECTRONICSJAYCAR ELECTRONICS SJAYCAR ELECTRONICSJAYCAR ELECTRO NICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS ELECTRONICSJAYCAR ELECTRONICS SJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS ELECTRONICSJAYCAR FI ECTRONICS S. I~ '::::~::::•.····· · ········•···•···· ··············· ··· ····· ······ ·· ··· ··········· · ··· · ··· ··· ····· ··· ··· ··· ··················· ·· ··· ·········· ··· ··· ··· ··· ····· ····· · ··· ··· · ··· · ··· ·· ··· ····· ··· · ····•.,.,,.,~:::;:::,::•:•··· ···· · · · · · · · ·· ·· .. · " "·· ·· " · · " ······ ··· ····· ···· ·· ····•:,::;:;:;:,i:::::••·❖:,:.:,:..,:. ••,.,•••••,••,.,•••,.,.,.,.,.,•••,.,.,.,.,.,.,.,,,,,,,,:::: ECTRONICS 1 t· Well~r WTCPS - Station ~ Cat. TS-1000 \:?' Waterproof Box Bargain ,,,, \'- ) ,., \, $ 149 ■ 50 -::::: ' I~~16°DRAWER .PART~ ~ \\ ~ -·~::c.--- INET 16 drawer cabinet to hold all of your :.:·.' bitsandpieces-resistors,capacitors, semis. drill bits, nuts & bolts, etc. :!i Drawers have a stopper that stops the m drawer from coming out completely and cataloguesfor$70. -~-◄ ~rON~.,LY. JAYCARELE ,. \ \. . ./,. ...........·...-.:: :.,:.,:........·.·········.....................•.•······...·..............,.: · .:: $ 12•95 ======Wl~ • Dual recording • Personal greeting • Call screening • Personal memo record • One touch playback • Digital message counter• Answer onty/message limit• Ring selector • Tape saver• \ { Automatic on • Fast forward and rewind • Easy to replace microcassette • Expanded message length • REMOTE CONTROL FEATURES• 13 function beeperless remote control• Remote on• Personal 3 digit security code • Fast forward/revvind • Greeting change • Greeting breakthrough • Save messages• Cancel messages• Toll saver• Last message indicator• Full tape retrieval• Repeat playback • Personal memo record. This answering machine has every feature that you will l?ller require in an answering machine. One year warranty. A quality product. 12.&vcr <at> 150mA ~~~g~= !~! JAYCAR ELE JAYCAR ELE ::: ~~;: o~:~~~Si1iJJ,;;~ j~~g~=~t~ JAYCAR ELE JAYCAR ELE JAY CAR ELE ~1~g1= ~t) ~;~~'.~~ts build in the probes $8.95 pr ~ e~~!; _! : ! ~ ~ ! !a~tyEre~ o~!a~r~ a~!~~m ~!~:w!!~~:~e~ o~ se. ll featu.res Digital Reco rdding whereby your voice is recorded on a microchip. 8pecIa I1eatures meIu e: JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE JAYC~R ELE JAYC R ELE JAYCAR ELE JAYCAR ELE JAYCAR ELE Are you sick and tired of those old multimeter leads braking all the time? Jaycar now stocks the same leads as supplied in our Metex ~ge of quality multimeters. Supplied with heavy duty cable Right angle banana plugs vvith plastic sleeve !;;:;,... f Cat. ZL-3820 $2 99 H"1gh Qua1·1ty Mult"1meter Leads ,:: supplied. Drawer size 1lO(L) x SO(W) x ) 34(D)mm. Total size 185(H) x 242(W) x ·''.'· 124(0)mm. Cat. H8-6320 :,: ,•:.:, JAYCAR ELE JAYCAR ELE JAYCAR ELE · . ··-; . ·. • ,:: spilling all over the place. Each drawer :j: AMP IC ~;, ·.·•.< ;1~~1 $29 95 m can be split into 3 with the dividers I ·\: !~~g~=~t~ 8 WATT AUDIO ' ;~~g~~t~ -:::r DA 2002 TheboxismadebyLumeinltaly. lt'swaterproof/hoseproof greyABSwithaclearhd .. Thehdactuallyhasarubber gaskettoensureawatert1ghtseal Size 150(L) x 1lO(W) x 70(H)mm. This type of box is in other JAYCAR EU JAYCAR EU ·· { i::: J ,;:; ? T MiNiATURE METALDESDLDER TOOL JJ~~g~ EELLEE JAYCAR EU JAYCAR EU JAYCAR ELI JAYCAR ELI JAYCAR ELI JAYCAR ELI ~ §~I~~t: Iif::::~,~:o !lu~g i~m i~:: I~~~~:~ff,;~:.i::: ~~!~: I~!~) If Lifetime Guarantee $&.S0/10 I ONLY $3.95 JAYCAR SOLDERING IRO~ Ideal for the hobbyist and handyman. Our lowest price 240 volt quality iron has a stainless steel barrel. 30 watt. Cat TS-1450 ..dllllllllllll= $16 • 95 Q 11), f PLASTIC VICE ::I i ALL1NEAR =-- ""-" "-"-"" j:~g:= l j:~g1= ~t: • pPLICATIONS <at> ""_"J 11111 3:~g1= ~~ JAYCAR ELI Over 1200 pages of fully indexed and cross referenced applications using both monolithic and hybrid circuits from National Semiconductor. Cat. 8N-4005 JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR $29.95 EL EL ELI ELI ELI EL .. .. . ,A: !~~g~= ~t JAYCAR EL JAYCAR EL JAYCAR EL • • ttf~~a~t~l~ f d Corcord 2137 $ 3.75 JAYCAR EL , Telephone (02) 747 2022 $ 4.5o ROAD FREIGHT ANYWHERE JAYCAR EL JAYCAR EL FACSIMILE (02) 744 0767 TOLLFREE (008) 022 888 $50$99.99 $ 6.50 IN AUSTRALIA lup 1020kg) ;; JAYCAR EL I ------------=========..::O:.::.VE:::.R:..::$:.:,:100:::__ __::::$8::;:.0::::0_ _ _.:_S1;:3·:::50:.__ _ JAYCAR EL ' , 188 Pacific HW'{ {Cnr. Bellevue Ave) (02) 439 4799JAYCAR EL GO RE HILL - Mon-fri 9- 5.30 Thurs 8.30- Sat 9 - 4pm JAYCAR EL 117 York St. (0212671614SYDNEY - CITY JAYCAR EL 144 Logan Rd (07) 393 0777 Mon-Fri 8.30 - 5.30 Thurs 8.30 pm - Sat 9 - 12 BU RANDA QLD ' JAYCAR EL Mon-Fri 9 - 5.30 Thurs 8.30 - Sat 9 - 12 355 .Church St (Cnr. Victoria Rd) (02) 683 '5377 PARRAMATTA JAYCAR EL Shop 2, 45 A'8eckell St City (03) 663 2030 MELBOURNE-CITY Mon-fri 9 - 5.30 Thurs 8.30 pm - Sat 9 - 4pm JAYCAR EL Mon-fri 9- 5.30 fri 8.30- Sat 9- 12 JAYCAR EL 115 Parramatta Rd (02) 745 3077 CONCO RD 887-889 Springvale Road Mulgrave (03) 547 1022 SPRI NGVALE VIC JAYCAR EL Mon-fri 8.30 - 5.30 - Sat 9.00 - 12 Nr Cnr. Dandenong Road Mon·Fri 9 - 5.30 fri 8.30- Sat 9- 2 JAYCAR EL 121 forest Rd (02) 570 7000HURSlVILLE 190 Wright Street {Cnr Selby Street) (08) 231 7355 JAYCAR EL ADELAIDE S.A. Mon-fri 9 - 5.30 Thurs 8.30 pm - Sat 9 - 4 JAYCAR EL Mon-fri 9 - 5.30 fri 8.30 - Sat 9- 12 ;AR ELECTF JAY .AH 1:Lt: H NICSJ YCAH t Lt C HUNI CA 1:L C I H NI ::;JAYCAH tLt(.; I HUNIC:;JA CAH tU: . I HUNl(.;SJA Y AH L I A I CAR ELECTf I JAYGAR ELECTRONICSJAYGAR ELECffiONICSJAYGAR ELECTRONIGSJAYCAR ELECTRONICSJAYCAR ELECTRONICS.JAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTf I JAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTF IAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTF IAYCAR ELECTRONICSJAYCAR ELECTRONIC&JAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONIC&JAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTF IA YCAR ELECTRONICSJAYCAR ELECTRONICSJA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR 'ELECTRONICSJAYCAR ELECTF 1 JA YCAR ELECTRONICSJAYCAR ELECTRONICS.JA YCAR ELECTRONICSJAYCAR ELECTRONICSJAYCAR ELECTRONICS.JA YCAR ELECTRONICSJAYCAR ELECTRONICS JAYCAR ELECTRONICSJAYCAR ELECTf MAIL ORD ERS POST & PACKING P.O.Box185 Concord2137 HOTLINE 02 7471888 $10-$24.99 FOR ORDERS ONLY $25 -$ 49 .99 i VISA I[ MAIL ORDER VIA '2f Interesting circuit Ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates. 2.4GHz prescaler for 1GHz frequency meter This prescaler circuit can be used to extend the range of the SILICON CHIP 1GHz Digital Frequency Meter to 2.4GHz. It is a divideby-256 circuit and uses a MAR-1 (or MAR-2) monolithic preamplifier, a Telefunken U864 prescaler (wired to divide by 4), and a Philips SAB6456 prescaler (wired to divide by 64). The divided output is taken from pin 7 of IC3 and drives emitter follower stage Ql. Since 2.4GHz divided by 256 gives 9.3MHz, the output from the prescaler can be fed via a miniature relay to the 10MHz counter based on IC6 of the DFM circuit. In practice, it's simply a matter of using the relay to switch the output of this prescaler with the output of the existing 1 GHz prescaler. Because the prescaler is a divideby-256 circuit, we need to modify the counter circuit to get the cor- +8Vo------, - - - - - - - - - - - - - - -.....- - - - - - - - - 0 + 5 V 0.1!. 220!l * Now that spring has arrived, this battery minder is just the shot for looking after any battery lying idle in that ride-on mower, boat, caravan vintage car etc. It's simple to make, costs less than $20, and can be clipped onto the battery and forgotten. 90 SILICON CHIP 01 BC547 OUTPUT 4701, * SEE TEXT rect readout. This was achieved by bypassing the divide-by-two stage in the counter and by altering the timebase ratio. To do this, (1) lift the wire link to pin 11 of IC4 and connect pins 14 & 15 of IC3 together; and (2), disconnect the lead to pin 4 of IC7 (4024) and connect it to pin 3 instead. You will also have to change the existing 1GHz prescaler to a divide-by-256 circuit by earthing pin 5 of the SAB6456 (IC1). Unless a signal is present, the prescaler will oscillate at its point of maximum sensitivity. This can be a problem as you can never be sure if the reading is a genuine count or due to oscillation. The circuit uses an LM317 regulator to set the output voltage. Low cost battery minder * The circuit uses a 30V centretapped transformer to drive rectifier diodes Dl and DZ . This then feeds an LM317 adjustable regulator which is short-circuit current limited to about 25mA by the 470 resistor. LED 1 in series with the positive output indicates when the battery is charging. Bill Jolly, Nambucca Heads, NSW. ($20) .,. To overcome this problem, start with the SAB6456. Lift the 470pF input capacitor and connect a 33k0 resistor between pins 2 & 8. This should provide enough bias to stop oscillation but install a lower value if necessary. Once you are happy with that stage, go on to the U864 and do the same thing from pin 4 to pin 1. There is enough room on the back of the counter to install a BNC input connector and a switch to control the relay. The 6V relay was mounted under the counter board near IC3 (10100) and run from the unregulated part of the supply via a dropping resistor. Do not forget to install a diode across the relay coil. The relay was also used to switch a LED on the front panel to indicate that the 2.4GHz prescaler was in use. Note that the 4700 output resistor shown dotted is actually on the main counter board (at pin 10 of IC3) and the emitters of the transistors (Ql in the prescaler & Q3 in the counter) are switched by the relay via short lengths of shielded cable. The sensitivity of the prescaler was 50mV at 2.3GHz and lOmV at 1296MHz. The circuit should be built on a double-sided PCB with an earth plane, using conventional RF techniques. This involves mounting the components on the track side and connecting the earth tracks to the ground plane using pinthroughs. Chris Skeer, Hatherleigh, SA. ($45) +12V 100k 100k .,. .,. .,.. .,.. ,. 1k .,. 3 0 2 1 7 3 4 2 10 4 1 5 5 6 9 8 6 7 IC2 4017 16 12k 11 9 RESET 15 LE06 DON'T WALK .,. + 100k .,. 47k .,. 22+ 1k S1 15k IC3 555 12k CLK 13 INH 024 4 IC1 555 07 BC547 ALL DIODES IN914 100k COUNT NUMBER 3 YELLOW for model railways You can use this traffic lights circuit to add realism to your model railway layout. It closely simulates the action of real traffic lights and even includes pedestrian crossing lights. Normally, the lights are green and the sequence is activated by pressing a pushbutton switch which simulates the action of a pedestrian crossing switch. ICl is a 555 timer wired in astable mode and this clocks a 4017 decade counter (IC2). This counts to 10 and then halts due to the clock 4 6 7 8 X GREEN Traffie lights .,. .,. 9 X Table 1: here's how the LEDs are cycled with each clock pulse. The sequence is activated by pressing a pushbutton switch (S1 on the circuit diagram). X RED X DON'T WALK X X t BlJTTON PRESSED HERE X X X X X X WALK WAIT X X X X X X X X X X = ON inhibit (pin 13) being pulled high on the lath count. ICZ's outputs drive 10 sets of OR gates made up of diodes Dl-D23. These OR gates drive transistors Ql-Q6 which in turn control the traffic light LEDs, and the "Wait" and "Don't Walk" LEDs. BUTTON PRESSED HERE Decoded outputs 6 & 7 of IC2 also drive transistor Q7. Thus, Q7 turns on 555 oscillator IC3 for two cycles of IC2 and this flashes the "Don't Walk" LED. At the end of the sequence, output 9 is high and so the green traffic light LED and the continued next page SEPTEMBER1990 91 CIRCUIT NOTEBOOK - CTD "Don't Walk" LED are lit. A new sequence is started by pressing S1 which pulls the reset pin (15) of IC2 high. Table 1 shows how the LEDs are cycled. Robert Parnell, Blacktown, NSW. ($50) ,----...-------'-="'-'~~W.,,r--.....---..------<p-----7r--~~~l~l~~A SWITCH 330!l IC1 MC3334P Electronic control for radiator fan This circuit controls an electric radiator fan by monitoring the engine temperMure via the factory fitted temperature sender located near the water thermostat. This sender usually activates a simple temperature warning light or a temperature guage. The circuit works by monitoring the voltage at the sensor and comparing it with a reference. It then switches on a transistor to activate the fan motor when the temperature reaches a predetermined point. The engine sensor voltage is applied to the wiper of VR1 which allows adjustment of the attenuation and DC offset. Diodes D1-D4 provide a reference voltage of about 2.5V and this voltage is applied to the top of VRL The signal from the wiper of VR1 is filtered using a 1001,tF bipolar capacitor. This is done to prevent false triggering due to short term fluctuations from the temperature sender. IC1 is a Motorola MC3334P ignition IC as used in several SILICON CHIP car ignition projects. The IC is used here as a comparator and transistor driver. This device has several advantages over other ICs: first, it can operate from - 40°C to + 125°C; and second, it can survive the harsh voltage transients from the automotive 12V supply. Pin 5 of IC1 is the comparator in- put. The output at pin 7 is open circuit when the pin 5 voltage is above 1.BV and low when the pin 5 voltage is below this voltage. The pin 7 output drives transistor Q2 which in turn drives Darlington transistor Q2 to switch on the fan motor. Alternatively, a relay could be 'c onnected between pin 7 and the + 12V supply and the transistors deleted. A 1N4002 diode should be connected across the relay coil to prevent back EMF damaging the internal transistor at pin 7 of IC1. VR1 should be adjusted so that the fan switches on at the desired temperature. John Clarke, SILICON CHIP. +5V TP1 1Hz 16 10 14 2 IC3 555 IC1 MM5369 2 ov~ .,. 1Hz timebase with variable pulse width Looking for an accurate 1Hz reference with a presettable pulse width? This simple circuit uses an MM5369EST timbebase (IC1), a 4518 dual BCD counter (IC2), and a 555 timer (IC3). IC1 divides the signal from a 3.58MHz crystal oscillator to give a 100Hz signal at its pin 1 output. Actually, there are two 92 SILICON CHIP IC2 4518 100Hz 15 8 7 1 ... other versions of this IC: the 5369EYR provides a 50Hz output, while the 5369AA provides a 60Hz output. Be sure to use the 5369EST to get 100Hz. This 100Hz signal is used to clock dual counter stage IC2 which divides by 100. The output is derived from Qi and Q4 of the second counter. These are dioded ANDed together to provide a negative-going pulse when counter 2 recycles. This pulse is used to trigger 555 timer IC3 which is configured as a oneshot. Its output pulse at pin 3 can be varied in width from 11,ts to 240ms by adjusting the 50k0 trimpot. Note that it is possible to obtain a higher voltage swing from IC3 by feeding it from a separate supply. In that case, the supply line should be cut at "X". R. J. Hose, Shepparton, Vic. ($25) COMPUTER BITS By JENNIFER BONNITCHA What to do when your computer goes bung; Pt.5 Why are motherboards called "motherboards"? It is because they have all those sockets into which "daughter boards" are plugged in, much like baby pigs suckling from the sow. But motherboards don't always lavish care and sustenance; they can be a source of trouble too. Since the motherboard is a large fibreglass sheet with connectors for the various plug-in cards, it is subject to stress and strain. As you add more cards, it tends to twist and flex, particularly in the less-well manufactured clones. On some cheap motherboards, inserting cards roughly can cause it to crack. That is the beginning of the end since the split becomes progressively worse until finally it breaks. Less obvious to detect is a nonfunctioning motherboard. Since nothing works, how can you eliminate suspect devices? If you think the motherboard could be at fault, check the following: • the power is actually switched on; • the power point works anyway; • all connectors are OK; • loose screws, etc on the motherboard, which could cause short circuiting; • correct system board settings as appropriate. After all that, you may need to call on your friendly technician for further help. Obviously, the amount of time you spend tinkering depends on your own capabilities. You should find the following voltages at the motherboard power connector [top left hand corner of photo): VOLTAGE PINS +4 .8 to 5 .2 +4.5 to 5.4 + 1 1.5 to 12.6 +10 .8 to 12 .9 P8-5 ; P9-3; P9-1; P8-4; P9-4 P8-6 P8-3 P9-2 What time is it? The internal rechargeable battery maintains the computer's real time clock. Just like the watch on your wrist, when the battery runs flat, the date and time are out. Replace the battery and all should be well. Occasionally, you may need to run your computer's diagnostic or setup procedure, even after using the DOS commands DATE and TIME. Typically, this will reset the real time, rather than the system time and so will remain in effect even when the computer is turned off. Common programs include TIMER, SETDATE, SETTIME and so on. Check your DOS manual for further information. A window to the world Monitors and video cards were discussed at some length in earlier articles but what do you do when they play up? There are a few things you can do to check the operation of your monitor: • Is the monitor actually turned on? Don't assume that since it usually comes on when the computer does, that it is broken in some way. Users not familiar with your computer's operation may have assumed that the monitor needs to be turned off separately to the system unit. Check. • For those monitors with integrated power cables, check tha.t the cable is securely attached to both the monitor and system unit. If it is, and the monitor power switch is on, try using a separate power cable, since there could be a problem with the outlet from the system unit. • Check the brightness and contrast controls if nothing appears on the screen. Someone may have turned them right down and forgotten about them, so that the monitor appears dead. Again, different users may have adjusted them to suit a particular program and the settings may be inappropriate for the program you wish to run. • Check that the monitor cable is securely attached to the system unit. Several cards can have lookalike sockets. Check that the monitor is connected correctly. • If possible, check the suspect monitor on another computer and a different monitor on your computer. The key to success is elimination. • If the monitor comes on but the program you want to run seems to do nothing, check the installation procedure. You need to make sure the program knows exactly what SEPTEMBER1990 93 Table 1: System Board Errors Table 4: Hard Disc Drives 101 1 02 1 03 1 04 1 05 Problems with the hard disc return the 1 7xx series of codes: System Board Error; Interrupt failure System Board Error; Timer failure System Board Error; Timer interrupt failure System Board Error; Protected mode failure System Board Error; Last 8042 command not accepted 1 06 System Board Error; Converting logic test 1 07 System Board Error; Hot Non Maskable Interrupt test 1 08 System Board Error; Memory select error 1 09 System Board Error; Memory select error 1 21 Unexpected hardware interrupts occurred 161 System Options Not Set - (Run SETUP); Dead battery 162 System Options Not Set - (Run SETUP); CMOS checksum/configuration error 163 Time & Date Not Set - (Run SETUP); Clock not updating 164 Memory Size Error - (Run SETUP); CMOS setting does not match memory Table 2: Keyboard Errors 301 Keyboard did not respond to software reset or a stuck key failure was detected. For stuck keys the key scan code displays in hexadecimal. 302 System Unit Keylock is locked 303 Keyboard or System Unit Error 304 Keyboard or. System Unit Error; Keyboard clock high The most likely reason for the code 301 to be on the screen during the POST routine is that your keyboard connector plug has worked its way out of the socket. Push it in and everything should be OK although it may be necessary to re-boot. Table 3: Video Adapator Follow your nose and try the switch settings, audio response etc. Video adapters can return 4xx, 5xx, 24xx and 39xx codes: 4xx Monochrome Display Adapter (MDA) errors 401 Monochrome memory test, horizontal sync frequency test, or video test failure 408 User indicated display attributes failure 416 User indicated character set failure 424 User indicated 80 x 25 mode failure 432 Parallel port test failure; monochrome display adapter 5xx Colour Graphics Adapter (CGA) errors 501 CGA memory test, horizontal sync frequency test, or video test failure 508 User indicated display attributes failure 51 6 User indicated character set failure 524 User indicated 80 x 25 mode failure 532 User indicated 40 x 25 mode failure 540 Oser indicated 320 x 200 graphics mode failure 548 User indicated 640 x 200 graphics mode failure 24xx Enhanced Graphics Adapter (EGA) errors 39xx Professional graphics controller errors 94 SILICON CHIP 1701 1702 1703 1704 1780 1 7 81 1 7 82 1 790 1791 Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed disk disk disk disk disk disk disk disk disk POST error adapter error drive error adapter or drive error O failure 1 failure controller error O error 1 error Table 5: Floppy Disc Drives If the drive receives power separately from the computer (ie, it is an external drive), check that it is plugged into the power outlet and is turned on. Check the drive is configured correctly and for correct rotational speed. Check the voltages at the, power connector. Pin 4 should be at +5V (±0.2V) with respect to pin 2 while pin 1 sould be at + 1 2V (±0.6V) with respect to pin 3. 6xx Floppy drive/adapter errors 601 Floppy drive/adapter Power On Self Test Failure 602 Drive test failure; disk boot record is not valid 606 Disk change line function failure; drive error 607 Disk is write protected; drive error 608 Bad command; drive error 61 O Disk initialisation failure; track O bad 611 Time-out; drive error 61 2 Bad Controller chip 613 Bad Direct Memory Access; drive error 614 Bad Direct Memory Access; boundary overrun 61 5 Bad index timing; drive error 61 6 Drive speed error 621 Bad seek; drive error 622 Bad Cyclic Redundancy Check; drive error 623 Record not found; drive error 624 Bad address mark; drive error 625 Bad Controller chip; seek error 626 Disk data c6mpare error 73xx 3.5" external diskette drive errors 7306 Disk change line function failure; drive error 7307 Disk is write protected; drive error 7308 Bad command; drive error 731 O Disk initialisation failure; track O bad 7 311 Time-out; drive error 7 31 2 Bad Controller chip 7313 Bad Direct Memory Access; .drive error 7314 Bad Direct Memory Access; boundary overrun 7315 Bad index timing; drive error 7 31 6 Drive speed error 7 321 Bad seek; drive error 7322 Bad Cyclic Redundancy Check; drive error 7323 Record not found; drive error 7324 Bad address mark; drive error 7325 Bad Controller chip; seek error 7326 Disk data compare error Problems with your motherboard are not nice but it pays to check the obvious before calling in a technician. In particular, check that all external components (keyboard, monitor, disc drives, power supply & adapter cards) are plugged in and working correctly. kind of monitor and graphics board you are using. The same goes for the video adapter. If you think you may have a problem with the video board verify the switch settings on th~ motherboard and video card. Turn on the power and listen for the audio response produced by the POST (Power On Self Test). Most computer manufacturers use one beep to indicate success and two beeps for failure - although you should familiarise yourself with your own computer's POST characteristics. Try running the diagnostics to test the adapter. Note that adapters which are · not supported by the diagnostics will generally fail the tests even though they may in fact be good. But it wasn't working when I called you ... Intermittent problems are the most difficult to deal with and often there is only a report from a worried user who cannot describe the problem accurately. Interpreting a user's description then guessing why the problem occurred inevitably leads to frustration on all sides. Try getting the user to write down exactly what happened and, as far as possible, what was done in response. Try to re-create the problem yourself. Once you see the problem, try running appropriate diagnostic software. Most of the reputable manufacturers supply good to very good advanced diagnostics software with their computers. It is not there just because the programmer liked to test out the colour palette. Many diagnostics routines can be set to run many times over, thus continually testing the suspect equipment. Try alternately heating and cooling. Heat from a hair dryer can help find a problem, though do be very careful not to overdo it and cause damage to other components. Experience [sometimes bitter), practice and good old commonsense will tell you when enough is enough. Cooling can often have the opposite effect. Sometimes spraying the suspect component with a freezer spray will help isolate heatrelated failures . The time of day can also create problems due to the routine nature of machine operation, airconditioning temperature, humidity, and power requirements (both from within the building and from other buildings drawing power from the same line). Check the location of power and telephone cables in relation to your computer and so on. External influences can have a quite significant effect on your computer system. For those willing to proceed further with troubleshooting, rather than call in the cavalry [read: service technician), the following are some voltage measurements for various components, together with some [though by no means all) of the more common system messages gleaned from IBM technical and maintenance manuals. Naturally, you should consult your own manufacturer's manuals for information specific to your computer. Power supply The power supply voltage between pins 1 and 5 [ground) should be 4.5 to.. 5.4 volts DC on the system board connectors. If not within this range, the power supply is bad. Remember that if you want to test the power supply, it must be installed in the system and the system must be running. This is because it is a "switching" power supply and thus must always have a proper load to function correctly. If you take the power supply out of the system unit and plug it in, it will not operate. You need to have it plugged into the motherboard and attached to at least one disc drive. Keyboard troubles Keyboards typically return a 3xx error code. If you get one, turn off the computer, disconnect the keyboard and check the following voltages at the system board keyboard connector: Getting zapped Beware of static electricity and other external environmental influences. Static in particular can cause what appears to be an intermittent problem. Does the filing cabinet regularly "zap" you when you pass? Synthetic carpets can be a real problem in this regard. PIN 1 2 3 4 5 VOLTAGE +2 .0 to +5.5 +4.8 to +5 .5 +2 .0 to +5 .5 GROUND +2.0 to +5 .5 SEPTEMBER 1990 95 C11915...... $325 EXPANDED DYNAMIC RAM RANGE" REMOVABLE CARTRIDGE HARD DISK ~ TOWER COMPUTER CASES ............... $2411 POWER SUPPLY TO SUIT(220W)....... $2215 4164-10 4464-10 4464-08 41256- 10 41256- 08 44256-10 44256- 08 1M-10 1M-08 (64K X 1) (4 X 64K) (4 X 64K) (256K X 1) (256K X 1) (256K X 4) (256K X 4) (1M X 1) (1M X 1). 1-9 $4.95 $5.50 $5.95 $4.50 $4.95 $12.95 $13.95 $12.95 $13.95 10+ $4.50 $4.95 $5.50 $3.9"5 $4.50 $11.95 $12.95 $11.95 $12.95 Ricoh R260 20 M/Byte Removable Hard Disk Is a subsystem for AT or 386 systems. Extra 20 M/Byte cartridges are available. To i,nable the end user to build a library that can be safely locked away. Or taken to another site that Is using the same sub-system. It's the ultimate in hard disk back up systems or for transport ablllty of data. Includes a cartridge X20022 ............••.... $1, 195 Extra 5 1/4" 20 M/Byte cartridge for disk (Ricoh RH5260) X20024 ..........•.•........$220 • IBM' compatible, 28 msac access, 3 month warranty Without controller. $795 80 M/BYTE VOICE COIL HARD DISK • IBM' compatible, 25 msec access, 3 month warranty Without controller.$1.495 330 M/BVTE VOICE COIL HARD DISK • IBM' compatible, 18 msec access, ESDI, 3 month warran·ty Without controller.$2,995 ROD IRVING' SUPER VGA 40M PACKAGE! 40MEG 40 MEG AT • 16 MHZ LANDMARK • MINI CASE & P.S •1MRAM •G7CARD • 101 KEYBOARD • IDE/ FDC CARD • 40M HO/ 28MS • 12 MB • 1.2M FFD $1,395 AT • 16 MHZ LANDMARK • MINI CASE & P.S •1.2MFDD •1MRAM • 101 KEYBOARD . • IDE/FDC CARD • 12M MB • EGA CARD • 40M HD/ 28MS monitor extra • 16 MHZ LANDMARK • MINI CASE &P.S • 1 M RAM •40MHD/28MS •12MMB • 101 KEYBOARD • IDE/ FDC CARD • VGA 256K CARD • 1.2 FDD $1,445 monitor extra $1,545 I I I• I• I' 80286-12 MOTHERBOARD (Extremly reliable Japanese Suntec Technology) ....-• • • 16 MHZ LANDMARK SPEED TEST EXPANDABLE TO 8 MEG OF RAM ON BOARD A 'EMSLIM4.00SUPPORTED • h (EasentlalforDeaktopPubliahlng) PQ~ FREE DOS 4.01 • 2 MEG RAM ,,., • SERIAL, PARELL AND GAMES PORTS. ~ *1.2M FDD 5 1/4" JAPANESE DRIVE &. • HIGH QUALITY 101 KEY KEYBOARD ~~ # _. 41.,J., I I -- ....,,~ a. 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The Mlcrollne 172 Is Ideal for the small business or home office being compact, reliable and having the speed to meet your needs. And you won't find It cheaper than at Rod Irving Electronics. By GARRY CHATT, VK2YBX Build this simple converter and listen to the 2-metre band on a shortwave radio Here's a ·VHF converter that's really easy to build. By combining it with a standard shortwave receiver, you can monitor activity on the 2-metre band. Most converter designs comprise an RF amplifier, oscillator and multiplier stages where necessary, and a mixer. The theory of operation is as follows: by amplifying the incoming VHF signal, and then mixing it with a fixed frequency (normally a crystal oscillator), the following outputs will be produced: fc + fO and fc - f0 where fc is the carrier input signal frequency and f0 is the local oscillator frequency. If we use 146MHz as the desired input signal and 128MHz as our local oscillator, the resultant output frequencies will be 2 74MHz and 18MHz. The latter is a very convenient output frequency as it allows a shortwave receiver is to be used as the "tunable IF" stage. We deliberately chose 128MHz as the local oscillator frequency so that the "image" (ie, the local oscillator frequency minus the IF) fell outside the commercial FM broadcasting band. If this had not been done, high power FM signals would interfere strongly with the operation of this converter. By carefully selecting the local oscillator frequency, we are able to eliminate additional stages of filtering from the converter front end. As it stands, the range of "images" is from 109MHz to 112MHz, a band where no high power signals should appear. Most shortwave receivers these days are equipped for SSB and FM reception. These are the two most popular modes of operation on VHF, so this converter can be quite useful for monitoring the local repeater, or for listening to some of the more exotic SSB signals. In addition, this converter can also be ANTENNA LOCAL OSCILLATOR SBL-1 MIXER 18MHz - - - O UTPUT Block diagram The design presented here is a good compromise between complexity and performance. Fig.1 shows a block diagram of the converter. We settled on a GaAsFet front end (Ql} to amplify the incoming signal. This stage is similar to the GaaAsFet preamplifier design published in August last year. The local oscillator stage is based on FET Q2 (configured as a Clapp oscillator) and this drives a buffer stage based on FET Q3. This configuration has been used before in VHF weather fax receivers by John Day, VK3ZJF. It provides OdBm output which is just sufficient to drive the mixer, an SBL-1 hot carrier dou- : 1 ~ 01 GaAsFET 146MHz PRE AMPLIFIER used to listen to the geostationary and polar orbiting weather satellites. This is easily done by realigning the converter to the 13 7MHz band and tuning the receiver to 9MHz or so. Note that the IF output of the converter is broadbanded, so that the exact frequency received is determined by tuning the shortwave radio (or antenna tuner) used. II II II II '"' II ------+----' 02 FET 128MHz OSCILLATOR 03 FET BUFFER Fig.1: block diagram of the converter. The incoming signal is amplified using Ql and mixed with the output of a 128MHz local oscillator. 98 SILICON CHIP IF OUTPUT IN;~T~ Fig.2: internal wiring of the SBL-1 double-balanced mixer module. 100 + .,. 16VWr 100k 18MHz SBL-1 -- -MIXER ~3,4 ... ANTENNA ~ .r 2 5 6 7 .001 'J:' ~-,,PUT 8 VC1 2-20pF 33k 22 2-20pF VC3 t ,. 16VWr 03 2N4859 .001J .001 10pF +10.6V .,. + 100!l G I L4 ~~~q 10pF 10pFj 100k """! ' J"" .,. 10pF+ .,. BLUE PIN G14=D s VIEWED FROM ABOVE VIEWED FROM BELOW 144MHz CONVERTER Fig.3: Q2 & X1 form a crystal oscillator whose output is buffered by source follower Q3 and mixed with the amplified signal from Qt. The broadband output from the mixer is then tuned using a shortwave receiver. ble balanced mixer module. Actually, best performance is obtained when an injection level of ± 4dBm is used but this would have involved adding another stage to the converter. Our choice of the SBL-1 mixer module was made to overcome the problems commonly encountered with active mixers; eg, noise, desensitisation, and insufficient local oscillator isolation between input and output ports. The advantages of using the SBL-1 are simplicity, outstanding strong signal performance, and high port isolation. Fig.2 shows the internal wiring of the SBL-1 mixer module. This particular model can be used at frequencies up to 500MHz. It is a passive device and hence has a 6dB insertion loss, but the preamplifier stage gain (Ql in Fig.3) has been set to overcome this and to provide some usable conversion gain. Circuit details Fig.3 shows the complete circuit diagram for our converter. As can be seen, Ql is a 3SK121 GaAsFet and is biased via a 100kn/33k0 divider network for about l0dB of gain. The output of this preamplifier stage is fed via a tuned circuit (VC2, 12, .001µ,F) to the 50-ohm input port of the mixer module. Q2 and Q3 respectively form the crystal oscillator and buffer stages. Crystal Xl is a seventh overtone crystal, so that the output of the oscillator is 128MHz. VC3, L3 and the associated .001µ,F capacitor form the tuned drain load for Q2. Note that the oscillator uses a U310 FET which is a rather special transistor commonly used in television tuners. FET Q2 is wired as a source follower to buffer the oscillator signal prior to injection into the mixer. The output from the buffer appears at Q2's source (S) and is fed to the low impedance LO (local oscillator) port of the mixer module via a low-pass filter stage consisting of L4 and two 10pF capacitors. To ensure stability, the preamplifier stage is run from a zenered 5.6 volt supply, while the crystal oscillator is operated from a 12 volt supply derived from a 3-terminal regulator (7812). This arrangement ensures that no damage can occur if the unit is inadvertently connected to a higher voltage. Construction The entire circuit is built on a double-sided circuit board, the top of which forms a groundplane to enSEPTEMBER 1990 99 Fig.3: the PC board should be assembled and tested one stage at a time as described in the text. When installing the parts, solder the leads on both sides of the board if the groundplane comes right up to the edge of the hole. !jlUT NO N 1001) ~ · sure stability. Fig.4 shows the wiring diagram. The main point to remember is that any component lead that goes to earth must be soldered on both sides of the board. In practice, this involves soldering the lead to the groundplane if the copper pattern comes right up to the edge of the hole. If the copper has been etched away from around the hole, no connection is made to the groundplane. Take care when soldering to the groundplane side of the board to enKeep all component leads short when installing the parts on the PCB and take care with the orientation of the SBL-1 mixer module. The blue pin is pin 1. 100 SILICON CHIP . ,O 'I !I r- · uf RFC1 sure that the component is not damaged. Use a soldering iron with a conical tip for best results. The most difficult components to mount were the lOOµF electrolytic capacitor and the small Murata trimmers which have only a very small lead area exposed on the top side of the board. This lead must be soldered to the groundplane. If difficulty is encountered soldering the trimmer leads, they can be bent outwards at right angles and soldered directly to the top of the board, without passing through the board. Construction requires no special techniques, although all component leads must be kept as short as possible. This is why most components are mounted horizontally Q on the PCB. The two shields ensure good isolation between the local oscillator and the RF input and should be mounted last. Note that these shields can be made from PCB material, or copper or bronze foil, then soldered directly to the top of the board. Winding the coils We deliberately designed the circuit so that constructors could wind their own coils (Ll-14), rather than relying on hard to get pre-wound types. Fortunately, there is a very easy way to wind the coils and that is to use a threaded 5mm-diameter bolt (obtainable from most hardware stores) as the former. It is quite an easy task to wind the wire PARTS LIST TABLE 1: COIL W INDING DET AILS L 1: 9T 25B&S tinned copper wire on 5mm thread, tapped 2.5T from cold end. L2: 6.5T 25B&S tinned copper wire on 5mm thread, tapped 2T from hot end. L3: 3T 25B&S tinned copper wire on 5mm thread. L4: 7T 25B&S tinned copper wire on 5mm thread. RFC1: 2T 25B&S enamelled copper wire on F29 ferrite bead . 2 2 1 1 2 PC board with groundplane, code SC 06109901, 168 x 70mm BNC sockets 50 x 5mm double-sided PC strips, or copper or bronze foil (for metal shields) SBL-1 double balanced mixer module 128MHz 7th overtone crystal, Hy-O code GE03S F29 ferrite beads (DSE Cat. L-1433) Semiconductors 1 3SK121 GaAsFet (01) 1 U310 FET (02) 1 2N4859 FET (03) 1 7 81 2 3-terminal regulator 1 5 .6V 400mW zener diode (ZD1) Capacitors 1 100µF 1 6VW electrolytic 2 22µF 16VW tantalum 10 .001 µF ceramic 1 27pF ceramic 4 1 0pF ceramic 3 2-20pF trimmers Resistors (0.25W, 5%) 2 100kD 1 1 800 1 33kD 2 1000 3 2700 Although not shown on the overlay, metal shields should be installed between the preamplifier, mixer and oscillator stages. These can be made from blank PCB material. into the thread of the bolt (see photo) and the pitch of one turn per millimetre is ideal. Table 1 shows the winding details for each of the coils. After winding the correct number of turns onto the bolt, cut the start and finish leads to a manageable length (about 10mm), then slowly wind the entire coil off the "former" by rotating the bolt. Mounting the parts We built the converter one stage at a time, to ensure that there were no errors. Start with the GaAsFet preamplifier stage (Ql}. After construction, it can be checked for correct operation using a known VHF signal and a scanning receiver, or by connecting the output at the .OOlµF capacitor via a CRO probe A 5mm-diameter bolt makes a very convenient former for winding the four coils (L1-L4) - see Table 1. to the input of a frequency counter. Normally there is some RF radiation in a typical amateur "shack" and the counter should show increased sensitivity. The next stage to build is the oscillator (Q2}. The output of this Where To Get The Parts The 3SK 1 21 GaAsFet is available from Dick Smith Electronics (Cat. Z-1845), the SBL-1 mixer and U31 0 FET from Stewart Electronic Components (phone 03 543 3733), and the 2N4859 FET from RS Components (stock number 649 021; phone 02 669 3666 or 03 330 3666). The 128MHz seventh overtone crystal is available from Hy-O Crystals (phone 03 783 9611 ), while the stage can be checked on a frequency counter or a shortwave receiver. The adjustment of the trimmer (VC3} is critical but by monitoring the DC current drawn by the stage, it's quite easy to determine when the oscillator is operating. Once the oscillator is running, the double balanced mixer and the buffer stage can be wired and the shields installed. SEPTEMBER1990 101 SC06109901 0 0 00 cO 0 Here are the actual size patterns for the double-sided PC board. Alignment Once the unit is built, alignment is easy. First check that the total current drain is in the order of 40mA or so. Next check that the DC voltages shown on the circuit are correct. There are only three adjustments to be made: VCl, VCZ and VC3. First, adjust VC3 so that the oscillator is running at the correct frequency. This can be done by connecting a frequency counter to pin 8 of the SBL-1. Alternatively, adjust VC3 until the input frequency can be heard on the correct IF. To do this, select your local repeater or beacon and 102 SILICON CHIP subtract 128MHz from the repeater output frequency to give the desired IF to which the shortwave receiver should be tuned. For example, a 146MHz input gives an IF of 18MHz, while 146.725MHz gives 18.725MHz, etc. Having aligned the converter to the correct frequency, peak both VCl and VCZ for maximum sensitivity or maximum quieting. Use the receiver's S-meter if one is available. A good time to align the converter if repeater use is spasmodic is during one of the WIA broadcasts which are normally transmitted on Sunday mornings . Transmission times vary from state to state, but many repeaters are used to re-transmit these broadcasts and transmission duration is about one hour. Our prototype performed remarkably well, giving good reception of all Sydney 2-metre repeaters plus many operating along the northern and southern coasts. Measured sensitivity was 0.2µ,V for 1 ZdB SINAD when using the converter with an FRG-7700. The unit showed a conversion gain of 3dB. Finally, the unit can be mounted in a metal box for best results. If you do this, use shielded RF cable between the board and the BNC input and output connectors. ~ PRICES ON RELATIVES LIKE YOU HAD A PERIPHERAL IN THE BUSINESS ATTENTIONIIII PS/2 OWNERS MODEMS 12 MONTH WARRANTY ON ALL DRIVES. $449.00 NEW 4Mb 3.5" Suits both PC and AT type computers-Auto sense can be configured in either 521 k, 2Mb or 8Mb increments up to four boards (128Mb) per system. Conventional/Extended/Expanded memory system compatible software supplied for setup and print spooler and RAM disk provision for external power supply to retain data after computer is powered down. We now carry the full range of the quality B.I.T. Modems at extremely competitive prices. These modems are Australian designed and supported and all are Telecom Approved. Performance and features are far ahead of the competition. Until now PS/2 owners wishing to transfer data to or from 5.25" diskettes only had the choice of using 360k. Now, with the ROCTEC RF572BS drive from PC MARKETPLACE, this has changed. The drive reads and writes both 360k and 1.2Mb disks. They come with software to support the 1.2Mb function not normally used buy the PS/2. All ROCTEC DRIVES use quality Japanese drive mechanisms and feature an extremely high quality finish. NEW32Mb RAM CARD NEW BIT BLITZER MODEL RRP $ 124E 1234E 449 499 OUR SELL SAVE $ $ 399 449 $299.00 50 50 r FLOPPY DISK DRIVE Formatted maximum capacity of 2.88Mb, supports 720k, 1.44Mb and 2.88Mb formats. Diskettes available. Bare Drive $225.00 5.25" Mounting Frame $25 .00 COMPUTER PART# SIZE AMIGA AMIGA AMIGA 02930 02932 02938 3.5" 5.25" 3.5" AMSTRAD AMSTRAD AMSTRAD AMSTRAD 02904 NEW NEW NEW 3.5" 5,25" 5.25" 5.25" ATARI ATARI IBM IBM IBM IBM IBM PSII IBM PSII 02916 D2918 D2946 D2948 D2950 02952 NEW NEW VARIOUS VARIOUS LAPTOP LAPTOP Phi{ (j{eeson 's PHONE (02) 418 6711 FAX (02)4186713 Mail Order Address: P.O. Box 1100 Lane Cove NSW2066 NEW 2.88Mb FLOPPY DISK CONTROLLER ~ We also carry a HUGE range of cables to suit IBM, Laptops, Macintosh and \.. Apple PC's. ~ Write or phone today for your FREE copy of our Catalogue! Supports all drive types 3.5' and 5.25'; 360k, 720k, 1.2Mb, 1.44Mb and 2.88Mb. Supports four drives of any format mix. Either 4 drives internal or 2 internal and 2 external. $199.00 Over 100 products shown with full details and specifications! CAPACITY COMMENTS PRICE 880K 3601880K 880K 720K 360K 1.2MB 1.2MB WITH ON/OFF SWITCH WITH ON/OFF SWITCH INTERNAL KIT FOR A2000 3.5" 5.25" 3.5" 3.5" 5.25" 5.25" 5.25" 5.25" 720K 360/720K WITH POWER SUPPLY SWITCHABLE, WITH POWER SUPPLY 269.00 299.00 720K 1.4MB 360K 1.2MB 360K 1.2MB WITH WITH WITH WITH WITH WITH 299.00 329.00 299.00 329.00 349.00 399.00 5.25" 5.25" 360K 1.2MB SUIT TOSHIBA, COMPAQ, ZENITH SUIT TOSHIBA, COMPAQ, ZENITH FOR FOR FOR FOR 249.00 299.00 229.00 269.00 329.00 329.00 399.00 PC1512/1640 MODEL PC 2000 SERIES MODEL PC 2000 SERIES MODEL LAPTOP SERIES ADAPTER ADAPTER ADAPTER ADAPTER ADAPTER ADAPTER PERSONAL COMPUTER MARKETPLACE FREIGHT CHARGES Include $10 with order for all normal items - heavy items, e.g. monitors add $15. 14 day money back guarantee Order by phone (use credit card). by fax or by mail. Unless insurance is declined it will be charged at 1% of total purchase. This is for your protection. PRICES VALID AT 1 JULY 1990 PtyLtd INTERFACE INTERFACE INTERFACE INTERFACE INTERFACE INTERFACE & & & & & & CABLE CABLE CABLE CABLE CABLE CABLE 349.00 399.00 * FINANCIAL SUBSCRIBERS ON 12TH DECEMBER WILL BE INCLUDED OVER -~ \I · ~ v I l \ -·-· . - ·-! \ .J.IUNl,:J"' $6500 Bose's radical new Lifestyle Music System is the great prize to be won. It comprises the Music Centre and one RF remote control (pictured), the Bose Acoustimass Powered Speaker System and a pair of Bose Lifestyle Powered Speakers (pictured). By taking out a subscription you could enjoy the benefits of this radical new music system which does not clutter up your living space with bulky hifi equipment and enables you to listen to two program sources at the- same time, in two zones, in your home. OFFER ENDS 30TH NOVEMBER 1990 30 SILICON CHIP WORTH OF PRIZES MUST BE WON - TM ® PLUS EACH MONTH ONE PAIR OF HIGH PERFORMANCE BOSE 101 MUSIC MONITOR SPEAKERS 3 SUBSCRIPTION PACKS FROM SILICON CHIP As part of this promotion, one pair of Bose 101 Music Monitor speakers, valued at $450, will be given away each month to a lucky subscriber. And even if you do win a pair of these speakers, you still go into the draw for the Bose Lifestyle Music System. Also each month, 3 new subscribers will get a SILICON CHIP subscription pack for free. This comprises a one year subscription to SILICON CHIP, one SILICON CHIP binder and one SILICON CHIP T-shirt in your size. Effectively, you get your annual subscription fee of $42 back and still go into the draw for the Bose Music System. HOW TO ENTER All current subscribers to SILICON CHIP at 1 2th December 1 990 are already in the draw. By taking a further one or two year subscription, they get another one or two entries . New subscribers enter by filling out the subscription coupon elsewhere in this issue and sending it together with their remittance of $42 (cheque, postal note or cred it card authorisation) to SILICON CHIP, PO Box 139, Collaroy, NSW 2097. Or fax it with a credit card authorisation to (02) 979 6503 . (1 ). The eompet1t1on 1s open only to Australtan residents with a cur rent. renewed or extendecl subscr 1pt 1on received by the last mail on 30th November . t 990. (2) Subscribers extendmg for an additional yeai arc enti tled to two entr ies (3). Subscribers wi th a two year subscr1pl\Gn are ent itl ed to two entries (4) Entries received alter the closing date will not be 111cluded. (5) Employees of S11Jcon Chip Pu!Jl1cat10ns Ply Ltd and Bose Australia lnG and their larnilles are not el1g1ble to ente1 {6). Soutt1 Au stI alIan residents do not tiave to purnt1a~e a sub scr1p tIon to enter but may enter only onee by subm itting th £m mime. ad RULES & CONDITIONS di ess ano a hand drawn laes1m1le of the subscnptmn to Silicon Chip Publlcatrons Plv Ltd. PO Box t 39. Collaroy. NSW 2097 (7). Prizes are not tran sferable or exchangeable and may not be con verted to cash (8 ). The Judges· decision 1s f1nc1I and no co11espondence will be entered into (9) The desrnptIon o! the competItmn and mstrw;tIons on how 10 enter form a part of the eom petItIon cond1t1o~s (1 0) The com-pet 1tIon beqin s on 29th Auqu st 1990 and closes with the last mail on 30th November. 1990. The draw will take place in Sydney on 17th December. 1990 and the winner w1II be notified by lcttergram. The winner will also be announced in The Australian on 20th Decernbe1, 1990 and in a late1 issue of SIucoN CHIP. (11 ). The ma1or prize 1s one Bose Lifestyle Music System and the total value of all prizes offe red is $6735.00. The promoter is Silicon Cl11p Publ1catrons Pty Ltd . Unrt 39/5 Ponderosa Parado. Warriewood NSW 2102 Permit TC90l2565 issued under the Lotteries and Art Unrons Act. 1901: Raffles Bingo Permrt Board Permit 90/1668 issued on t 618/90. ACT Permit No 90/1077 issued under the Lotteries 01 dinanc e. 1964. NT Permit NT0934/90 issued under Lotteries and Gam ing Act NOVEMBER 1990 31 sertion of AT-type hard drives without the need or expense of a separate controller. Do all those capabilies meet your needs? The 2500 XL is priced at $2499. For more information, contact your local Tandy store. Audio oscillator has switched frequencies Tandy desktop computer The new 2500 XL desktop computer from Tandy may look like a others on the market but its added extras will attract a good deal of interest. For starters, DeskMate and MSDOS 3.3 have been put into a ROM for instant turn-on operation. From there, a DeskMate applications disc gives the user a series of software packages including word process- ing, dictionary and spreadsheet facilities, calendar, address book, telecommunications, music, sound and draw programs. By plugging a microphone into 2500 XL's microphone jack, the user can record, store and play music or speech with the built-in ADC and DAG. The unit also comes with 1Mb of RAM, expandable to 16Mb using a memory manager package that is included. An Integrated Drive Electronics (IDE) connector allows in- Automatic Fax/phone switch from Access Want to run a fax machine on your phone line? If so, check out the Fax/Phone Switch II. It has no switches, just two LEDs on the front, one for power on and one to indicate a fax call. If you want to make a call either by phone or to send a fax, the unit automatically connects the right device to the line. For incoming calls, the unit greets the caller with a digitallyrecorded message to direct the call to either the fax or the phone. Line-in, fax and phone sockets 106 SILICON CHIP are provided at the back of the unit, together with a socket for the 12VAC power supply. The Fax/Phone Switch II comes with power supply, connectioIJ. cables and instruction manual. For further information, contact Access Communications, 33-35 Alleyne St, Chatswood 2067. Phone (02) 417 7474. If you're in the market for a low cost audio oscillator then take a look at this neat unit which is styled like a multimeter. Measuring 150 x 82 x 21mm, the Model 555 RC Oscillator puts out both sine and square waves. It has a 23-position selector switch and a 2-position range switch. On the xl range, the oscillator gives frequencies from 20Hz to 1.5kHz. Switching up to the xlO0 range gives frequencies from 2kHz to 150kHz. Accuracy is quoted at ± 3 % or better for frequencies from 20Hz to lO0kHz and ± 5 % or better from lO0kHz to 150kHz. The maximum output level is 1.2V RMS for sine waves and 8V p-p for square waves. Total harmonic distortion is quoted at 0.05% or less from 200Hz to 15kHz, 0.1 % or less from 50Hz to 30kHz, and 0.3% or better from 20Hz to lO0kHz. This is quite passable for a low cost oscillator. A useful feature is the sync signal output. This is a fixed output (1.2V RMS) which can be used for triggering an oscilloscope. Battery life is claimed at up to 50 hours with a 9V alkaline battery. A low battery LED lights when the battery is about to give up the ghost. Priced at $99.50, the Model 555 audio oscillator is available from your nearest Altronics dealer. Lithium battery packs from Geoff Wood Has your computer's backup battery died recently? Consider replacing it with one of these lithium batteries from Geoff Wood Electronics. That way, you shouldn't have to replace it for many years. Available in 3.6V and 6.8V packs, they come in a small plastic case and are fitted with polarised sockets on their leads. The 3.6V version sells for $29.50 and the 6.8V version for $39.95. For further details, contact Geoff Wood Electronics on (02) 428 4111 or drop in at 229 Burns Bay Rd, Lane Cove 2066. OnSight audio/video monitoring system If you would like to have a closed circuit TV (CCTV) system for your home, swimming pool or workplace, then this low-cost audio and B/W video monitoring system is the go. Called OnSight, it consists of a small charge-coupled-device (CCD) remote camera and monitor system, which also contains a 2-way audio system. All the hardware needed to install both the monitor and the camera are provided, including mounting brackets, 20-metre connecting cable and an AC adaptor. Instructions on how to connect the camera to either the monitor or to a VCR are supplied. The resolution of the CCD element is 120 lines x 162 columns which is more than adequate for CCTV work. Because of its small size, the camera unit can be discretely positioned so it doesn't attract interest. With the optional switchers and extra cameras and monitors, the system can expand to meet your requirements. The basic system shown costs $595. For further information contact Rod Irving Electronics in Melbourne on (03) 663 6151 or in Sydney at 74 Paramatta Rd, Stanmore 2048 on (02) 519 3134. Compact indoor FM antennas If you're having trouble pulling in some of the FM stations and you're only using a ribbon dipole antenna, then one of these indoor antennas from Jiloa could be of interest. The Terk FM2000 model is a passive loop antenna which can be used laid flat or upright. When laid flat it is more or less omnidirectional and when upright it is more directional, enabling you to discriminate against strong stations. Intended for 750 antenna sockets, it comes with an American F-connector and a 3000 balun transformer fitted with spade clips. The second unit, the Terk pi2, is a powered FM-antenna unit which contains a wideband 38dB low noise amplifier. It has the same directional qualities as the above unit and operates from a 9V DC supply. The gain of the unit can be adjusted over a wide range from - 20dB (to cope with powerful local stations) up to the maximum of + 38dB for remote locations. Both Terk units have been favourably reviewed in US magazines. The price of the PM2000 model is $69.95 including postage. For the pi2, the price is $199, again including postage . For further details, contact Jiloa Pty Ltd, PO Box 73, Glenhuntly, 3163. Phone (03) 571 6303 . SEPTEMBER1990 107 Low-voltage soldering iron Low-cost CAD package from Protel Most CAD packages around are not only quite expensive but they are also quite hard to use. The new Protel Easytrax 2 from Protel Technology is a fast low-cost package which can design and rout printed circuit boards up to 80 x 80cm. Available for the IBM XT/AT and compatibles and the Apple Maclntosh, Easytrax 2 has six track sizes which can be laid at any angle. An extensive library of pad shapes is included as well as the facility to create your own custom patterns. Also included are eight text sizes with both rotation and mirror image text for marking PC board patterns. It has a Postscript output as well as supporting plot, print and Gerber photoplotter options. Operation of the package is via mouse or by using menu-driven functions which cut down on the number of keystrokes. Easytrax 2 is particularly suited to the hobbyist and students, but is capable of producing professional results. It comes as a package of four 5.25-inch discs and a comprehensive 156-page manual with command summary appendices and instructions. The package is priced $395. Protel also has a range of powerful professional PCB design packages available as well as easy-touse schematic diagram production packages. For more information on Easytrax 2 or their other CAD packages, contact Protel Technology on (002) 73 0100 or by mail to PO Box 204, Hobart 7000. If you're one of the many people who don't like mains powered soldering irons or if you're just looking for a low-cost iron to throw in the back of the car, then this should suit you. This low-voltage iron will operate from 12-24V AC or DC, and comes fitted with a length of cable and a cigarette lighter plug. If you prefer, you can easily remove the plug and operate the iron from a 12V volt power supply. Rated at 8 watts, it's suitable for delicate jobs as well as those mobile emergencies. It has a lightweight feel and pencil-style grip. At only $11.50, why not get a spare for the workshop as well? It's available at any Jaycar Electronics store or by mail order from PO Box 185, Concord 2137. Phone (02) 747 1888. Power analyser for 3-phase analysis DB9 to DB15 converter cable If you're forever . making up special cables to do all those conversion jobs, here's one cable you won't have to make. This converter cable is 2 metres long with a DB9 plug at one end and a DB15 socket at the other. It currently sells for $29.95. For further information contact Geoff Wood Electronics (02) 428 108 SILICON CHIP 4111 or drop in at 229 Burns Bay Rd, Lane Cove 2066. Westinghouse Systems have recently released Voltech's new PM3000 3-phase power analyser which greatly simplifies the task of checking the harmonic distortion produced by switchmode power PowerSurge can Kill Your••• Computer, Facsimile, and Most Electronic Office Equipment ...and Don't Risk the Loss of Valuable Data ,~. ~~ Communications radio · covers FM as well This new radio from Sangean, the model Model ATS-808, has continuous frequency coverage from 150kHz to 30MHz plus the FM broadcast band. Tuning is easy, either with the rotary knob on the side or by keying in the frequency you want. As well, the ATS-808 has a 45-station memory which is probably more than most people will ever want. Among its many features are a dual-time clock, signal strength meter and battery indicator, all of which appear on the LCD display. Programming the memory positions is as easy as using a calculator. You just follow the steps given in the instruction manual. A built-in ferrite rod and a supplies and other non-linear loads. Measurements include watts, amps, volts, VA, VARs, crest factor, impedance and harmonics. The basic accuracy is 0.1 % from DC to lO0kHz. A high degree ofisolation is provided between inputs as well as between inputs and ground. This gives excellent common mode rejection telescopic antenna give good reception in most locations and you can connect an external antenna to pull in more distant stations. The radio only has a single loudspeaker but you can listen to the FM broadcast band in stereo via headphones. The unit also has a lock switch which disables all the controls and prevents any of the settings from being changed. This is handy if there are other people about who ar'e inclined to meddle with controls. Measuring 196 x 125 x 36mm, the receiver comes complete with a soft leather pouch, stereo headphones, instruction manual and a shortwave frequency guide. At $299, it is an attractive package. For further information, contact Access Communications, 33-35 Alleyne St, Chatswood 2067. Phone (02) 417 7474. Instal COMPUTER PROTECTOR A definite must for all electronic office equipment Available in the following Current Ratings: I Amp, 3 Amp, 6 Amp, &' JO Amps EX-STOCK DELIVERY! --------=• ~ I \!t~5!Lngb9~se SYSTEMS as well as allowing safe floating measurements. Measurements may be automated as the instrument has IEEE, RS232 and Centronics ports. For further details, contact the industrial products division of Westinghouse Systems, PO Box 267, Williamstown 3016. Phone (03) 397 1033. WESTINGHOUSE BRAKE & SIGNAL COMPANY (AUSTRALIA) LIMITED SIGNAL DIVISION 80·86 Douglas Pde, Williamstown, Victoria. (P.O. Box 267, Williamstown. Victoria. 3016) Phone (03) 397 1033. Fax (03) 3971861 Telex: 37 477 Wessys Vic (03) 3971033, NSW (02)5451322. Old (0 7) 275 :3188 SA (08) 212 3161 , WA (09) 446 8844 COM3 SEPTEMBER 1990 109 BIGGER THAN Exclusive to Force! Liquidation Stock Low-cost RGB Monitor. Attention Schools technical colleges, service techs and hobbyists. Features: 8" screen, .53mm Stripe pitch, ---=~~~~~~JA~l:~~ RGB analogue signal 1-SVp-p(Positive) or RGB TTL level, Scan: Hor.15.75kHz Vert. 40Hz, Video band width 624Hz ± 3d8 270 X200 lines resolution. Power= 12V (±.2Vl at 1.6 Amp. Spees. and circuit diagram. Weight: 4kg. Size: 190W x 195H x 299D PCB Mount Push Button Switches _*_ln_clu_d_ es_co_n_ne_ct_io_ n d_e_ tai_ls._ __, only s1 69 Momentary On, clicking action type Dimensions: 10mm X5mm(diam.) 1/2 Price! oldering Iron Stands only 20c each Stackable Thumbwheel Switches Tinid of having to carefully place your soldering iron somewhere amongst your work without burning anything? Then this is for you! Normally $12.95 now only S6.95 until sold out BCD 0-9 Should be over $6.00 each! Our price is only $1 .50 ea. and we only have 350 of them left. only s1 .50 240 Volt power '-----""'""" from 12 Volt DC with a Magnum Inverter Priceless when going camping or for when you are away from populated areas! There are three different versions of these inverters: t Power Point which gives 350 VA continuous and an intermittent rating of 650 VA Great for camping t Magnum 2000 which gives a 600 VA continuous and a surge rating of 2000 VA Heavy Duty version t Magnum 3000 which gives a 1200 VA continuous and S surge rating of 3000 VA Extra Heavy Duty t Available for either 12 or 24 Volt Chariots. S44 9 S8 g g 1250 Arlec P765 Variable Power Supply 5 - 15V DC at 2 Amps. Ideal for Hobby or special projects. Great for Schools, TAFE colleges and Electronic Whiz Kids Normally $109.95 Special ____________ s7995 ...._ __, ITT BIG SCREEN T.V. EXCLUSIVE. AT AN ALMOST UNBELIEVABLE PRICE! FULL SIZE 79 inch Screen T.V. for a Cinematic Experience that will stun you. The features of this magnificent television are almost as impressive as the price! We recommend that those who are currently renting or leasing such screens for business or pleasure, should seriously think of buying a ITT 203. It could soon pay for itself! I SCHOOLS I CONFERENCE CEN,RES I BUS\NESSES I SOC\Al CLUBS I COUCH POl AlOES I SPORl\NG BOO\ES 79 \NCHES {7 F,) SCREEN A, AR\D\CULOUS PR\CE OF ... ~~~\ic~~n Screen andUnit Stand Infra Red Remote control $49 50 COMPL p ETE 1-._;:_...::_7lACl~K=AGJE~-,A Models with similar features are currently selling for up to $10,000 Features: - ~~-1 I \,c The Projection unit uses NOVABEAM to give the brightest daylight operation.ITT 203 model has full stereo coming from a 30Watt per channel inbuilt Amplifier for really big sound to match the size of the screen. It has a 2.4 metre projection distance that allows the projecting unit to be well out of the line of sight, whether it be floor mounted or ceiling mounted. The ITT 203 is crafted in West Germany, giving the unit a level of reliability that other manufacturers can only dream of. In fact there are no other brands with as many features as the ITT 203 at a comparable price. The ITT has a brilliant picture quality that must be seen to be believed, so we recommend you to do come in to see it for yourself and you be the judge. The ITT 203 is also Genlockable, which to Video enthusiasts means a fantastic way to present information on screen together with another video source. Specifications: Screen 79"(200cm), Novabeam projection tubes, stereo sound, infra red remote control, Cable T.V. tuner, 32 programmable stations (VHF/UHF), Tone control, Balance control, Hypersonic stereo-wide circuit, Audio output is 30 Watts, Inbuilt speaker 130mm, DIN sockets for: Hi Fi, 2 headphones, External speakers and Video input. Materials for ceiling mounting are also supplied. :t:::::::::tit::::::::::1::I:::::::::::::::t::::::t1:::1:::i11i::i::::::■nil:ir.B~::::111itiniiJMa~iirasU.l:::e1:::111c.ll.il:l:II:::::::::::::i::::::::::::::::t:t::::::t::::111I:':'iI::::::::::::1::::::]:t:: C ADELAIDE 2o Wright St CHRISTIES BEACH 3 Ph·(08) 212 5505 24 Beach Rd. ' 382 3366 ..___ _ _ _ _ _ _ _ ____, LONSDALE ENFIELD 5 Somerset Circ. 445 Main Nth. 326 0901 349 6340 EL ECT RO NIC S BRIGHTON FINDON 500a Brighton Rd. 127 Findon Rd. 377 0512 3471188 MAIL & PHONE ORDERS Delivery charge of $8.00 for packages Rd. u~ to 10kg by mail or up-to 3Kg by overnight Air-bag. Min. order $10 Mobile transceiver has detachable front panel If you'd like to install a transceiver in your car or truck but just don't have the room in the dashboard, then !corn's new IC-901A DuoBander may interest you. It has a front panel which incorporates an LCD screen. A 3.5 metre optical fibre cable allows you to install the front panel on the dashboard and have the main unit elsewhere, such as in the boot. With full duplex capability, the IC901A is able to run crossband operation. It can also receive two bands simultaneously, with the unwanted band disabled by the mute switch when required. By purchasing one or a number of the optional band modules, the transceiver can cover any band from 28MHz to 1200MHz. The 2-metre FM/SSB/CW and 70cm FM bands are built in as standard. There are 12 memory channels plus one additional channel for each band. For more information on the IC901A, contact your nearest lcom dealer. cessor with 80385 cache memory controller, it is the ideal platform for a high speed file server or graphics workstation. On board memory is 4Mb of 80ns RAM with 32Kb of 25ns cache memory. The clock is switchable to 20, 25 or 33MHz in turbo mode and 8MHz or 12MHz with the cache disabed. An 80387 maths coprocessor can be fitted. There is a 32-bit expansion slot for up to 8Mb of memory, six 1/0 slots for 16-bit bus and two 1/0 slots for 8-bit bus. The unit also has a 7-channel direct memory access (DMA), three programmable timers, real-time clock and off-board battery. For further information, contact Electronic Solutions, PO Box 426, Gladesville, NSW 2111. Phone (02) 906 6666. Electronic spelling checker Combination logic probe & pulser This combination logic probe .a nd pulser is a handy unit for logic signal tracing and analysis. The logic probe section has an input impedance of 12okn and has a maximum input frequency of 50MHz, providing logic level indication with triangular red and green LEDs. The pulse output is taken from the little terminals on the probe body. Also provided are square wave and sync signal outputs. Two pulse rates are available, via a slide switch: 0.5 and 400Hz. Pulse current is 100mA for approximately 10µs duration, ensuring no damage is done to logic ICs. Operating voltage is 5 to 15V DC. 112 SILICON CHIP The price is $54.95 from Altronics Pty Ltd, 17 4 Roe St, Perth 6000. Phone (09) 328 1599. 386 motherboard has cache memory This motherboard from Electronic Solutions is claimed to be the fastest unit you can buy. Based on a 33MHz 80386 pro- If you can't spell "dikshunary" then this electronic dictionary could be just what you need. Called the SpellRight, it has 80,000 words stored on a 1Mb ROM. To use it, you type in the word the way you think it's spelt, and then SpellRight checks through and produces a list of possible words with their correct spelling. We checked it for " Australian conditions" and it spells "colour" the correct way, even if you try to spell it the wrong way! The unit is priced at $69.95 from David Reid Electronics, 127 York St, Sydney 2000. Phone (02) 267 1385. Twin-element PIR sensor either wide-angle or long-range coverage. The MH10 can do both, depending on which Fresnel lens is used. The MH10 has two infrared elements and this helps reduce the chance of false alarms. The wide angle coverage extends 15 metres over a 120 degree angle. Changing the Fresnel lens enables a narrow angle, long distance range of 40 metres. Current consumption is 25mA at 12V and it can be powered from 8.2V to 16V DC. The unit sells for $119. For further information, contact Force Electronics on (08) 212 5505; or by mail to 203 Wright St, Adelaide 5000. 6V supply. External mic, remote switch and earphone sockets are provided as well as a high/low/off voice actuation switch. The recorder retails for $99 and is available from Access Communications, 33-35 Alleyne St, Chatswood 2067. Phone (02) 417 7474. Voice-activated cassette recorder Passive infrared sensors are becoming more and more popular as intrusion detectors, providing This Fairmate CS-1104 cassette recorder is handy for recording meetings and lectures. It can be voice-activated via its internal microphone when recording so you don't waste any tape and it runs from four "AA" cells or an external UV PROCESSING EQUIPMENT KALEX LIGHT BOX • • • • • • Autoreset Timer 2 Level Exposure Timing Light Instant Light Up Safety Micro Switch Exposure to 22inx11in $850•00 Alarm system from Oatley Electronics If you're looking for an alarm system for either your car, home or business premises and you don't want to pay an arm or a leg for them, then you may like to consider this low-cost alarm system from Oatley Electronics. The system comes with two keyring style operating switches as well as all the hardware and ea bles needed to fit the alarm in most situations. The unit is priced at $140. For further information, contact Oatley Electronics on (02) 579 4985. PCB PROCESSING KALEX ETCH TANK • Two Compartment • Heater • Recirculation • (by Magnetic Pump) • Two Level Rack • Lid $750.00 UV MATERIALS 3M Scotchcal Photosensitive 8001 Red/Alum 8003 Black/Alum 8005 Black/Alum 8009 Blue/Alum 8130 Black/Gold 8006 Red/Transp 801 O Green/Transp 8011 Red/White 8012 Black/Transp 8013 Black/Yellow 8014 Blue/Transp 8015 Black/White 8016 Blue/White 8018 Green/White 8060 Black/Silver Pack Price Pack Price 250 x 300mm 300 x600mm 86.00 98.00 95.00 106.00 86.00 98.00 86.00 98.00 1 09.00 130.00 77.00 88.00 77.00 88.00 77.00 88.00 77 .00 88.00 77.00 88.00 77.00 88.00 77.00 88.00 77.00 88.00 77.00 88.00 77.00 88.00 ACCESSORY FILMS: 8007 Reversal Film 47.00 63.00 RISTON 3400 PCB MATERIAL SIZE INCHES 36 x 24 24 x 18 18'x 12 12 X 12 12x6 SINGLE SIDED 196.oo $48.oo $24.00 $16.00 $ 8.00 DOUBLE SIDED $124.oo $ 62.00 $ 31.00 $ 20.80 $ 11.00 ELECTRONIC COMPONENTS & ACCESSORIES • SPECIALIST SCHOOL SUPPLIERS All prices plus sales tax if applicable If LEX ""' 40 Wallis Ave .... ,...... 3079 (03) 497 3422 497 3034 Fax (03) 499 2381 SEPTEMBER 1990 113 - TEXTOOLIC SOCKETS PRINTER LEAD • Suits IBM' PC/XT, compatibles • 25 pin "D" plug (computer end) to Centronics 36 pin plug •1.8 metres FROM. Sc This inexpensive rang of modular Interlocking units enables a quick, easy way of experimenting with new circuits and ideas. There are two main units consisting of a terminal strip or distribution and a Central plug-in unit. • 100 holes P11000 .................... $2. 75 • 640 + 100 holes P11007.................. $14.95 • 1280 + 100 holes P11010 .................. $26.95 • 2560 + 700 holes P11018 .................. $69.95 ==Ill SUPA IC SPECIALS INSIDE THE IBM PC (Revised and expanded edition) -Peter Norton The widely ac clai med gui de to the LM30 1N LM308 LM348 0AC1408 JBM PC·s mnerworkrngs The latest ed1t1on now covers every model of the IBM micro PC. XT and AT. and every version of DOS from 1. 1 to 3 .0 B20080 DM2502 26LS31 4116 AY.S-8116 MSMS832 .. ..... .. $44 .95 ~ ~ 58725 6505 6845 7910 8212 8216 4161 4510 4520 4526 4536 4556 7416 7445 7474 74123 74157 74161 74FOO 74F32 74F109 12V DC FANS BO x 80 x 25.4mm 12V DC, 1.7 Watt, 0.14 Amps T12469 .................. $12.95 10+ fans only $11.95 each BALL BEARING FANS RECTANGULAR LEDS 1-9 10-99 100+ RED 20c 15c 12c GREEN 20c 15c 12c YELLOW 20c 15c 12c 12C ORANGE 20c 15c 74F153 Quality, fans for use in power amps, computers, hotspot cooling etc. Anywhere you need plenty of air. 240V 4 5/8" T12461 ... $14.95 • Gold machined pins • Extremely high quality • Antl-wlcklng • Ideal for professional use or where field service components is required. Cat.no. Description 1·9 10+ P10620 8 pin $1.20 $1 .10 P10624 14 pin $1.60 $1.40 P10626 16 pin $1.90 $1.80 P10628 18 pin $2.00 $1.90 P10630 20 pin $2.20 $2.00 P10632 22 pin $2.40 $2.20 P10634 24 pin $2.60 $2.40 P10640 28 pin $2.90 $2.70 P10644 40 pin $2.95 $2.75 74F521 74F533 74SOO 74S11 74S30 74S112 74S140 74S175 74H10 74S30 74540 74H61 74C926 74LS42 74LS74 74LS109 74LS139 74LSt62 PCB MOUNTING SCREW TERMINALS 74LS195 74LS241 7◄ LS258 74LS259 74LS573 (INTERLOCKING ENDS) These terminala feature interlocking enda to form any number of conectiona. Standard 5mm apacing pina • P10520 2 way 1-11 $0.75 • P10521 $1.0D' 10+ 7•LS2t3 74LS295 74LS393 74LS395 74LS640 6821 5S34AN lBOCPU 100+ ZSOCPUtO $0.70 $0.60 3way $0.90 $0.80 .so .25 .25 .25 .35 .10 .10 .10 .10 .60 .60 .60 115V 4 5/8" T12463 ... $14.95 ffl .60 .60 1.00 .40 .25 74F253 240V 3 1/2" T12465 ... $14.95 GOLD INSERT LOW PROFILE IC SOCKETS .so .so .so 74F283 115V 31/2"T12467 ... $14.95 1O+ fans (mixed) only $13.95 each 1•24 .40 .40 .75 .25 4.50 1.00 1.50 4.00 2.00 2.00 5.00 5.00 10 .00 1.00 1.00 74F157 74Ft81 74F194 74F257 ZBOAStO 8131 8156 8tLS95 8226 8255 8279 1.00 1.00 1.00 1.00 .10 .10 .15 .20 .25 .20 .10 .10 .10 .10 5.00 .20 .20 .20 .10 .20 .30 .30 .25 .25 .40 .30 .40 .40 .40 .70 2.50 ,.so 2.00 1.50 9.00 2.00 2.00 1.00 1.50 1.50 2.50 25+ .30 .30 P19029 .. .......... .... .. $14 .95 .60 • 3 metres .20 4.00 .eo P19030 ..... ..... .. ...... $19.95 1.00 3.00 1.50 1.50 4.00 4.00 8.00 .75 .75 .40 .40 • 10 LOW PROFILE IC SOCKETS Save a small fortune on these "Direct Import" low profile le sockets! PCB mounting solder tall. All tin plated phosphor bronze or berryllium and dual wipe for rellablllty. Cat. No. Description 1-9 10+ P10550 P10560 P10565 P10567 P10568 P10569 8 pln ............$0.20 $0.18 14 pln .......... $0.25 $0.20 16 pin ......... $0.25 $0.20 18 pin ......... $0.40 $0.35 20 pin ......... $0.40 $0.35 22 pin ......... $0.40 $0.30 P10570 24 pin ......... $0.40 $0.30 P10572 28 pin ......... $0.50 $0.40 P10575 40 pin ......... $0.50 $0.40 Leakproof and in 3 convenient alze•, theae long service life batteriea are ideal for burgular systema, emergency lighting or aa a computer backup power aupply ideal for many power aupply Ideal for many power need•. CatS1502912V1 2AH CABLES .80 .30 .20 .40 .20 .20 .20 .30 .OS .OS .OS .OS .30 .................."............$29.95 Cat S15031 12V 2 6 AH ----····$39.50 Y11085 Y11090 10 dB IN-LINE COAXIAL AMPLIFIER FLAT GREY RIBBON CABLE • Flat cable fo r IDC i:onnectors • m : metre .80 .80 W12614 l-9m. .so .so $1.90m .so .80 .80 W12616 .OS .OS .10 .15 .20 .15 .05 .05 .OS .05 4.00 .15 .15 .15 .OS .15 .25 .25 .20 .20 .35 .25 .30 .30 .30 .80 2.25 1.25 1.50 1.30 7.50 1.50 1.50 .80 1.20 1.25 2.00 $1.90m W12620 $2.50m W12624 $2.90m W12626 $3.60m W12634 $3.90m W12636 $1 .90m • 14way lQ+m. JQQ+m. $1.80m $1.20m •16way $1.80m $1.20m • 20 way $2.20m $1.50m • 24 way $2.70m $1.70m . • 26 way $3.30m $2.20m Reduces lose from aplitters and long cable runa. Suitable for use with antennas, coaxial feed lines and VCR's A/C lldaptor included SPECIACATIONS: Frequency Range: S-900MHz Gain:10dB Power requirement&: 12V A/C Adaptor included Input lmpendance: 75ohm Output lmpendence : 75uhm Ct.~.L15043 .........$39.95 • 34 way $3.60m $2.30m • 36 way $1 .80m $1.20m VOLTAGE REGULATORS BARGAINS W12640 • 40 way $4.90m $4.00m $2.80m W12650 $5 .50m • 50 way Description $4.90m $2.90m C $11.50 $7.50 $6.90 $6.50 $6.~~ .90 90 lO COMPUTER CABLE • Six conductor shielded computer Interface cable • m :metre W12670 • CIC6 1-9 m 10+ m 100+ m $1.30m $1.10m $1.00m .J ,➔ .90 Y11 v11r;;o v;1033 Y11042 Y11050 Y11055 Y11070 Y11072 Y11080 These ZIF socketa are perfect for inaerting and removing EPROMS so H not to damage the IC pina. 1-9 10+ •16 pin P17016 ....".$16.95 $13.95 •24 pin P17024..... ".$19.95 $18.50 •28 pin P17028..... ".$26.95 $24.95 •40 pin P17040........$34.95 $32.95 .so .so 1MHz 1.8432MHz 2MHz 2.3040 MHz 2.:4576 MHz 2. 7648 MHz 3MHz 3.5795 3.9- y~ Y11 metres P19034 ........ .......... $39.95 CRYSTALS RECHARGEABLE 12V GELL BATTERIES (ZERO INSERTION FORCE) ,z$3.90 ,"1Hz$4.90 . "1Hz $4.90 .. 15 MHz $4.90 4.9152 MHz $6.90 4.9562 MHz $4.90 5MHz $4.90 5.0688MHz $4.90 6.144 MHz $4.90 8.00 MHz $4.90 8.86723MHz $4.90 12.00 MHz $4.90 14.318 MHz $4.90 16.00 MHz $4.90 18.432 MHz $4.90 20.00 MHz $4.90 W12672 • CIC9 1-9 m 10+ m 100+ m $1.60m $1.SOm $1.20m W12674 • CtC12 1·9 m 10+ m 100+ m $2.50m $2.20m $1.90m W12676 •CIC16 1-9 m 10+ m 100+ m $3.50m $3.20m $2.SOm W12678 • CIC25 1-9 m 10+ m 100+ m $3.90m $3.40m $3.00m 7805UC 7812UC 7815UC 7905UC 71n2UC 7!n5UC 78L05 78L12 LM324 555 741 1-9 10+ $0.50 $0.50 $0.50 $0.60 $0.60 $0.60 $0.45 $0.45 $0.45 $0.45 $0.45 $0.55 $0.55 $0.55 $0.40 $0.40 $1.00 $0.90 $0.40 $0.38 $0.50 $0.45 ** ,;-,-· --.I~ ~ . 2&4WAY RS232 DATA TRANSFER SWITCHES CPF CONTINUOUS POWER FILTER SPIKE ARRESTOR The Fortran CPF Filtered Electroni c Spike Prolector provides a protective electronic barner for microcomputers. printers. telephone systems and rnodems electronic typewriters audio and stereo systems and other sensitive electron ic equipment The CPF provides protect1on from dangerous electrical spikes that can ca1Jse anything from obv,ous dafllage (hke immediate equipment la1lure ) to less obvious harm that can drastically shorten a system 's life CPF's superior c1rcu11ry design and semi conductor technology responds 1ns1antly to any potenllally damaging over-voltage . ensuring safe trouble free operation Additionally. CPFs filtering capability helps ehminate troublesome and annoying mlerterence. general hash cre.ated by small motors. fluorescent lamps. and the like 1hat threaten the performance and shOrten equ ipment hie of unprotected electronic companents. SPECIFICATIONS : Electrical rating : 220-260 volts (AC) 50Hz 10 Amp Spfke/RFI Protection : 4 .500 amps for 20m/second pulses Maximum clamping voltage: 275V differential mode . CatX10088 $69.95 RS232 BREAK OUT BOX A simple way of monitoring AS232 interlace lead activity. Interface powered. pocket size for circuit testi~g. monitoring and patching 1O srgnal powered LED's and 2 spa res. 24 switches enables you to break out circuits or reconligUre and patch any or all lhe 24 active positions. SPEC IFICATIONS: Connectors : 0825 plug on 80mm ribbon cable and 0825 socket. Indicators : Trtcolour LED's for TD . RD . RTS. CTS. DSR . CD. TC. AC. OT A. (E)TC . Jumper Wires: 20 tinned end pieces Power : !nterface power. Enclosure : Black. high impact plastic. Dimensions : 85 x 95 x 30mm X15700 $94.95 g J\ .. RIBBONS ... . ~c.;] ~/\', Quality paper at a low price! 2.000 sheets ol 70 gsm bond paper. Cat C21003 11' 9 112" Cat C2 1005 15, 11 $67.95 $41.00 KEYBOARD EXTENSION LEAD 5 Pin Din plug and socket P19038 .. ... .. ... ..........$6.95 . . -":',, 9 PIN TO 25 PIN CONNECTOR ADAPTORS N EW 1The ideal soluuon 1 Features gold plated pins X15668 0 89 Plug to 0825 Socket X 15669 0 89 Socket to 0825 Plug each $8.95 · PRINTER RIBBONS TO SUIT: • CP80 , sxao, DP80 , BX100 , BX100 , MB100 1·9 C22036 .. $19.95 • MX80, FX80 , RX80 , FX800, MX70 , MX80 . LX800 1-9 10+ C22031 ....$16.95 $15.25 • MX100, FX100, RX100.LQ1000 1·9 10+ C22002 ....$19.95 $17.95 1-9 C22003 .. $12.95 • C ITOH 8510• 1550 1-9 C22051 ..$13.95 DELUXE PRINTER STAND • Restores order 10 your work area w1lhout occupying extra space • Feed s and refolds paper under the pnn1e r automatically • AdJustable paper defl ectors ensure smooth flow of paper • Made ol moulded plastic • Suitable lor most printers C21058 (80 colum n) $69.95 10+ $11.95 10+ $12.50 $99.95 3½" FLOPPY DISK DRIVE EXTENSION CABLE • IBM" compatible • 0837 Male to 34 IOC connector • Length 0·5 metres P19046 $99.95 X10086 .....................$69.95 2&4WAY CENTRONICS DATA TRANSFER SWITCHES Save time and hassles of constantly c~ anging cables and leads around with these inexpensive data tra nsfe r switches. These data switches support the 36 pin centronic interface used by Centronics. Printronics . Data Products, Epson. Micronics. Star. and many other printer manufacturers • No power required • Speed and code transpa rent • Two/Four position rotary switch on front panel • Three/Five interface connections on rear panel • Switch comes standard with female connector • Bale locks are standard 2 WAY (X19 130) only $49 4 WAY (X19135 ) onlv $59 LMis?~ . ·.-•·.· ~ UV EPROM ERASER Erase your EPROMs quickly and safely. This unit is the cost effective solution to your problems. It will erase up to 9 x 24 p in d evices in complete safety, in abo ut 40 minutes (less time for Jess ch ips) • Chip drawer has conductive loam pad • Mains powered • H igh UV intensity at chip surtace ensures EPROMs are thoroughly erased Without timer X14950 ............ ....... $129 With built-in timer X14955 ..... ....... ....... $159 DUST COVER Keep your computer and accessories free of d u st and grime while not in use POCKET AUTO AB SWITCHES • Pocket size, au to-scann ing • A llows 2 PCs to share o ne Printer 6 PROTECTED POWER OUTLETS Ideal tor protecting personal computers, video equipment, colour TVs, amplifiers, tuners, graphic equalisers, CO players etc SPECIFICATIONS: , Electrical rating: 240V AC, 50Hz, 10A , 3 x Metal Oxide Varistors (MOV) • Maximum clamping Voltage: each MOV: 71 0 volts at 50 amps , Response time: Less than 25 Nanoseconds. $39 only $49 co ',! -:::•~ .;,:, XT HD CONTROLLER $129 AT HD CONTROLLER $199 RS232/ SERIAL/ CLOCK •••... ..••..•••••••••. .. •.. $49 MONO/ COLOUR CARD$96 MULTI 110 ••••• •.....•......•..•. $99 512K RAM..................•... $59 DIAGNOSTIC ................. $750 TTL/ PRINTER. ............... $l3 9 RAM 2M AT EXTIEXP .. $225 8M AT EXT/ EXP ........... $ 325 m iii 4 PORT SERIAL. ••.•.•••. .••• $89 VGA 2561<-.. ...•••..........•... $199 VGA 512K ..........••••......... $ 299 ■ VOICE MAIL ................... $245 PRINTER CARD..•........... $29 EGA CARD ...........•••.••..... $139 2 WAY FDO CONT. (360K) ..................... .... .•••. 539 RS232 SERIAL/ CARD ..... .....•...•.••••••........ $ 39 XT* Cover Set C21066 .......... ........$14.95 AT' Cover Set C21068 ..... ............. $16.95 LEADS (3S0·1.44M) SMART DRIVE ADAPTER IDEIFDC .......... $89 SMART DRIVE ADAPTER IDE 110 IFDC•. . $119 C21085 .... ...... ........$14.95 RS232 GENDER CHANGERS • Saves modifying or replacing non-malmg RS232 cables. • All 25 pins wired straighl through Cat X15650MaletoMa le Cat X15651 Male to Female Cat X15652 Female to Female Normally $14 .95 each OnlY $8.95 MOTHERBOARDS XT 10M MINl... ..•.•••..•.....•..••.. $99 XT31M •... ....•.......•••.•••....•••.. $199 XT 12M STD. SIZE .•.. •••••. •••. $179 SUNTEC AT 12M.. ••••.....••••• $375 RODIRVING ELECTRONICS SYDNEY : 74 Parramatta Hd . Slanmore. 2048. Phone (02) 519 3134 Fax (02) 519 3868 RS232 MINI TESTER • Male to female connect10ns • All pm w1red straight through • Dual colour LED 1nd1cates ac1 1v11y and d1rect1on on 7 hnes • No batteries or power required T.D. Transmit Data O.S.R. Data Set Ready A O Receive Data C .D. Carrier Detect R.T.S . Request to Send D TA. Data Term1na t Ready C.T.S . Clear to Send Cat X15656 Normally $39.95 fl COPYHOLDEY (YU-H32) • Adjustab.l~ ar~s allows. easy pos1t1omng • Copy area 91 12" x 11" • Sliding line guide • Clamp mounting C21062 ........... $39.95 MELBOURNE : 48 A-Seekell St Phone (03) 663 6151 NORTHCOTE, 425 High S1. Phone (03) 489 8866 CLAYTON : 56 Renver Rd . Phone (03) 543 7877 MAIL ORDER& CORRESPONDENCE , P.O. Bo, 620. CLAYTON 3168 Orde r Holl ine : 008 33 5757 (Toll tree. striclly orders only) lr,quiries: (03) 543 7877 Telex : AA 151938 Fax: (03) 543 2648 MELBOURNE DEALERS MICRODOT 177 SPRINGVALE ROAD NUNAWADING. Ph.804 1255 GREENSBOROUGH COMPUTERS 67 GRIMSHAW ST (au Howard at) Ph: 434 6168 BRISBANE DEALER VRC COMPUTER SERVlCE 647 LUTWYCHE RD LUTWYCHE, 4030 ADELAIDE DEALER MI CROTRONICS 305 MORPHETT ST ADELA! DE, 5000 All sales tax exempt orders and wholesale inquiries to: RITRONICS WHOLESALE . 56 Renver Road. Clay1on . Phone , (03) 543 2166 (3 li nes) Fax: (03) 543 2648 For postage rates refer to other R.I.E advertisement PRINTER LEAD Remove ugly paper feed edges quickly and clean ly with this simple little gadget Only $24.95 ..... :$ 129 2 WAY FDD CONT. (360-1.44M) ................ ..... $80 CLOCK CARD .....•........... $ 39 • Suits IBM" PC/XT, compatibles • 25 p in " D" plug (computer end) to Centronics 36 pin plug RIPPER STR IPPER CENTRONICS GENDER CHANGERS • Female to Female. • Saves modifying or repl acing non-mating Centronics cables. • All 36 pins wired straight through Cat. X15663 Male to Ma le Cat. X 15661 Male to Female Cat. X15664 Fema le to Fema le Normally $33.95 , GAMES...... ............• $29 AT SIP GAMES .............•. $59 4 \"/AV FDD CONT. SPECIAL. ONLY $32.95 Serial model : MS-201 - Host-powered X19150 .................. $79.95 Parallel model : MP-201 Protocol transparent X19155 .................. $89.95 P19045 'e;';~e~o;~;~~~r20 only 4 WAY ea, x19125 NATIONAL PANASONIC KXM110 PRINTER RIBBON C22034 ............... .. .$19.95 M AGIC STAGE • IBM· compalible • 0837 Mate to 34 way edge con nector • Length 0·5 metres 2 DUST COVERS Hi. ~~j A working bench for your Mouse. •High quality ABS plastic and anti-static rubberised top •Stationary holder ,Includes pull-o u t shelf tor Mouse devices that need to share a third or fifth, then these inexpensive data transfer switches will save you the time and hassle of constantly changing cables and leads around • No power requ ired • Speed and code transparent • Two/Four pasition rotary switch on front panel • Th re e/Five interface connections on rear panel • Switch comes standard w~h 10+ $17.95 • LX80 $29.95 ~~ ~~- SPEC IFICATIONS : Voltage 240V Nommal Total Energy Rating · 150 1oules Response Time: 1Ons Protection Level. 350V peak COMPUTER PAPER • • Keeps your paper and print-out s neat and orderly • Transparent cover makes 11 easy to check on paper supply • Paper can be fed from the centre or the rear according to the design ol the printer • Removable drawer which allows paper to be changed without moving the pmuer • Retractable rear basket makes pnnt -out collection fast and convenient • Sullable lor most pr inters Surges and spikes are caused not only by lightning strikes and load switchi ng but also by other equipment be ing switched on and off . such as fluorescent lights . electric motors fridge freezers, air conditioners. etc For effective protection such spikes must be stopped before they reach your equipment. Simply plug The Bunon into an outlet and it will protect all equipment plugged into adjacent outlets on the same branch circuit. The Button employs unique metal oxide varister technology and will dissipate 150 Joules al electrical energy . (nearly twice that of comparable su rge arresters .) $36.95 ~~ ENCLOSED PRINTER STAND THE BUTTON SPIKE PROTECTOR If you have two or four compatible ' •1.8 metres P19029 .................. $14.95 • 3 metres P19030 .....•............ $19.95 • 10 metres P19034 ..................$39.95 COPY HOLDER (YU-H33) • Copy area 9 1/2" x 11·· • Shdmg li ne guide • Flat metal base C21060 Errors and omissions excepted . Prices and specifications subject to change . 1eM·.PC·. xr ,AT· are re,g,ste,edtrademarksol 1ntema1oona1 Bus111ns Machines ·Ap()le ,s a ''9'51e<ed ir.ietnark •0eoote5 ,eg,s1ered 11admantsollheor1espect..,.owne,s ACT Where to buy Silicon Chip SILICON CHIP is on sale every month, usually in the week preceding the month of issue. For example, the October issue is due on sale in the last week of September. You can purchase your copy at your newsagent or at the following electronic retail outlets. NEW SOUTH WALES Chantronics, 740 Horsley Drive, Smithfield, 2164. Phone (02) 609 7218. Clubman Electronics, Shop A, 134 Great Western Hwy, Blaxland, 277 4. Phone (047) 39 3903. Coifs Harbour Electronics, 195 High St, Coifs Harbour, 2450. Phone (066) 52 5684. Dauner Electronic Sales, 51 Georges Crescent, Georges Hall, 2198. Phone (02) 724 6982. David Reid Electronics, 127 York St, Sydney, 2000. Phone (02) 267 1385. Dick Smith Electronics, Cnr Swift & Young Sts, Albury, 2640. Phone (060) 21 8399. Dick Smith Electronics, T55 Terrace Level, Bankstown Square, 2200. Phone (02) 707 4888. Dick Smith Electronics, Shop 1, 65/75 Main St, Blacktown, 2148. Phone (02) 671 7722. Dick Smith Electronics, 2 Denison St, Bondi Junction , 2022. Phone (02) 387 1444. Dick Smith Electronics, Shop 2, 18 Cross St, Warringah Mall, Brookvale, 2100 Phone (02) 905 0441. Dick Smith Electronics, Shop 8, Endeavour Square, Dumeresq St, Campbelltown, 2560. Phone (046) 27 2199. Dick Smith Electronics, Shop 235, Archer St Entrance, Chatswood Chase, 2067. Phone (02) 411 1955. Dick Smith Electronics, 147 Hume Hwy, Chullora, 2190. Phone (02) 642 8922. Dick Smith Electronics, 164 Pacific Hwy, Gore Hill, 2065. Phone (02) 439 5311. Dick Smith Electronics, 99 Donnison St, Gosford, 2250. Phone (043) 25 0235. Dick Smith Electronics, 4 Florence St , Hornsby, 2077. Phone (02) 477 6633. Dick Smith Electronics, 124 Forest Rd, Hurstville , 2220. Phone (02) 580 8622. Dick Smith Electronics, Elizabeth Drive & Bathurst St, Liverpool, 2170. Phone (02) 600 9888. Dick Smith Electronics, 450 High St, Maitland , 2320. Phone (049) 33 7866. Dick Smith Electronics, 621-627 The Kingsway , 116 SILICON CHIP Miranda, 2228. Phone (02) 525 2722. Dick Smith Electronics, 173 Maitland Rd, Tighes Hill, Newcastle, 2300. Phone (049) 61 1896. Dick Smith Electronics, Cnr Lane Cove & Waterloo Rds, North Ryde, 2113. Phone (02) 878 3855. Dick Smith Electronics, George & Smith Sts, Parramatta, 2150. Phone (02) 689 2188 . Dick Smith Electronics, Cnr. Henry & Riley Sts, Penrith, 2750. Phone (047) 32 3400. Dick Smith Electronics, 818 George St, Railway Square, Sydney, 2000. Phone (02) 211 3777. Dick Smith Electronics, 124 York St, Sydney City, 2000. Phone (02) 267 9111. Dick Smith Electronics, Regent Cinema Complex, Kable Ave, Tamworth 2340. Phone (067) 66 1711. Dick Smith Electronics, 263 Keira St, Wollongong, 2500. Phone (042) 28 3800. Geoff Wood Electronics, 229 Burns Bay Rd, Lane Cove, 2141. Phone (02) 427 1676. Jaycar Electronics, 11 7 York St, Sydney, 2000. Phone (02) 267 1614. Jaycar Electronics, 188-192 Pacific Hwy (Cnr. Bellevue Ave), Gore Hill, 2065. Phone (02) 439 4799. Jaycar Electronics, 121 Forest Rd, Hurstville, 2220. Phone (02) 570 7000. Jaycar Electronics, 115-117 Parramatta Rd, Concord, 2137. Phone (02) 745 3077. Jaycar Electronics, Corner Victoria Rd & Church St, Parramatta, 2150. Phone (02) 681 3377. Leeton Audiotronics, 93 Pine Ave, Leeton, 2705. Phone (069) 53 2081. Novocastrian Electronic Supplies, 24 Broadmeadow Rd, Broadmeadow , 2292. Phone (049) 62 1358. Rod Irving Electronics, 74 Parramatta Rd , Stanmore , 2048. Phone (02) 519 3134. Sheridan Electronics, Shop 30 , Central Plaza, Patrick St, Blacktown, 2148. Phone (02) 621 1494 Sport Sound, Shop 2, Raymond Mall, Springwood, 2777. Phone (047) 51 5852. Tomorrow Electronics, 68 William St, Gosford, 2250. Phone (043) 24 7246. Dick Smith Electronics, Unit A, Lake View Square , Belconnen , 2617. Phone (06) 253 1785. Dick Smith Electronics, 98 Gladstone St, Fyshwick, 2609. Phone (06) 280 4944. VICTORIA All Electronic Components, 118-122 Lonsdale St, Melbourne, 3000. Phone (03) 662 3506 . Dick Smith Electronics, Creswick Rd & Webster St, Ballarat, 3350. Phone (053) 31 5433. Dick Smith Electronics, 145 McCrae St, Bendigo, 3550. Phone (054) 43 0388. Dick Smith Electronics, Shop 46, Central Main St, Box Hill, 3128. Phone (03) 890 0699. Dick Smith Electronics, 260 Sydney Rd, Coburg , 3058. Phone (03) 383 4455. Dick Smith Electronics, Shop 1, 178 Lonsdale St, Dandenong, 3175. Phone (03) 794 9377. Dick Smith Electronics, Hawthorn & Nepean Highway, East Brighton, 3186. Phone (03) 592 2366. Dick Smith Electronics, 1150 Mount Alexander Rd, Essendon, 3040 . Phone (03) 379 7444. Dick Smith Electronics, Shop 11 /13 Footscray Plaza, Footscray, 3011. Phone (03) 689 2055. Dick Smith Electronics, Nepean Hwy & Ross Smith Ave, Frankston, 3199. Phone (03) 783 9144. Dick Smith Electronics, 125 Moorabool ·st, Geelong, 3220 . Phone (052) 23 2711. Dick Smith Electronics, Shop 1, 399 Elizabeth St, Melbourne City, 3000. Phone (03) 326 6088. Dick Smith Electronics, Bridge Rd & Blvd, Richmond , 3121. Phone (03) 428 1614. Dick Smith Electronics, Shop 2, 141 Maroonda Hwy, Ringwood, 3134. Phone (03) 879 5338. Dick Smith Electronics, Springvale & Dandenong Rds, Springvale, 3171. Phone (03) 547 0522. Echuca Technical Service, 220 Pakenham St, Echuca, 3564. Phone (054) 82 2956. Jaycar Electronics, 45 A'Beckett St, Melbourne , 3000. Phone (03) 663 2030. Jaycar Electronics, 887-889 Springvale Rd , Springvale, 3171. Phone (03) 547 1022 Resurrection Radio, 51 Chapel St, Prahran, 3181. Phone (03) 529 5639. Rod Irving Electronics, 48 A'Beckett St, Melbourne, 3000. Phone (03) 663 6151. Rod Irving Electronics, 425 High St, Northcote , 3070. Phone (03) 489 8866. Sound Australia, 28 Walker St, Dandenong, 3175. Phone (03) 791 1622. Stewart Electronics, 44 Stafford St, Huntingdale, 3166. Phone (03) 543 7238 QUEENSLAND Dick Smith Electronics, 157-159 Elizabeth St, Brisbane City, 4000. Phone (07) 229 9377. Dick Smith Electronics, 170 Logan Rd, Buranda, 4102. Phone (07) 391 6233. Dick Smith Electronics, 42-44 Florence St , Cairns, 4870. Phone (070) 31 1515. Dick Smith Electronics, Gympie & Hamilton Rds , Chermside, 4032. Phone (07) 359 6255. Dick Smith Electronics, Second Level Western Entrance, Redbank Shopping Plaza, Redbank, 4301. Phone (07) 288 5599. Dick Smith Electronics, Queen Elizabeth Rd & Bernard St, Rockhampton, 4700. Phone (079) 27 9644. Dick Smith Electronics, Gold Coast Hwy & Welch St, Southport, 4215. Phone (075) 32 9033. Dick Smith Electronics, Bowen & Ruthven Sts, Toowoomba, 4350. Phone (076) 38 4300. Dick Smith Electronics, Kings Rd & Woolcock St. Townsville, 4810. Phone (077) 72 5722. Dick Smith Electronics, Cnr Pacific Hwy & Kingston Rd , Underwood, 41 19. Phone (07) 341 0844. Jaycar Electronics, 144 Logan Rd, Buranda, 4102. Phone (07) 393 0777. SOUTH AUSTRALIA Dick Smith Electronics, 252 Pulteney St, Adelaide, 5000. Phone (08) 232 1200. Dick Smith Electronics, 688 Port Rd , Beverley, 5009. Phone (08) 347 1900. Dick Smith Electronics, 1267 South Rd, St Marys, 5042. Phone (08) 277 8977. Dick Smith Electronics, Shop T25, Elizabeth City Centre , 5113. Phone (08) 255 6099 . Dick Smith Electronics, Main North Rd & Darlington St, Enfield, 5085. Phone (08) 260 6088. Eyre Electronics, 15 Forsyth St, Whyalla, 5600. Phone (086) 45 4764. Force Electronics, 203 Wright St, Adelaide, 5000 . Phone (08) 212 5505. Force Electronics, 500a Brighton Rd, Brighton, 5048. Phone (08) 377 0512. Force Electronics, 24 Beach Rd , Christies Beach, 5165. Phone (08) 382 3366. Force Electronics, 445 Main North Rd, Enfield, 5085. Phone (08) 349 6340. Force Electronics, 127 Findon Rd, Findon, 5023 . Phone (08) 347 1188. Force Electronics, 5 Somerset Circuit, Lonsdale, 5160. Phone (08) 326 0901. Microtronics, 305 Morphett St, Adelaide , 5000. Phone (08) 212 1799. Selectronics, BI LO Shopping Centre, Mannum Rd, Murray Bridge, 5214. Phone (085) 31 0445 WESTERN AUSTRALIA Altronics, 17 4 Roe St, Perth, 6000. Phone (09) 328 1599. Dick Smith Electronics, Wharf St & Albany Hwy, Cann ington, 6107. Phone (09) 451 8666. Dick Smith Electronics, 68 Adelaide St, Fremantle, 6160. Phone (09) 335 9733 . Dick Smith Electronics, William St & Robinson Ave, North Perth, 6006. Phone (09) 328 6944. Dick Smith Electronics, Raine Square, 125 William St, Perth City, 6000. Phone (09) 481 3261. Today's Electronics, 295 Hannan St, Kalgoorlie , 6430. Phone (090) 21 5212. TASMANIA Dick Smith Electronics, Shop 48, Lower Level, Cat & Fiddle Arcade , Hobart, 7000. Phone (002) 31 0800. Fluke 45 Digital Multimeter with all digital multimeters the accuracy of any measurement is always less than indicated by the resolution. As you would expect, the Fluke gives its best accuracy on DC measurements: ± .02%. For DC current and resistance, the accuracy is generally ± .05 % while for AC voltage and current, the accuracy varies depending on the signal frequency. Interestingly, the Fluke 45 can tolerate quite high peak AC voltages when measuring DC voltage. For example, on the 100mV to 1000mV DC range, the maximum allowable peak AC is 20 volts. For the 10V to 1000V DC ranges, the maximum allowable peak AC is 1000 volts. Production line use The Fluke 45 is ideally suited to production line use where it is necessary to check that unit parameters are within limits. You can set the upper and lower limits and then the Fluke will indicate the reading on the primary display, together with a Hi, Lo or Pass indication on the second display. This is handy where unskilled operators are responsible for the testing. Computer control Finally, the other major feature of the Fluke 45 is that it can be controlled by a computer using either the built-in RS-232 interface or optional IEEE-488 interface. Also available is a floppy disc with a full range of commands. Called ctd from p.19 "Quickstart 45", it operates on any IBM or compatible machine using DOS 2.1 or later. We put through a range of control functions and found that it works very well. You can vary the rate at which measurements are made (anything from 1 per second upwards) and stored to disc for later analysis - a very powerful tool. Summing up As noted at the beginning of this article, we have space only for a brief overview of this instrument. It is a highly flexible and accurate laboratory instrument, easy to use for most functions and supported by a very well written instruction manual. For any workshop or laboratory wanting a highly flexible ,multimeter with a step-up in facilities over Fluke's fine 80 series meters, the model 45 is the one to go for. Best of all, all that measurement capability comes pretty cheaply. It is priced at $1216 plus tax. The Quickstart 45 software is available at $200 plus tax, the optional IEEE interface at $310 plus tax, and the battery pack at $245 plus tax. Also available is a convenient padded vinyl carrying case priced at $100 plus tax. For further information contact Philips Test & Measurement, 25-27 Paul St, North Ryde , NSW 2113. Phone (02) 888 0416 or contact Tech-Fast T&M Pty Ltd, 14B Maxwell St, Turramurra, NSW 2074. Phone (02) 988 3865. ~ Is Your Product Getting The Exposure It Deserves? NORTHERN TERRITORY Dick Smith Electronics, 20 Stuart Hwy, Stuart Park, 0820. Phone (089) 81 1977. Also at most newsagents throughout Australia. Our newsagency distributor is Network Distribution Company which has offices in every state capital. Back issues of SILICON CHIP are available from Silicon Chip Publications Pty Ltd. See the back issue page elsewhere in this issue. Electronics retailers who would like to sell SILICON CHIP should contact our Sales Manager, Paul Buchtmann, on (02) 979 5644 or write to us at SILICON CHIP, PO Box 139, Collaroy Beach, 2097. Consumers need to see your product if you want them to buy it Contact Paul To Reserve This Space - (02) 982 9553 SEPTEMBER1990 117 Silicon Chip BACK COPIES February 1988: 200 Watt Stereo Power Amplifier; Deluxe Car Burglar Alarm; End Of File Indicator For Modems; Low Ohms Adaptor For Multimeters; Line Isolation Unit For Phone Patch; Easy Tips On Headphone Repair. March 1988: Remote Switch For Car Alarms; Telephone Line Grabber; Endless Loop Tape Player; Build Your Own Light Box; New Life For RadioCassette Players; Old-Time Crystal Radio. April 1988: Walkaround Throttle For Model Railroads, Pt.1 ; pH Meter For Swimming Pools; Slave Flash Trigger; Headphone Amplifier For CD Players; What Is Negative Feedback, Pt. 1 ; Mobile Antennas For The VHF & UHF Bands. May 1988: Optical Tachometer For Aeromodellers; High Energy Ignition For Cars; Ultrasonic Car Burglar Alarm; Walkaround Throttle For Model Railroads, Pt.2; Designing & Building RF Attenuators; Motorola MC3334P High Energy Ignition IC Data. June 1988: Stereo Control Preamplifier (Uses LM833), Pt.1; Breakerless Ignition For Cars Using Hall Effect Pickups; Mega-Fast Nicad Battery Charger; Automatic Light Controller (Uses PIR Detector); RF Sniffer Probe & Preamplifier; What Is Negative Feedback, Pt.2 . July 1988: Stereo Control Preamplifier, Pt.2; Fitting A Fuel Cut-Off Solenoid; Booster For TV & FM Signals; The Discolight Light Show, Pt.1; Tone Burst Source For Amplifier Headroom Testing; National Semiconductor LM833 Op Amp Data; What Is Negative Feedback, Pt.3. August 1988: Building A Plasma Display; Universal Power Supply Board; Remote Chime/Doorbell; High Performance AC Millivoltmeter, Pt .1; Discolight Light Show, Pt.2; Getting The Most Out Of Nicad Batteries; Data On Insulated Tab Triacs. September 1988: Hands-Free Speakerphone; Electronic Fish Bite Detector; High Performance AC Millivoltmeter, Pt.2; Vader Voice; Motorola MC3401 8 Speakerphone IC Data; National Semiconductor LM 1 2 1 50W Op Amp Data & Applications; What Is Negative Feedback, Pt.4. October 1988: Stereo FM Transmitter (Uses Rohm BA1404); High Performance FM Antenna; Matchbox Crystal Set; Electronic House Number; Converting A CB Radio To The 28MHz Band; Oueensland's Powerful Electric Locomotives. November 1988: 120W PA Amplifier Module (Uses Mosfets); Poor Man's Plasma Display; Automotive Night Safety Light; Adding A Headset To The Speakerphone; How To Quieten The Fan In Your Computer; Screws & Screwdrivers, What You Need To Know; Diesel Electric Locomotives. December 1988: 120W PA Amplifier (With Balanced Inputs), Pt.1 ; Diesel Sound Generator; Car Antenna/ Demister Adaptor; SSB Adaptor For Shortwave Receivers; Electronics & Holden's New V6 Engine; Why Diesel Electrics Killed Off Steam; Index to Volume 1. January 1989: Line Filter For Computers; Ultrasonic Proximity Detector Use this handy form to order your back copies I --------- .------------------------ I I I Please send me a back issue for: I I □ I I □ May 1988 □ October 1 988 □ March 1 989 □ □ August 1 989 January 1990 June 1 990 □ June 1988 □ Nov_ ember 1 988 □ April 1 989 □ □ □ September 1989 February 1 990 July 1 990 □ February 1 988 □ July 1 988 □ December 1988 □ May 1989 □ October 1 989 □ March 1 990 □ August 1 990 □ March 1 988 □ August 1988 □ January 1 989 □ June 1 989 □ November 1989 □ April 1 990 Streel______________________ SILICON CHIP I I Detach and mail to: SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROY BEACH NSW 2097 OR FAX: (02) 979 6503 I I I I I I I I l I ------------------------------J- Suburb/town _ _ _ _ _ _ _ _ _ _ _ _ Postcode____ ~------- I I j L-1__.___.___._~I (PLEASE PRINT) 118 +--7I □ April 1 988 □ September □ February 1 989 □ July 1 989 □ December 1989 □ May 1990 Enclosed is my cheque/money order for $ ______ or please debit my D Bankcard D Visa Card D MasterCard Card No . I~~~~ ] I~~~~ Price: $A5.00 each (includes postage). Overseas orders add $A 1 .00 per issue for postage. Signature _____________ Card expiry date_ ~ - NZ & PNG orders are sent by air mail. Name _________________________ 1 L--'---'--'-~I I I ~ For Cars; Simple Computer Sound Repeater; 120W PA Amplifier (With Balanced Inputs) Pt.1; How To Service Car Cassette Players; Massive Diesel Electrics In The USA. February 1989: Transistor Beta Tester; Minstrel 2-30 Loudspeaker System; LED Flasher For Model Railways (uses LM3909); Build A Simple VHF FM Monitor (uses MC3362), Pt. 1 ; Lightning & Electronic Appliances; Using Comparators to Detect & Measure. March 1989: LED Message Board, Pt.1 ; 32-Band Graphic Equaliser , Pt.1 ; Stereo Compressor For CD Players; Map Reader For Trip Calculations; Amateur VHF FM Monitor, Pt.2 ; Signetics NE572 Compandor IC Data; Electronics For Everyone - Resistors. April 1989: Auxiliary Brake Light Flasher; Electronics For Everyone: What You Need to Know About Capacitors; Telephone Bell Monitor/ Transmitter; 32-Band Graphic Equaliser, Pt.2; LED Message Board, Pt.2. May 1989: Electronic Pools/Lotto Selector; Synthesised Tom-Tom ; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference; LED Message Board, Pt.3; Electronics for Everyone -' All About Electrolytic Capacitors. June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586); Passive Loop Antenna For AM Radios; Universal Temperature Controller; Understanding CRO Probes; LED Message Board , Pt.3 ; Coherent CW - A New Low Power Transmission Technique. July 1989: Exhaust Gas Monitor (Uses TGS812 Gas Sensor); Extension For The Touch-Lamp Dimmer; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; NSW 86 Class Electrics; Facts On The PhaxSwitch - Sharing Your Phone Line With A Fax Machine. August 1989: Build A Baby Tower AT Computer; Studio Series 20-Band Stereo Equaliser, Pt.1 ; Garbage Reminder - A 7 -day Programmable Timer; Introduction To Stepper Motors; GaAsFet Preamplifier For The 2-Metre Band. September 1989: 2-Chip Portable AM Stereo Radio , Pt.1; Alarm-Triggered Telephone Dialler; High Or Low Fluid Level Detector (uses LM1830N); Simple DTMF Encoder (uses Texas TMC5089); Studio Series 20-Band Stereo Equaliser, Pt.2; Auto-Zero Module for Audio Amplifiers (Uses LMC669); A Guide To Hard Disc Drives. October 1989: Introducing Remote Control; FM Radio Intercom For Motorbikes (Uses BA 1 404 And TDA7000) Pt.1; GaAsFet Preamplifier For Amateur TV; 1 Mb Printer Buffer; 2-Chip Portable AM Stereo Radio , Pt.2; Installing A Hard Disc In The PC; A Look At Australian Monorails. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY and Morse); Super Sensitive FM Bug; Build A Low Cost Analog Multimeter; FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disc Drive Formats & Options; The Pilbara Iron Ore Railways. December 1989: Digital Voice Board (Records Up To Four Separate Messages, Uses Texas TMS3477NL and 256K RAMs); UHF Remote Switch; Balanced Input & Output Stages; National Semiconductor LM831 Low Voltage Amplifier IC Data; Install A Clock Card In Your PC; Index to Volume 2. January 1990: Service Tips For Your VCR; Speeding Up Your PC; Phone Patch For Radio Amateurs; High Quality Sine/Square Oscillator; Active Antenna Kit; The Latest On High Definition TV; Speed Controller For Ceiling Fans; Designing UHF Transmitter Stages. Februa!}'----t 990: 16-Channel Mixing Desk; High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2; PC Program Calculates Great Circle Bearings. March 1990: 6/ 1 2V Charger For Sealed Lead-Acid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 1 6-Channel Mixing Desk, Pt .2; Using The UC3906 SLA Battery Charger IC; Digital Waveform Generation Using a PC; The Controls On A Model Aircraft. April 1990: Dual Tracking ±50V Power Supply; VOX With Delayed Audio; Relative Field Strength Meter; 16-Channel Mixing Desk, Pt.3; Simple Service Tips For Your Microwave Oven; Model Aircraft Aerodynamics; Active CW Filter For Weak Signal Reception. May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors; The Mazzie CW Transceiver; Waveform Generation Using A PC, Pt.3; 16-Channel Mixing Desk, Pt.4; What To Do When Your Computer Goes Bung, Pt.1 ; Electronic Load For Checking Power Supplies. June 1990: Multi-Sector Home Burglar Alarm; Low-Noise Universal Stereo Preamplifier; Load Protection Switch For Power Supplies; A Speed Alarm For Your Car; Design Factors For Model Aircraft; Fitting A Fax Card To Your Computer; What To Do When Your Computer Goes Bung, Pt.2. July 1990: Digital Sine/Square Generator, Pt.1 (Covers 0-5o"OkHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; Low-Cost Dual Power Supply; Inside A Coal Burning Power Station; Weather Fax Frequency List; What To Do When Your Computer Goes Bung, Pt.3; Digital Waveform Generation Using A Computer, Pt.4 (PC Board Plus Software). August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Appliances; Horace The Electronic Cricket; Digital Sine/Square Wave Generator, Pt.2; The Tube Vs . The Microchip (Two Shortwave Receivers Compared); What To Do When Your Computer Goes Bung, Pt.4. PLEASE NOTE: November 1987, December 1987 & January 1988 are now sold out. All subsequent issues are still available but stocks of February, March, April & June 1988 are low. Order now if you want these issues. SEPTEMBER1990 119 ASK SIUCON CHIP Got a technical problem? Can't understand a piece of jargon or some electronic principle? Drop us a line and we'll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097. Charging 24V batteries with the UC3906 In the March issue of SILICON CHIP, you discuss how the UC3906 battery charger IC can be used to charge up 6V and 12V sealed lead acid batteries. Can the IC be set up to charge 24V batteries and if so, how can this be done? (R. G., Chapel Hill, Qld). • It's quite easy to modify the circuit to charge up 24 volt batteries and you don't need to rewire the circuit. All you need to do is change four resistors, Ra to Rd. Ra now becomes 360k0, Rb becomes 33kn, Re 36k0 and Rd 560kn. These should be 1 % resistors since they determine the threshold voltages for the charger IC. The float voltage, Vf [the voltage the battery sits at when fully charged), now changes to 27.2 volts. The trickle voltage Vt [the voltage below which the battery is charged up at the trickle rate) is now 14.2 volts. You will need to increase the power supply voltage to about 35 volts to allow for the increase in battery voltage and make sure the series pass transistor (Ql} has adequate heatsinking. Not knowing the capacity of the battery you wish to charge up ,. we Ceramic filters for VHF Receiver I am building the Simple VHF FM Monitor Receiver [SILICON CHIP, March 1989} but am unable to get a 3-pin 455kHz filter to fit the board. All you can get here in NZ are 5-pin versions and these are too big to fit. Can you can help me find where to obtain a 3-pin type. (D. S., Dunedin, . NZ). • The 3-pin ceramic filters are now almost impossible to get but it is possible to substitute the 120 SILICON CHIP have chosen the original maximum value of 500mA. If this is too low, change the value of Rs to a suitable value by using the formula: Imax = 0.25V/Rs. If this current is to be more than 1 amp, you'll need to use the BD650 Darlington transistor as well, but this will all depend on the capacity of your battery. If you wish to reacharge a 24V truck battery, however, we cannot guarantee that this circuit will give you optimum results. It will work but because of the differences between sealed lead acid and normal automotive lead acid batteries, the results you get, and certainly the time taken to recharge them, may be quite different. Ignition killer is not a problem I'm writing in response to P. J.'s question in Ask SILICON CHIP in August about installing an ignition killer in his VC Commodore. I've got a VC Commodore with an ignition killer installed in it, and it has been there for some time now. It was from Dick Smith Electronics [Cat K-3255). I ran the wire to the killer circuit through the plastic tube that the wires from the coil to the electronic 5-pin types that you have found are available. Sure, they won't fit the board as it is but they can be adapted if you are prepared to drill a few more holes. Data and a table on the various 455kHz filters was published on page 93 of the December 1989 issue. This will show you how you can substitute the 5-pin types. By the way, Dick Smith Electronics produced a revamped version of this kit and it does use the 5-pin filter. This kit is available in New Zealand. ignition go through, then through the slit loom tubing with the rest of the car's wiring. That made it look like there is no extra wiring. (0. M., Liverpool, NSW). Orphan computer to be disowned I am the not so proud owner of an IBM JX, first brought out around 1984. Over the years it has served me well but just can't keep the pace any more. It has 512K of memory, DOS 3.2 and twin 3.5-inch disc drives. The problem is that it doesn't seem to work with the new software on the market. Whether it's because it requires a VGA monitor or 640K memory or anything else I don't know. I was wondering if it would be cheaper to buy an XT or AT motherboard and build it up or buy an XT or AT ready to go? Also, which do you suggest out of the two, XT or AT? Finally, if I do build up a motherboard, can I use the memory chips out of my JX and just buy an extra 128K of memory? [P. E., Melton, Vic). • Unfortunately, the IBM JX has been left behind by the software and you are probably right in considering the purchase of an XT or AT. We really can't advise you on whether you should buy a motherboard or a ready built computer. It depends on your financial situation. However, in your case, it may be better to buy a complete computer and to sell the other one. As to the question of an XT or AT, if you are finding the JX left behind by the software, then the same will apply to an XT. Unless you have fairly limited applications for a computer, an XT is probably not the one to choose. Go for an AT if you can afford it. It is doubtful whether you could use the memory chips from your JX in an XT or an AT. You would have to confirm that the memory chips in the XT or AT were identical, not only in type number but in access time, before you could do any substitutions. Autotransformer convention My thanks to Steve Payor for his clever tip in the June issue [Circuit Notebook) about reconfiguring a power transformer to give a 220 volt AC supply. It has made life easier for my computer monitor. However, I have always understood that the common connection of a step-down autotransformer should be on tlie neutral side. Should not this circuit be revised so that the output voltage is reduced with respect to earth, rather than by raising its neutral above earth? [D. M., Yorkeys Knob, Qld). • It is true that it is customary to wire a step-down autotransformer with the common connection on the neutral side [as shown in Fig.1). However, in this case, Steve Payor has connected the transformer so that the normal secondary winding will be connected to the neutral side and this will reduce the voltage stress on it. This is a good idea because, normally, a transformer has lower rated insulation for the secondary winding. In practice though, the insulation on modern transformers is so good that you could connect the circuit either way without problems. High energy ignition circuit change I want to build the high energy ignition circuit published in the May 1988 issue of SILICON CHIP. Have there been any alterations to the circuit since the time it was printed? (J. S., Preston, Vic). • We do have one recommended change. We suggest that the four 1N4761 75V 1W zener diodes be Increasing the gain of the bowtie array I would like to ask you if you can give me any information in regard to increasing the gain of the Bow Tie UHF Antenna (SILICON CHIP, January 1988), either by increasing the size or by stacking; if by stacking whether vertical or horizontal and how far apart and method of coupling etc. (R. G., Forster Keys, NSW). • Unfortunately, we have no information on increasing the gain of the bowtie array, either by increasing the size or by stacking. That is not to say you can't increase the gain by increasing the size but to do so would mean a complete re-design. You can also increase the gain of bow tie arrays by stacking. In both cases the gain will be increased by the same amount, but changed to 1N5374 75V 5W zeners. There have been a number of instances where the 1W zeners have failed when spark plug leads have been dislodged. Longer messages on Digital Voice Board Recently we purchased a Digital Voice Recorder board as featured in SILICON CHIP. The magazine article implies that the four individual 30 second recorded messages can be chained into one continuous two minute message. The printed matter we have with the kit does not mention any modifications or what needs to be done. How do you do it? (J. P., Shepparton, Vic). • The Digital Voice Recorder board can be chained to provide a continuous message from the four separate memories by closing Sl, S3, S5 and S7 of the DIP switch. This will set the board to playback all four memories in sequence. To record in each memory, press the memory catch switch when LED 1 is on and then the record button. As soon as the record LED extinguishes, the next memory will be if you horizontally stack, the horizontal acceptance angle will be reduced which can be handy in reducing ghost reception. Similarly, if you vertically stack, the vertical acceptance angle will be reduced which can be handy in reducing ghost reflections from aeroplanes (ie, aircraft flutter). The way to connect two stacked antennas is by means of equal length cables which, ideally, should be a multiple of half a wavelength long at the approved frequency of reception. That is about as much as most texts say on the subject but if you stack two high gain antennas [such as our UHF bow-tie array) close together, you won't get much increase in gain. They have to be several wavelengths apart if your are to achieve close to the theoretical increase in gain of 3dB (ie, a power gain of 2). accessed and by again pressing the record button recording can continue. Do this for each memory. When in playback, it will be one long message. Note that there will be a slight sound gap between memories. To fix this, disconnect diode D12 and connect it to pin 8 [the record pin of IC7) instead of pin 9 when recording and back to pin 9 when under playback, using a changeover (SPDT) switch. This will trigger record on each memory automatically in one switch position and automatic playback in the other.~ Bose Lifestyle Music System - from p.22 issue to know all the answers to that question. By that time we will have put a Bose Lifestyle Music System through a battery of tests, objective and subjective. In the meantime, do you want to know the price? It's a lot more than you may have considered paying for a system in the past; around $4600 for the basic system described here. We'll give you the full rundown next month. [.ffl SEPTEMBER1990 121 CEN Cash in your surplus gear. Advertise it here in Silicon Chip. amplifiers, TVs & videos. Open Sat. 1 0am-5pm; Sun. 12.30-5pm. 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or 726 1613 AH. ANTIQUE RADIO ANTIQUE RADIO RESTORATIONS. Your one-stop electronic repair shop. Specialising in restoring vintage radios including chassis rewiring, quality new parts, valves, valve sockets, speakers, transformers, cabinet restoration. Quality secondhand radio dials & parts for most brands & models. About 400 radios in stock for restoration & parts. Every restored wireless is covered by a 2-year warranty on parts & service . French polishing of timber cabinets available. Vintage car radios in valve & transistor types available for restoration. Repairs done on tape decks, FOR SALE WEATHER FAX programs for IBM XT/ATs * * * "RADFAX2" is a high resolution, shortwave weather fax, Morse & RTTY receiving program. Needs CGA, SSB HF radio & Radfax decoder. Also "RF2HERC", "RF2EGA" & "RF2VGA", same as RADFAX2 but suitable for Hercules, EGA & VGA _cards respectively . $35 . * * * "SATFAX" is a NOAA, Meteor & MEMORY EXPANSION 9x4MB -120ns 28.00 -1 OOns 29.50 - 80ns 31.00 - ?Ons 36.00 - 60ns 46.00 -100ns 97.00 - 80ns 99.00 - ?Ons 115.00 - 80ns 94.00 - ?Ons 99.00 - 80ns 550.00 DRAM/DIP 4164 41256 41464 4 x256 1MB -1 OOns - 80ns - 80ns - 80ns - 80ns 9 x256 9x1MB 8x1MBMAC 4167-33 2220.00 TOSHIBA LAPTOP T1 DOOSE 2MB 515.00 T1600 2MB 370.00 T31 OOe 2MB 370.00 T3i OOSX 2MB 370.00 T3200SX 2MB 370.00 T3200 3MB 615.00 T5100 2MB 370.00 T5200 2MB 370.00 COMPAQ 386 -20, 386-25, 386-20e 386-S, 386-33 680.00 4MB MODULES 780.00 4MB BOARDS PS 2 2MB 250.00 30/286,50 2MB 290.00 70E61,121 2MB 290.00 70A21 182.00 296.00 416 .00 448.00 495.00 504.00 544.00 645.00 825 no CYRIX 610.00 650.00 1210.00 WEITEK 990.00 1600.00 1720.00 387SX-16 387DX·20 387DX-33 2.50 2.80 2.90 9.85 9.85 Prices at July 28 INTEL CO-PROCESSORS 8087-2 80287-10 80C287-12 387SX-16 387DX-16 387SX-20 387DX-20 387DX-25 387DX-33 SIMM & SIP 3167-20 3167 -33 4167-25 Sales Tax 20%. Overnight delivery. Credit cards welcome. Suite 205/83 Longueville Road, Lane Cove 2066. PELHAM Q ► ..I D. D. ::, en w ICU ~ 0 0.. a. en -0 II.I IC .£ :::, o6 (D :E~ :5 0. ::C IC (.) !: ~ Cl) 122 '6, u 0 -... ·s ... C Cl) Cl) :0 ..5ll 0 u Q) -~ i:i:i fo6 > <( (/) Ol C Cl) 0 ~ a: ·;;; (D ....Cl) (/) ~ -0 0 (/) 0.. E 0 -~ 0 0 D.<( 0. 0. 0. :::, :::, -i( (/) -i( (/) SILICON CHIP (/) Cl) Ol 0 ..c 2.... C Ol "cii Cl) 0 -i( Q) 0 0 .0 ..5ll 3: 0 -~ ro 1i:i0 (/) Cl) £ 0. .... >, ....Cl) 0 0 ~ >, -0 ..... 0 -~.... E ~ Cl) Cl) (D (/) ai E 0. (/) (/) • Cl) 5, • Cl) • Cl) ► t- Cl) >- ;;:::, ;;:::, 0 .0 .'=2 't (/) > ..I C1l ro > t- .... 0 ~ .... ~ .... ....0. (.) = C1l :::, c x >< C1l ~a cii w w .r:. Cl) cii -~ -o ~o > ..c C1l Cl) (J)N 0 § >Cl) Cl) "C ·<( ~ II) - Cl) C: 0 - :::, II) Cl) ....Cl) .... -0 (',• (/) w~~ ro ow ·;::en a0,c Tel (02) 427 0011 Fax (02) 418 6831 /428 5460 Cl) .... u .... _a, z .... .... Q) ... ...._ o.., Cl)> .E Cl) IC in ..c C1l ......... (.) o. ·- (/) -0 -~ ~ Q.) C1l 0 . - 0.o_CI) ai 0 Cl).- C C .._:::, C Cl) . u O ·- II.I 'It 0 ..I w- t0 ~<p(/)Q) a. IC ~ ~~ Q = WHOOPS! MY 280-BASED PBUFF printer buffer just doubled its memory capacity again . Over 3000 kits now sold. Combinations of DIP/SIPP/SIMM DRAMs in 9 memory sizes up to 2Mb . Rev J board, Ver 4.3 EPROM and instructions $39. Cable board $9. P&P $3. Serial board and many other options available. Send a 43c stamp for a free catalog to: Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. KITS AVAILABLE FOR the ETI Digi125 $17 .95 plus $2.50 p&p . Heatsink not supplied. Kits built and repaired . Repairs to radio control toys. Model railway projects designed and built. Prototype and production board supplier to the hobbyist. Supplier of PCBs for projects in SILICON CHIP. Electronic Toy Services, 2/111 Glynville Drive, Hackham West, SA 51 63. Phone (08) 382 8919. BREAKOUT BOXES. Datacom Technologies, lifetime warranty. From simple BOB to LAN testers and data tool, multifunction tester. Range of products specially suited for the technician. Esckay Printernet (02) 891 1282 or (02) 369 27 48. D. 0. (/) 0 ~ GMS weather satellite picture receiving program. Uses EGA & VGA modes, needs EGA or VGA colour monitor & card, plus "WEATHER FAX" PC card. $45. * * * All programs are on 5.25-inch or 3.5-inch discs (state which) & include documentation. Add $3 postage. ONLY from M. Delahunty, 42 Villiers St, New Farm, Old 4005. Phone (07) 358 2785. I,..,. ,c JILOA (TECHNIKIT DIV.) ACTIVE SHORTWAVE ANTENNA (SILICON CHIP, Jan. 1990) . Complete kit $59; built & tested $119; case $10. LOOP ANTENNA. Improve signal strength & quality with this portable antenna. Kit $44; Fully built $69. PO Box 73, Glenhuntly, Vic. 3163. Phone(03)571 6303. IIT MATHS ,,"Is,-~ COPROCESSORS 2C-08 2C87-8MHz 2C-10 2C87-10MHz 2C-12 2C87-12MHz 2C-20 2C87-20MHz 2C-20H HYPERBOARD 3C-16 3C87-16MHz 3C-20 3C87-20MHz 3C-25 3C87-25MHz 3C-33 3C87-33MHz 'lr ,,o ~{~ 476 .S.s 528 618 645 130 890 915 1148 1380 CLASSIFIED ADVERTISING COUPON Advertising rates for this page: Classified ads - $7.00 for up to 15 words plus 40 cents for each additional word; Display ads (casual rate) - $20 per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. If you use a PO Box number, you must include your permanent address and phone number for our files. We cannot accept ads submitted without this information. To run your own classified ad, put or.e word on each of the lines below and send this form with your payment to: Silicon Chip Classifieds, PO Box 139, Collaroy Beach, NSW 2097. PLEASE PRINT EACH WORD SEPARATELY, IN BLOCK LETTERS 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ($7 00) 16 ($7.40) 17 ($7.80) 18 ($8 20) 19 ($860) 20 ($9 00) 21 ($9.40) 22 ($9.80) 23 ($10.20) 24 ($10.60) 25 ($11 00) 26 ($11.40) 27 ($11.80) 28 ($12 20) 29 ($12 60) 30 ($13.00) 31 ($13.40) 32 ($13.80) 33 (14.20) 34 ($14.60) 35 ($15.00) 36 ($15 .40) 37 ($15.80) 38 ($16.20) 39 ($16.60) 40 ($17.00) 41 ($17.40) 42 ($17.80) 43 ($18 20) 44 ($18.60) 45 ($19.00) 46 ($19.40) 47 ($19.80) 48 ($20.20) 49 ($20.60) 50 ($21.00) 51 ($21 .40) 52 ($21.80) 53 ($22.20) 54 ($22.60) 55 ($23.00) 56 ($23.40) 57 ($23.80) 58 ($24.20) 59 ($24.60) 60 ($25.00) FIVE YEAR WARRANTY CAD CONNECTION PHONE (02) 957 6719 FAX (02) 954 5550 MEMORY EXPANSION. Upgrade your PS2. Toshiba Laptop, Compaq, IBM Laser, HP Laser, PC compatibles and DEC equipment. You can choose from genJine or compatible chip equivalents. Ring today for an up-todate price list. Esckay Printernet (02) 891 1 282 or (02) 369 27 48. Don't delay. · UC3906 IC SOFTWARE: from the author of the SLA Battery Charger in SILICON CHIP, March 1990. Allows you to quickly design a charger for any SLA battery between 4V & 30V. Available on 5.25-inch 360K disc for IBM XT/ AT (GWBASIC required), C64/C16, Apple II (FPBASIC required) with instructions. $19.95 each (please specify computer) . Only from D. Yates, PO Box 134, French's Forest, NSW 2086. Name ........ ... ... ... ... ..... ............. ... ...... ... .. ..... .. . Street Postcode Suburb/Town Enclosed is my cheque or money order for$ ................ .. . . D Bankcard D Visa Card Signature .......... .......... , ...... . ROBOTICS: experimenter's kit. Includes IBM-PC controller, PSU, stepper motor, manual, software $99. Digital voice recorder TMS-334 7 chips $25. PROJECT PCBs: ETI-DIGI 125 audio amp $9/pair, ETl-1623 IBM PIA card $39. 95, 6502 / Z80 / 6809 miniprocessor $49. PRE-BUil T AUDIO AMPS: 3.5W LM380 $20, LM1875 $30, 150W .... or please debit my D MasterCard Card expiry date ..... ../ .. . FAX THIS COUPON WITH YOUR CREDIT CARD DETAILS TO (02) 979 6503 IC-150 $99, 300W IC-300 $179, 60W Valve-1 $99, 200W Valve-2 $199, Audio ToolkitTool-1 $69, FET-1 super quality stereo preamp $20, Bass & Treble $23. PC Computers, 36 Regent St, Kensington, SA. Phone (08) 332 6513. SMARTWORK POST-PROCESSOR: if you own a HP? 4 7 5 or compatible flat bed plotter you can plot your own PCBs direct on blank board ready to etch. PP plots 1: 1 and mirror image. Only $99. PC Computers (08) 332 6513. continued next page SEPTEMBER 1990 123· r?CF~EEPosT-su11scRIPTio~-co~;o~-----. To: Freepost 25, Silicon Chip Publications, PO Box 139 Collaroy Beach, NSW 2097, Australia. NO POST AGE ST AMP REQUIRED IN AUSTRALIA. □ New subscription Adroit Electronics ..... .. ... ... . 122 Altron ics ............. ..... ...... 68-7 3 Arista .... ...... ..... ... ..... .. .... .... 45 Back Issues ..... ....... ... 118,119 Board Solutions ........ 4 ,5,57,59 Start in _ _ _ _ _ _ __ [J Renewal Name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ (PLEASE PRINT) Street _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Bose Australia ..... .. ..... 104 ,105 Cad Connection ........ .. ...... 1 23 David Reid Electronics ...... IFC, 1 52, 53 Dick Sm ith Electronics ... .. 1 0 -1 5 Electronic Solutions .... .... 46,4 7 Elmeasco .. ..... ... .. ........... . OBC Suburb/town _ _ __ _ _ _ _ _ _ _ _ _ Postcode_ _ __ year ( 1 2 issues) □ $A42 Australia 2 years (2 4 issues) □ $A84 NZ & PNG (airmail) □ $A65 □ $A130 Overseas surface mail □ $A62 □ $A130 Overseas airmail □ $ A 1 20 □ $A240 Force Electronics ....... 110, 111 Geoff Wood Electronics ..... ... 23 Enclosed is my cheque/money order for $ _ _ _ _ or please debit my u U Visa Card Bankcard CardNo . l~ ~ ~ 0 MasterCard ~I ~I~~_] l~~~~I ~I~~~ Signature _ _ __ _ _ _ _ _ _ _ _ Card expiry date _ ~ - - Note: all readers who have a valid subscription as at 12th December, 1990 are automatically included in the draw for the Bose Lifestyle Music System (see pages 104-105). L __ ___ _ _ _ ___ _ _ _______ __ _ _____________ j DIGIT AL WAVEFORM GENERATION: as described in SILICON CHIP in March, May, June & July 1990 . PC board and software to generate waveforms. Both for only $39.95 including p&p. Instructions included. PC Board $16 .00, Software $32.50 including postage. Send cheque or money order to M. Radvanyi , PO Box 49 , Kingswood, NSW, 2750. FOUR ONLY MARCONI TF995A5 AM /FM signal generators. 200kHz to 220MHz in 5 ranges . 1 00mV1µ V. Clean with copy of service manual, $375 ea. TWO ON LY ST A TIC INVERTERS 48V DC input at 2A. Sinewave 1 % . Brand new , never used, Lynden PD 48-240-2RSA. Suit environmentalist. 1 9 -inch rack mount. Metered. $400 ea. FOUR ONLY HAND-HELD megger testers . Battery operated . Two units are BM7 -500 (tests insulation resistance to 1 00MQ at 5.00V DC); other two units are BM7-250 (50MQ at 250V DC) . Ideal for electricians and for testing tel.ephone safety . As new in leather cases , battery operated, complete with leads . $80 ea. 124 SILICON C HIP Advertising Index I I I I I I I 1 I TWO ONLY Y AESU YC-500S frequen cy counters. 1 0 Hz to 500MHz. Used, without manual , operational. $200 ea. TWO ONLY AVO AM/CW signal generators. Model CT- 3 78 . 2MHz to 225MHz . $ 150 ea. ONE ONLY A WA GAIN measuring attenuator. 80dB rang e, metered . Type No . 5AR8030 . $ 50 . ONE ONLY MARCONI UHF attenuator. DC to 1GHz; 0-1 4 0dB, 1 0dB & 1 dB steps. Type TF 21635. $300 . ONE ONLY HEWLETT PACKARD AM /CW signal generator. 10-4 50 MHz . ModelHP608C . $250 . Call fax or write to: AV-Com m Pty Ltd, PO Box 386 , Northbri dge 2063. Fax (02) 949 7095 . Phone (02) 949 7 41 7 (answering service) . WANTED W ANTED: ELECTRONICS Australia TV field strength meter. P Allford , Derby 7264. Phone (003) 5 4 2 138 . WANTED : HD6481 80 OR 2800 ch ip & RAM disk software for Mictrotrix system . 26 Bunburra St, Parra Hills West 5096 . Phone (08) 25 0 1869. Harbuch Electronics .... ... ...... 77 Hycal Instruments ...... ... ... .. 123 Jaycar Electronics .. .. ..... . 36 -39 86 -89 Jiloa .. .. ..... ........ ....... ... ..... . 122 J.V. Tuners ....... ......... ...... .. . 77 Kalex ....... .. ......... ... ........ .. 113 Oatley Electronics .. .. .. ..... .. .. 8 1 PC Marketplace .... .. .... ..... .. 1 03 Pelham ... ...... ........ ... ... .... .. 122 RCS Radio .... .. .. .... .. ..... ... ... . 7 8 Resurrection Radio ... ........ ... 65 Rod Irving Electronics .... 28,29, 96 ,97 , 114,115 Silicon Chip Binders .... ..... OBC Silicon Chip Subscriptions ... 79 Sound Australia .. ... .. .. .... .. ... 58 Subscriptions ... ....... ...... .. .. . 79 Tech-Fast ....... .... .... ... ..... .. . 63 Westinghouse . . . . .. .. . . . .. .. . .. 1 09 PC Boards Printed circuit boards for SILICON CHIP projects are made by: • Electronic Toy Services, 2/ 11 1 Glynville Drive, Hackham West, SA 5163 . Phone (08 ) 382 8919. • Jemal Products, 5 Forge St, Welshpool , WA 6106 . Phone (09) 350 5555. • Marday Services, PO Box 19-189, Avondale, Au ckland, NZ . Phone 88 5730. • RCS Radio Pty Ltd, 6!;i1 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491 . NO * High quality * Hold~ up to 14 * 80mm internal width * Gold printed with SILl€0N logo on spine and front cover CHIP . - " ~-~ ~ ~ These Beautifully mad binders will proteot );our copies of SILICON CHlP. We are especially pleased with their look and quality. As soon as the first batch came in, everybody on our staff wanted them to store their own personal issues. You will too. How~aO Phone (02!) 9 5644 Fax (02) 979 6503 ~ . -~· ~-- - Made with a distinctive two tofie green high-quality vinyl specially selected for SILICON CHIP, and with heavy board covers, each sinder holds a year's issues (the 14 issues of Vol. I or the 12 issues of Vol.2). ~ he-y will look really smart on your bookshelf. To oi:der your ·n in the coupon on page 124 and send it to SIUCON CIDP, PO B ollaroy Beacb, 2097. Alterrtaf ph (02) ?79 5644 e YiOur re4it c details, or fax lfO rde (02) 979 6503. , 1 .95 plus $A3 e for postage and p ng. postage and packing $A6). . .; CURSORS .unrr.a, o.: ·_.:- - ~osnwt1 ~", J J l ).JJ ~ip,.,,i .~ / ....,,,, CUUfll•L '!'!!I: - - . i.!~ • ~,~ ' 1fRll f.A ! 1,11)nf c;r1 C~2 en ca4 Aaa CIIZ lOMlll - - -. orcr 11v ewt ~ ~ ·, -..c"" - - """" .... !iiif • Al f - •. '. f,1(' 0: . ..::;;: CWl'L "Nli---r - - - - J.-CR12C A tw,f ------.. - SOllllU !"'""'I CH2o,D . VOLTS / DI V !!'!!I..: ~ l'il S H" ... 8 UlJ !!!!!!'t~ _ ..... o·· • '•lODf SV/FEP TIME / Of'/ ~ --: • Voltage Measurement • Time Measurement • Frequency Measurement The CS-6020 has CRT readout functions which provide digital indications of settings such as vertical-axis sensitivity and sweep time on the same screen as the observed waveform, as well as cursor functions which enable digital measurements such as voltage, time, frequency, and phase of displayed waveforms. This makes the CS-6020 a 150-MHz, 4-channel, oscilloscope 150MHz 4-Channel Oscilloscope with CRT readout, cursors, and trigger counting • .Voltage Ratio Measurement • Time Ratio Measuremen • c e usable by virtually anyone fo r waveform measurements and observation. It also has a wide range of advanced features such as Also new from trigger counting, cross-range Kenwood lOOWz variable, and B sweep variable, and virtually all functions are logic-controlled to ensure excellent reliability and flexibility. CS 6020 - i:5 : .' 'l<.SJ 100M z 4-Channel Osc illoscope CS-6010 ELMEASCO Instruments Ply.Ltd. N.S.W. (02) 736 2888 • Vic (03) 879 2322 • Old (07) 8751444 • S.A. (08) 344 9000 • W.A. (09) 470 1855 Silicon Chip Reader Survey Dear Reader, Please help us to help you. We want to make SILICON CHIP a better magazine but we can only do so if we know what your interests are . Please take the time to complete this survey and send it in to us as we value your opinion . By the way, you do not have to include your name and address unless you would like a personal response to a particular topic. We look forward to seeing your responses to the survey. Thank you for your support. Leo Simpson Publisher PERSONAL DETAILS First, we would like to know a little about you personally. These questions will help us classify our readers. As with the rest of this survey, your answers will remain strictly confidential. 1. Male or Female? (circle one) 2. Which age group do you fit into? (circle one) Under 18 18-24 25-29 30-34 35-39 40-49 50 and over 3 . Are you a regular or casual reader of SILICON CHIP? (circle one) Subscriber Regular 7 -1 2 issues per year 4-7 issues per year Casual Occasional Only when there are articles of interest 4 . How many other people regularly read your copy of SILICON CHIP? (circle one) None 1-2 3-5 5 or more 5. How much time do you spend reading each issue of SILICON CHIP? Less than 1 hour 1-2 hours More than 2 hours 6. How many times per month would you refer to SILICON CHIP for additional information? (circle one) 1-2 3-4 5 or more times OCCUPATIONAL DETAILS 7. Are you employed in the field of electronics? (circle one) Yes No 8. Which of the following best describes your type of work? (circle the ones applicable) Electronics Design Purchasing Officer Education of Others Electronics Research Component Purchasing Technical Sales Technician Retail Sales Serviceman Installation Other (please specify) ... . . .. . ....... . . . .... . . .. . ... . . ...... . . . . 9. Which of the following best describes your skill level in the field of electronics? (circle one) Engineer Technical Officer Serviceman Teacher Student Beginner Other (please specify) ... . . . .... . .. ..... . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . 10. Do you belong to a professional electronics organisation? (please specify) SILICON CHIP SUREY 1 11. On what basis are you employed? (circle one) Full time Part time Student Retired Other (please specify) .... . ..... . ....... .. .. . 12. What is your occupation classification? .... 13. Are you involved in purchasing electronic components or equipment during the course of your work? (circle one) Yes No 14. If so, which types? (circle the ones applicable) Passive Semiconductors Test equipment Computer products Microprocessor products Other (please specify) ........... . 15. What is your annual gross income? (circle one) Under $18,000 $25,001-$30,000 $18,000-$25,000 $30,001-$40,000 $40,001-$50,000 over $50,000 EDUCATION 1 6. What level of formal education have you attained? Primary school Technical College High School University Still studying (please specify) . . .. . . .. . . . . . 1 7. In which state do you live? . ........ . . . . 1 8. Which town or city? . . . . . . . . . . . . . . . . . . . . YOUR INTERESTS 19. In which of the following fields of electronics do you have an interest? (circle the ones applicable) Electronic Projects/Kits Video Systems Short Wave Listening/Scanning Automotive Electronics Personal Computers Hi-Fi Model Trains and Planes Amateur or CB Radio Communications Mainframes Other (please specify) 20 . Do you combine your interest in electronics with any other activities? (eg . photography) (please specify) 21. What would you estimate you have spent over the past six months on components in the following areas? Published projects $ Your own research $ .... . ... .. . . . . . . In the course of your daily work activities $ 22. Does advertising influence your buying of electronic equipment & components? (circle one) Yes No Sometimes Never 23. What type of electronic equipment do you presently own? (circle Hi-Fi RF Signal Generator Home Video Recorder Capacitance Meter Portable Transceiver Communications Equipment Digital Multimeter Amateur Station Including Transmitter Oscilloscope ShortWave Communications Receiver Other (please specify) 2 SILICON CHIP SUR VEY the ones applicable) Portable Video Recorder (With Camera) Frequency Meter/Counter Audio Oscillator Temperature Controlled Soldering Iron Computer Equipment 24. What types of electronic equipment do you plan to purchase over the next twelve months? (circle the ones applicable) Test Equipment Video Equipment Computer Equipment Radio Control Equipment Home Hi-Fi Equipment Amateur Radio Equipment Car Hi-Fi Equipment Automotive Equipment Vintage Radio Equipment Communications Equipment Other (please specify) 25 . How interested are you in construction projects for personal computers? (circle one) Very interested Occasionally Rarely 26. Are there any computer related articles you would like to see featured in SILICON CHIP. 27. Do you own a personal computer? (circle one) Yes No If not do you intend buying one in the next twelve months? (circle one) Yes No PLEASE ANSWER THE FOLLOWING IF YOU OWN A PERSONAL COMPUTER 28 . What is your equipment mostly used for? (circle the ones applicable) Home Business Research Education Other (please specify) . . . . ............ ...... .. . .. .. . . . ... . . . . . . . 29 . Which brand of computer do you own? 30 . Which operating system do you use? (e.g . MS-DOS, Apple etc.) (please specify) 31. How much have you invested in your computer (circle one) $3,001-$4,000 Under $1 , 500 $1,501-$2,500 $4,001-$5,000 $5,001-$7 ,000 $2,501-$3,000 system and related peripherals including other accessories? $7 ,001-$9,000 $9,000-$10,000 Over $10,000 32. Do you recommend to others what type of electronic equipment to purchase? (circle one) Yes No 33. If yes, what types of equipment? (circle the ones applicable) Hi-Fi Video Personal Computers Test equipment Communications Tools Other (please specify) ... .. .... . .... . . . ............ . .. . ... . . ....... . .... . .. .. .. ... . MAGAZINE INTERESTS 34. What other magazines do you read? (please specify) . . .. ... .. . 35 . Which areas of SILICON CHIP do you enjoy reading? (circle the ones applicable) Amateur Radio Articles For Beginners Ask Silicon Chip Circuit Notebook Computer Bits General Features Mailbag Market Centre Product Reviews Product Showcase Remote Control Serviceman Projects - (please specify which type, eg . test equipment) .. .. ... ... .. . ...... . SILICON CHIP SUREY 3