November 1991 - Silicon Chip Online

Outer Front Cover
Contents
Publisher's Letter: Wiring in older houses can be dangerous
Project: Battery Charger For Solar Panels by Steve Calder / Hycal Electronics
Order Form
Project: Build A Colour TV Pattern Generator, Pt.1 by John Clarke
Project: Flashing Alarm Light For Cars by Syd McKitrick
Project: Digital Altimeter For Gliders & Ultralights, Pt.3 by John Clarke
Serviceman's Log: A very circuitous exercise by The TV Serviceman
Feature: Amateur Radio by Garry Cratt, VK2YBX
Project: Build A Talking Voltmeter For Your PC, Pt.2 by Darren Yates
Feature: Computer Bits by Jennifer Bonnitcha
Project: Error Analyser For CD Players, Pt.3 by Stephen McBride
Vintage Radio: A simple junkbox 2-valve receiver by John Hill
Feature: The Story Of Electrical Energy; Pt.15 by Bryan Maher
Back Issues
Market Centre
Outer Back Cover

This is only a preview of the November 1991 issue of Silicon Chip.

You can view 46 of the 96 pages in the full issue, including the advertisments.

For full access, purchase the issue for $10.00 or subscribe for access to the latest issues.

Modifying The Way Windows Boots Up - E AUSTRALIA'S DYNAMIC - ELECTRONICS MAGAZINE~ * ColourTV Pattern Generator * Fit Your Car With A Flashing Alarm Light * Building The Digital Altimeter BATTERY SOLAR PANELS - Build this simple converter circuit & get the most out of your so,l ar cells TURNSTILE ANTENNA FOR WEATHER SATELLITE RECEPTION REGISTERED BY AUSTRALIA POST PUBLICATION NO NBP9047 Eight Advanced Features Make Metrix ASYC ®Series Safest Check these 8 important safety features only found in the Metrix ASYC Series • Advanced housing design has screw-free assembly and is waterproof through a patented low-pressure, double seal design. • Housing is moulded in VO-grade self-extinguishing material • VDE/GS certificated to international standards • Safe flexible test leads with shrouded plugs and large cross section conductors to reduce heating during high current measurements • Battery and fuse compartment are fully sealed, both internally and externally using a patented double seal design • Access to battery and fuse is only possible after removing test leads • SECUR 'X lead locking device prevents leads from being disconnected accidentally • Safety alarm gives an audible warning if measured signal exceeds specified range (1 0A ac or de, 750Vac, 1000Vdc) Quick Selection Guide Model MX20 MX50 MX51 MX51EX MX52 MX52S A multimeter doesn't just get used in the laboratory. It is a tool that is relied on to work accurately in difficult conditions - without endangering the user. ITT Instruments have analyzed the crucial elements in a multimeter and developed technical solutions for each of them. The result is ASYC®, Advanced Safety Concept, a synonym for safety and performance. It is your guarantee of safety and technological perfection. ----=-11 ■..::::.1.1.!.A ASYC <at> [Q] U Advanced Safety Concept BLMBASCO NEW SOUTH WALES Tel (02) 736 2888 VICTORIA Tel (03) 879 2322 QUEENSLAND Tel (07) 875 1444 Fax : (02) 736 3005 Fax : (03) 870 8972 Fax : (07) 277 3753 Basic Accuracy 0.5% 0.5% Bargraph Zoom Mode' Zero Mode 2 Live Trend Memory 3 Logic Function Min/Max Recording Store 5 readings Relative Mode RMS Conversion Frequency dB level High Accuracy(0.1 %) 4-20mA Intri nsic Safety EEx ib IIC T6 HBC fuse protection •• •• • • • 0.1 % •• • •• •• • • 0.1% •• •• •• •• •• • 0.1 % 0.1% • • •• ••• •• •• •• •• •• •• ••• •• • 1. Zoom mode gives 5x magml1cat1on 250 segment slidmg scale bargraph display 2. Zero mode functions as cen tre-zero meter for rapid polarity change measurements and zeroi ng 3. Live Trend mode digital display shows stored value, bargraph shows absol ute value (ie simultaneous display of current and stored values) Instruments Jlty.Ltd. SOUTH AUSTRALIA W. AUSTRALIA Tel : (08) 344 9000 Tel: (09) 470 1855 Fax: (08) 269 6411 Fax (09) 470 31 73 READER INFO NO. 22 VOLUME4 NUMBER 11 - - November 1991 FEATURES 6 An Ultrasonic Detector That Does Not False Alarm GET THE MOST out of your solar panels with this simple charger circuit. It features an automatic step-up/step-down converter circuit that ensures maximum efficiency. Details page B. New IC uses artificial intelligence & fuzzy logic 86 The Story Of Electrical Energy, Pt.15 by Bryan Maher Heavy electric vehicles in the mining industry PROJECTS TO BUILD 8 Battery Charger For Solar Panels by Steve Calder Get the most out of your solar cells with this simple circuit 16 Build A Colour TV Pattern Generator, Pt.1 by John Clarke Generates seven separate patterns, has RF & video outputs 24 Flashing Alarm Light For Cars by Syd McKitrick Fool car thieves with this simple, low-cost device 32 Digital Altimeter For Gliders & Ultralights, Pt.3 by John Clarke THIS COLOUR TV PATTERN generator produces seven separate patterns for TV set adjustments. It's easy to build & will prove invaluable for service work. See page 16. Final article has the construction & calibration details 60 Build A Talking Voltmeter For Your PC, Pt.2 by Darren Yates It talks & gives an on-screen readout 72 Error Analyser For CD Players, Pt.3 by Stephen McBride Building it & connecting it to your CD player SPECIAL COLUMNS 40 Serviceman's Log by the TV Serviceman A FLASHING alarm light may be all that is needed to deter a would-be thief from stealing your car. This effective unit switches on automatically as soon as you turn off the ignition. Turn to page 24. A very circuitous exercise 53 Amateur Radio by Garry Cratt file Build a turnstile antenna for weather satellite reception 66 Computer Bits by Jennifer Bonnitcha Modifying the Windows INI files tlclp oe111fonts. fon .. ugaoel!I. Fon Fonts .fon =ugasys .Fon display .dru•tpd19 .dru shell•uinfile.e)(e network.dru • COllll!l.dt"V '" COl!llll.dru sound .d/'U " SOUnd .dru A simple junkbox 2-valve receiver M use .dru • nouse .dru keyboal'd. dru- keyboai-d. llru DEPARTMENTS Publisher's Letter Mailbag Subscription Page Circuit Notebook Computer Update .Search 286grabber ,.ugacolor .gr2 386grabber • uga .gr3 Fiicedfon . fon .. ugafix. Fon language .dll • langeng .dll 78 Vintage Radio by John Hill 4 5 15 56 70 fdlt (boot] 84 Product Showcase 90 Back Issues 92 Ask Silicon Chip 94 Market Centre 96 Advertising Index systen. dru •ah1sys .df'U atf!l. system. dru • sys te111 . dru [keyboard] subtypetype•4 oemansi.bin keyboard . dll • THE WINDOWS INI files determine the way Windows boots up. On page 66, we show you how to edit these files to automatically load & run programs. NOVEMBER 1991 1 David Reid Electronics CITIZEN LCD Colour TV & Video Monitor CITIZEN ED7800 Digital Pocket Diary ■ ■ 32K 2.2" Screen Automatic tuning system ■ A/V Input Jack ■ Palm size Memory, Telephone Directory, Memo Reminder, Schedule Organizer, Calender, Home Time, Dally Alarm, World Tlme, Calculator, and More I ■ I orily $195.00 Now $199.00 AVS-30 Video Transmitter Portable P.A./Gultar Amp ■ only $89.95 Output: 10 watts ■ 12V DC/240V AC Operation ■ Volume, Bass, Treble Controls ■ 6.5" Speaker ■ Mlc. Input ■ Guitar Input ■ 240x285x155mm IJ only $149.00 PORTASOL PRO IRON KIT Butane Gas Power' d Kit Includes: ■ Soldering Tip ■ Blow Torch ■ Hot Blower ■ Hot Knife ■ FREE GAS 111 only $69.95 Home/Office SECURITY ALARM SYSTEM KIT Kit Contains: lx Alarm Panel ■ lx PIR Detector ■ lx Power Supply ■ lx Horn Speaker ■ 3x Reed Switches ■ lx Back-up Battery ■ only $349.00 Hand-Held POCKET TRANSLATOR ■ Instant word conversion of ENGLISH, FRENCH, GERMAN, SPANISH, ITALIAN. ■ 1,400 words In each language. Audio/Video Mixer AVM-3 ■ Ideal for the Video Camera Buff, who wish to dubb thler own narration and back~ground music to existing video tape recordings. only $169.00 APS305 Adjustable Bench Regulated Power Supply ■ ■ 0-30 volt DC o 0-5 amps Reverse polarity protection ■ Current limiting ■ Dual meters ■ Fully built Chassis Punch Set ■ ■ ■ Size: 16, 18, 20, 30mm Reamer: 3 to 12mm Made In Japan Now $49.95 ARLEc ■ ■ ■ ■ TX-60 TX-90 VX-60 VX-90 ■ MRX-60 ■ MRX-90 Normal Normal Chrome Chrome Metal Metal $2.45ea. $2.95ea. $3.50ea. $3.95ea. $6.99ea. $7.99ea. VOTED BEST TAPE What HiFi 7 AWARDS $22.00/10 $26.00/10 $32.00/10 $36.00/10 $62.00/10 $72.00/10 I VI I Remote Access Answering Machine ■ ■ ■ ■ ■ A-3000 Remote Control Unit ■ N.O./N .C. relay output up to 5 amps ■ 12 volt DC operated ■ Complete with two remote keys ■ 10 meter range ■ Control Just about anything I FUJI save $50.00 HSA4330 Weather ■ 30 watts RMS. 70Hz to 20KH 116xl20x186 ■ Mountln Included only $89.00 41 pee. Driver/Bit Set ■ ■ lpc. T-Bar driver handle 3pcs. Phillips Bits 4pcs. Slotted Bits 4pcs. Allen Bits ■ 2pcs. Square Bits ■ 6pcs. Torx Bits ■ 9pcs. Metric sockets ■ 9pcs. SAE sockets ■ lpc. 1/4" socke t adaptor ■ lpc. btt adaptor ■ lpc. 90deg. adaptor ■ Capacity: 2kg/ 4.5 pounds ■ Digital Read-out ■ Gram or ounce reading ■ Battery operated ■ ■ ■ PLUS only $19.95 FLUKE 79 SERIES II ■ Capacitance Frequency ■ Analog bar graph ■ 4,000 count display ■ Touch Hold ■ 0.3% basic acc. ■ Continuity beeper ■ 3 year warranty ■ Made MORE 111 only $59.95 AM/FM PLL TUNER ■ LED ■ FET Frequency readout FM front end ■ 20 statlon memory ■ Auto search tuning ■ Now only $199.00 Butane Pencil Torch PHONE/FAX SWITCH ■ Eliminates dedicated Fax lines ■ Fully automatic ■ Connecting leads supplied ■ Slim-Line d~slgn ■ 12 months warranty ■ The "Butane Pencil Torch" will melt solder, sliver solder, small brazing rod, glass tubing, and many other materlals. .. "'A~,, NICad volt o 500mAH In Japan ■ 1.2 ■ lx ■ lx A.C.N. 00hlf2-at2 Now $99.95 ■ only $9.95 ■ Freq. up to 20MHz ■ Sen. 5mV/DIV to l0V/DlV ■ Sweep: 0.5us/DIV to 50ms/DIV ■ Includes 2 x 1:1 10:l probes ■ 12 months warranty ■ 4• Screen ■ Dimensions: 212 x 133 x 336mm ■ 3x I and More I JIC-678N (LPG,LNG) Gas Leakage Detector CI-118A 20MHz 2 Channel Oscilloscope SuperTool $62.50 FM, SW, TV, Air, Marine ■ Remote Message Access Call Screening VOX Controlled Message Indicator 12 months warranty ■ Detects Propane, Butane and Methane gases. Inbuilt visual and audlable alarm. ■ N.O./N.C. output for alarm systems. ■ 12 volt DC operation. ■ Now $59.95 only $495.00 mllllng cutters wire brush grinding wh,el ■ 4x drill bits ■ 5x chuck collets ■ 6x eraser sticks ■ 10,000 RPM Drlil ■ Handy carry case ■ AM, $359.00 ,;:.~5- only $199.00 "'High Performance"' save $100.00 Ideal for watching a video In the kitchen, bedroom, etc. without having to move your complete VCR system or having long extension cables around the house. ■ Output Channel: UHF30 ■ l0mtr. Range ■ Power Supply lncl. RY-610 PRO SERIES Multiband Receiver That's Audio Tapes save $"40. 00 240 volt AC Mains Surge Protector ■ Protect your computer, HIFJ etc. against voltage surges. ■ Designed to substantJally reduce the possibility of damage to your equipment. ! ~; only $22.95 !~ i (--~\. ?/ "~ :JI < a.. -..-..:1:1.1 -"t;imoll.· PLUSCLC>CK ELECTRONIC ■ 12/24 hour dual timer/clock 2 count-down timers 2 pre-set memories ■ Count-up timer ■ Displays Hours, Minutes, Seconds. ■ Built-In alarms ■ ■ only $19.95 Your No. 1. electronics store 19 memory Hands-Free Telephone Computer Diskettes ■ ■ ■ ■ 5.25" 5.25" 3.5" 3.5" D.S.D.D. $4.70/10 D.S.H.D. $8.70/10 D.S.D.D. $8.95/10 D.S.H.D. $21.00/10 swltchable diallng 16 one-touch memories ■ 3 priority memories ■ Last number redial ■ Built-In two way speaker phone ■ 12 months warranty PS228 ARLEC 6 & 12 V Battery Charger ■ Charges 6 & l2 volt batteries Ht and Lo charge rate selector ■ Large ammeter ■ only $89.95 A vlatlon Head-Set ■ High performance, noise attenuating earphones. ■ Noise canelllng microphone ■ 011 fllled ear cushions ■ Standard aircraft jacks fitted ■ Short clrcult proof ■ 2 year warranty only $44.00 only $189.00 Cassette Tape Eraser ■ No battery or liquid required ■ Works on Pos/Neg Iron fields ■ Powerful and effective action ■ Simply pass the tape through .. the eraser a few times to erase tape Now $5.00 Portable CD Mount operated (9V 216) ■ Just the thing for cleaning keyboards, camera lenses, audio equipment, and more!! ■ Size: 115 x 38 mm (body only) approx. ■ Battery not Included temperature range: 400 & 600 C watts output High Air-flow rate ■ 12 months warranty ■ only $59.95 only $69.95 Car Alarm Warning Light "A Claytons Car Alarm " HAKKO ■ 12 volt operation flashing when Ignition Is off ■ Stops flashing when Ignition Is on ■ Simple connection ■ Temp. AdJ.: 200 - 480 deg. C ■ 24 volt&\ 50 watt element ■ Large range of tips available ■ Made Jn Japan only $13.95 only $199.00 ■ Starts The PDSl Portable Disc Shuttle with the new NAVCOM suspension system allows you to mount your DlscMan In your car and virtually eliminates skipping or mlstraklng. ■ Complete with swivel base, platform, brackets and aJI mounting hardware. ■ Made In U.S.A. only $49.95 CDA-4 CD Adaptor Switching Unit tool box ruler Allows you to connect your CD and another Au><. unit to one audio input In your amp. ■ RCA Inputs/output 10 volt AC o 1 amp Suitable for NetCom modems requiring a 9 volt AC supply ■ Also used for a host of other products ■ ~ only $19.95 "A very RARE product " MEGOHM Meter Kit ■ Check Insulation breakdown ■ 500V 1000V swltchable ■ Sult Electricians/Technicians ■ Complete kit only $79.00 only $23.95 ■ :J.2V DC to 240V AC Inverter Cont. power: 140Watts, 200W peak Protection: Overload, Undcr11oltagc, Overvoltage, Fused Input and output. ■ Low battery Indicator-Audio buzzer ■ 50x135x74mm ■ fnput via clg. lighter plug Output via 3 pin Aust. socket LED Indicators monitor IN/OUT volts. $9.90 $19.95 $36.95 $69.95 Be quick for this one I I ■ ■ Switch up to 4 pairs of stereo speakers Each speaker set can be Individually selected. ■ All four can be switched on at the same time. HDS90L Digital Probe type Multlmeter Watchman PRO Torch a only $35.95 ■ ■ 10.5-16 volt DC operation N.C. contact switch N.C. tamper switch ■ 84 deg. o 12M range ■ Walk test Indicator ■ a • FMA-10 Amp/J/Jed Indoor UHF/VHF/FM Antenna only $69.95 only $199.00 ■ Heavy Duty Aircraft aluminium ■ Brilliant Krypton globe ■ Adjustable focus ■ Uses 4 x D cells (not Included) 3 meters 5 meters 10 meters ■ 15dB amplifier (built-In) ■ 75 ohm coax and plug ■ 40-890 MHz ■ 240V AC supply ■ ■ ■ 1.8 meters ■ ■ ■ only $23.95 m y - p < > w ~ r 2C>C> ■ ■ SSS4 Four Way Speaker Switch ■ only ~ ■ 12 months warranty IBM Printer Cables Lim/led Stocks! Nylon Callpers Now $59.9S :i~t~l!a~~~ ranging ■ Volts AC/DC, Amps AC/DC, Logic, Ohms, Diode test, Buzzer. ■ Data Hold Now $54. 95 David Reid 127 York St. SYDNEY 2000 PH: (02) 267 1385 Electronics P.O. Box QI03, SYDNEY 2000 FAX: (02) 2618905 ~ ffiT --"'. SAME DAY MAILORDER DESPATCH* ~__.Ji Diners Club lntemat,onaf A.C.N. 001-372-372 926/50 DB-25 male to 36 centronlcs male Now $37.95 $4.95 10 volt AC Plug Pack ■ Flameless gas soldering Iron ■ High temperature pencil Harne torch ■ Hot knife ■ Hot blower ■ Wide flame torch ~CEHENT was $19.95 Now $9.95 Timing and Sensitivity adjustments Lights can be operated manually Ma><lmum 15 metre range Weatherproof housing 12 months warranty Soldering Station ■ ■ 150mm ■ Great for the ■ Better than a ■ ■ ■ ■ Vulcan 30 Soldering Kit ■ Mini-Vacuum Cleaner ■ Battery Night Watch PIR Flood Light Controller ■ Dual ■ ■ :ii~e.«:n:r~prroved Heat-Shrink Gun ■ 1600 ■ Tone/Pulse Be quick for this one I I ARLEc _., , Post ond Packing $5 - $25 ···•···· $4.00 $26 - sso ...... $6.00 $51 - $100 ...... $7.00 $101 - $499 .... $9.00 SSOO + ..... . ...... !· .6 . .· " ' FREE g·,~. '·~ '- Publisher & Editor-in-Chief teo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) PUBLISHER'S LETTER Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Darren Yates Reader Services Ann Jenkinson Sales & Marketing Mgr. Angela Clarke, B.A.(Comm.) Phone (02) 979 5644 Mobile phone (018) 28 5532 Regular Contributors Brendan Akhurst Jennifer .Sonnitcha, B.A. Garry Cratt, VK2YBX John Hill Jim Lawler, MTETIA Bryan Maher, M.E., B.Sc. Jim Yalden, VK2YGY Bob Young Photography Stuart Bryce Editorial Advisory Panel Philip Watson, MIREE, VK2ZPW Norman Marks Steve Payor, B.Sc., B.E. SILICON CHIP is published 12 times a year by Silicon Chip Publications Ply Ltd. A.C.N . 003 205 490. All material copyright ©. No part of this publication may be reproduced without prior written consent of the publisher. Printing: Magazine Printers Ply Ltd, Alexandria, NSW; Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $42 per year in Australia. For overseas rates, see 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 1a/77-79 Bassett Street, Mona Vale , NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. ISSN 1030-2662 4 SILICON CHIP Wiring in older houses can be dangerous This month , I want to talk about mains wiring in older homes , a subject that should be covered much more often in home renovation magazines but seldom is. It is a fact that the wiring in virtually all older homes is in a dangerous state. I am talking specifically about any Australian house built in the early 1950s or prior to that time. The wiring insulation in prewar houses was cotton covered vulcanised indiarubber or, during and just after WW II , double-sheathed tough rubber. Over the years, this rubber insulation at first perishes and then crumbles away at the slightest disturbance. Such wiring may operate without trouble for many years but the slightest disturbance, such as may be caused by a possum, rat or a person moving about in the roof area, dislodges the crumbly insulation and then you have a perfect recipe for a fire. A lot of fires in older homes start in the wiring for exactly this reason. Water is a big problem too. If the roof starts to leak or is damaged during a hailstorm (another common occurrence with older homes with their fragile tile or slate roofs), you can have the beginnings of a roof fire. The water runs down the wiring, seeps into the cracks in the insulation and the resulting leakage currents heat up the insulation until it begins to smoulder and then breaks into flame. I write from personal experience in this regard. What is the cure? A total rewiring job is the only solution. While you are at it, you will probably have to add in more power and lighting circuits and the power board with its worn out and corroded fuseholders will have to be replaced with circuit breakers. All told , it adds up to many thousands of dollars, a major cost which is rarely considered when such older homes are purchased. Was your home built around 40 years ago or prior to that? If so, you should get up in the roof and inspect the wiring. If it uses white PVC sheathing, then it is probably OK although it may still need upgrading to give more circuits, to allow earthed light fittings and more power ,points. But if the wiring uses black rubber insulation, you should start getting a few quotes from your friendly local electricians - have the job done soon because your home is at risk. · Leo Simpson MAILBAG Support for high-end class-A amplifier system In response to the letter from R. L. in Ask Silicon Chip for August 1991, referring to a sound system aimed at the "top end" of your readership, I for one am 100% in favour of the idea. It seems to me that home constructors fall into three categories: (1) The novice, who needs simple projects which have a good chance of success at first switch-on. (2) The budget conscious, who restricts projects to affordable levels and accepts the limitations of a design which is controlled by value for money parameters. (3) The more established and experienced builder who is able to commit to a long-term modular project such as R. L. The most important thing to this class ofreader is that the result be as good or better than anything else around - no excuses. The point I want to make is that there is a market out there that says to itself "if I can't build it, then what the hell, I'll just buy it". These people don't build to save money, but for the relaxation and the sense of personal achievement that goes with a highquality result. Peter Sherwood, Nerang, Qld. Variations to the remote control extender I recently built the Remote Control Extender as published in the October 1990 issue of SILICON CHIP. I did have some problems which I have solved with your assistance and I think it is possible other readers might be helped by my experience. My installation was fitted inside a chest of drawers. The IR detector is mounted immediately underneath the lip of the top of the chest. This offers good protection from physical damage. The leads were connected by two wires passed through two small holes drilled for the purpose and the total lead length was less than 100mm. Unfortunately, it did not work at first. The first question was what should be coming out of ICl, the SL486? The output from the two IR controllers I have is a series of pulses modulated at a much higher frequency. What was not expected was that the pulse envelope is not flat topped. Its amplitude has a small exponential decay. So guess what - the AGC of ICl with its fast attack time responded to the first l0µs pulse! I tried various methods of modifying the AGC behaviour including discharge resistance, plus larger and smaller capacitance, relative to the nominal 0.15µF. I eventually opted for a 22kQ resistor in series with the original 0.15µF. The actual capacitance was not particularly critical and neither was the series resistance; ie, I could make the combination work apparently as well with lµF. After this modification, the circuit worked with a range of about one metre. As I have previously mentioned, the leads to the IR detector were fed through the timber of the chest of drawers. I pulled them out and reconnected the detector, with it now poking out where the top drawer normally fits. The range was now up to two metres or thereabouts but not nearly good enough. I then tried shielding the leads from the IR detector. I used miniature shielded cable with two wires inside the common shield. The range was now in excess of 5 metres which was good enough for my purpose. Dale Rebgetz, Bayswater, Vic. Standard altimeters have better accuracy John Clarke's Digital Altimeter is intriguing although as a commercial pilot, I find it surprising that his experience with standard "sensitive" altimeters has been so poor (September, 1991). Even if he meant a 10% error and not a 10% "guaranteed accuracy", aviation is in big trouble. Two altimeters could err equally, but oppositely, enough to make the standard vertical separation of aircraft (1,000 feet) hopelessly unsafe. Two airplanes, supposedly so separated, could actually arrive at the scene of SILICON CHIP, PO Box 139, Collaroy Beach 2097. the same accident together. If the sensitive altimeter is so inaccurate, why did he use one as his own calibrating standard? One must also query the formula he gave for the standard atmospheric pressure curve, as it doesn't seem to add up. By the way, any such sensitive altimeter exhibiting "hysteresis" should be repaired or junked, and his complaint that they offer a pressure "offset" only up to about 2,000 feet is curious. If one is to take off from a runway that's, say, 7,200 feet above sea level , the altimeter would be set to 7,200, not to "zero" (which would be very poor airmanship ). The amount of offset provided is more than ample. George Lindley, SydneyNSW. Comment: the altimeters referred to in the article are of World War II vintage and as such, are not very accu rate. However these are the ones available at reasonable prices to enthusiast flyers. We are aware that commercial aircraft altimeters have much higher accuracy. Our reference unit had been calibrated recently and so was accurate enough for our purposes. The formula quoted in the article is incorrect. A correction appears in Pt.3. From our research, most flyers of ultralights, hang gliders, etc, do set their altimeters to read zero at ground level regardless of height above sea level and so the pressure offset facil ity is justified. Different display for the altimeter Wouldn't it have been better to have used the Farnell LS007CC display in the Digital Altimeter? This display has a "LO-BATT" icon included in the top-lefthand corner and could have been used instead of a separate position on the ON-OFF switch to indicate the LO-BATT condition. Mr O'Neill, Blackheath, NSW. Comment: we did consider the use of the Farnell LS007C display but the extra circuitry required to drive it would not fit onto the very restricted board space. NOVEMBER 1991 5 At last - an ultrasonic intrusion detector that does not false alarm A recent release from Fujitsu gives details of a MOS Application Specific Integrated Circuit (ASIC), the VF1010, which is currently under development for use in car intrusion detectors. Using artificial intelligence techniques, the new circuit should be able to reliably discriminate against false alarms. The VF1010 is the primary component of an ultrasonic detector system which it is claimed will eliminate all the problems that previously occurred in these systems, including false alarms. The detector consists of six components: the VF1010 integrated circuit, two transducers, one ceramic resonator and two ceramic capacitors. Block diagram Fig. i shows how it operates. The system continuously sends bursts of ultrasonic energy that effectively "photograph" the interior of the vehicle. The echoes are processed in the DSP portion of the IC by a expert system that discriminates between a true intrusion and natural phenomena. A combination of artificial intelligence and "fuzzy-logic" techniques in the VF1010 makes this possible. By comparison, most current ultrasonic alarms rely on frequency shift or Doppler techniques which have been shown to have shortcomings as far as false alarms are concerned. An algorithm in the VF1010 keeps track of any environmental disturbances, such as temperature gradients and changes in pressure and humidity, without compromising the sensitivity and reliability of the detectors. Included in the chip design is an ability to self-adjust to different vehicle sizes, shapes and materials. The circuit is also adaptable to the wide variety of transducers available PULSE OSCILLATOR MODULATOR DISCRIMINATOR CIRCUIT OSCILLATOR ENVELOPE DETECTOR A/D CONVERTER ALARM FIG.1 Ultrasonic Intrusion Detector VF1010 Competition Pulse Echo (Sonar) Mostly Doppler Effect <2mA >20mA ASIC + Two Sensors Resonator + Two Caps. >50 Tolerance For Sensors Wide Narrow Detects Sensor Blockage? Yes No None Thermal Gradients Vibration Unconditionally High Compromised To Limit False Alarms Yes No Approach Current Consumption Components False Alarm Conditions Sensitivity Self Adaptive* * Self-adjusts for different car models, sensor positions & sensitivites, & changing environmental conditions 6 SILICON CHIP and thus gives alarm manufacturers flexibility in this regard as well. It will work with all control modules with little or no modification. The detector interface to the module is a simple 2-wire connection (power supply and intrusion output). The detector system consumes less than 2 milliamps when in operation, meeting the new standards being set by the automotive industry. The main advantages of the new design are listed in the accompanying table. Discrete versions of the system have been tested in the field by the Ford Motor Company, Detroit, who are now committed to using the VF1010 in their 1994 model vehicles. Production versions of the VF1010 will be available in early 1992. Acknowledgement Our thanks to Peter Duddy of Pacific Microelectronics Pty Ltd, PO Box 2 7, Thornleigh, NSW for the information used in this article. SC BUILD YOUR OWN FAX/MODEM This is a fully featured kit Time saving The Comma Fax/Modem is a commercially designed kit you can build. It will turn your PC (or Macintosh) into both a fax machine which can transmit faxes up to 9600 baud, as well as a Modem which supports both 1200 and 2400 baud. The Comma Fax/Modem will also receive faxes in background while you continue to work. You get all the necessary components as well as a professional case, and power supply . You also receive FREE Fax/ Modem software. All this for less than $300. The Comma Fax/Modem uses the latest technology in digital signal processing to ensure lasting troublefree operation. Send faxes from home The Comma Fax/Modem is a fully featured fax machine similar to units costing over $1000, which will transmit faxes at up to 9600bp. Your faxes can now be sent directly from your PC without having to print them first. Programs supported such as Ventura Publisher, Wordperfect, Windows, TIFF and Dr Halo to name but a few. with all popular communication services including most bulletin boards. Available soon When faxing out the Fax/Modem will redial an engaged number so you can be sure your faxes are sent. The software also automatically keeps a corn plete log of both incoming and outgoing faxes. MMP and V42bis option. FREE Software With each kit you will receive the QL2 Fax/Modem software featuring both pull-down menus and mouse support. Also supported are cover pages, broadcast faxes, and scheduling. The software keeps a database type register of regularly used fax numbers for easy retrieval Value packed kit Each kit has been specially prepared to ensure you are able to build the Comma Fax/Modem with a minimum of specialised skills. We have also weighed each kit to ensure every component is included. As well it's also a modem The Comma Fax/Modem is a fully AT command series V compatible modem. Features include V22N22bis standards (V21/23 is an option) both 1200 and 2400 baud rates are supported as well as auto answer, dialing and disconnect. You will find it compatible There is also a step-by-step guide to testing your Fax/Modem throughout the building process. ONLY $299.00 You can view incoming faxes on-screen or print them using a standard dot matrix printer. Incoming files can also be exported in either TIFF or PCX format for use in most popular graphic packages. Only print the faxes you want to keep just think of the savings on expensive fax paper. Note: This device does not have an Austel permit in force. Connectjon to Telecom lines is an offence. Attention: Amstrad 2000 Owners · We have available a LIMITED quantity of external FDD, 1.44MB. Ideal for computer hackers. These drives have high quality Japanese Citizen Disk Drives. External case has a lead fitted with a Centronics 36 pin connector. Normally we would sell this unit for $329.00ea. This month only or until stocks are sold $99.00ea. Even as spare parts they are worth more than the asking price. DEALER ENQUIRIES WELCOME We also stock a range of motherboards, external disk drives, hard disk drives, addon interface cards, as well as a huge range of cables, adaptors, switch boxes and chips. Call today for very competitive pricing. ASK FOR A COPY OF OUR FREE CATALOGUE TRY PC MARKETPLACE SUPERFAST MAILORDER - PHONE OR FAX TODAY! Plii[ (jfeesons PC MARKETPLACE Pty Ltd FREIGHT CHARGES PHONE (02) 418 6711 FAX Include $10 with order for all normal items. Heavy items e.g. monitors add $15. 14 day money back guarantee. (02)4186713 Mail Order Address: P.O. Box 1100 Lane Cove NSW2066 e Order by phone (use credit card), by fax or by mail. Unless insurance Is declined tt will be charged al 1% of total purchase. This is for your protection. PRICES CURRENT FOR MONTH OF PUBLICATION OR WHILE STOCKS LAST SERVICE IS THE DIFFERENCE e SERVICE IS THE DIFFERENCE e ..= - -•- = j • • • • SERVICE IS THE DIFFERENCE • SERVICE IS THE DIFFERENCE Design by STEVE CALDER* Battery charger for solar panels Solar panels are coming into wider use every day but getting the most out of a panel is not simply a matter of hooking it directly across your battery. This step-up/step-down battery charger circuit does a much better job. The trouble with solar panels is that their output voltage and current varies widely depending on whether the sun is bright and high in the sky, or clouded over, setting in the west and so on. With the solar panel in bright sun, it may be able to deliver too much current for the battery while at times when the sun is low in the 8 SILICON CHIP sky, its output may be insufficient to charge a battery that badly needs it. What to do? The first approach may be to use a series regulator which at least will stop the battery from being overcharged but you then lose quite a lot of power in the regulator circuitry. Also, the point at which the solar panel stops charging comes quite a bit sooner because of the inevitable voltage loss across the regulator. Apart from those two drawbacks, a series regulator can do nothing about enabling the solar panel to charge the battery when its output is low. For this situation, you need a step-up circuit to increase the panel's output voltage. The circuit presented here does both step-up and step-down, according to whether the solar panel's output voltage is high (say above 15V) or low (below 12V), respectively. In practice, this charger circuit is connected between the solar panel and a 12V battery. It then ensures that the voltage across the battery does not rise above +14.3V, no matter how much the solar panel pumps out. \ The circuit The Solar Battery Charger is mounted on a small PC board which accommodates three transistors, a few diodes and one integrated circuit, ICl. This is the Motorola MC34063, a DCto-DC converter control chip. It is specially designed for this type of application. Its internal circuit diagram is shown in Fig.1. As you can see, its principal sections are a 1.25V reference, a comparator, an oscillator, some gating and a Darlington output transistor. Fig.2 shows a typical application circuit for the MC34063 in a stepdown converter circuit. In this circuit, the internal Darlington transistor is switched on and off at a high frequency set by the capacitor CT, connected to pin 3. The output voltage of the circuit is fed to a voltage divider consisting of 3.6kQ and 1.2kQ resistors and these set the nominal output voltage to 5V. The voltage divider connects to the inverting (-) input of the comparator. at pin 5 while the 1.25V reference is connected internally to the non-inverting (+) input. The operation of the circuit revolves around the comparator. If the output of the circuit is a little high, the inverting input of the comparator will be higher than 1.25V and so the internal Darlington transistor will be off. If The parts for the solar battery charger are all mounted on a PC board which in turn is mounted on an aluminium bracket. The unit enables you to get the most out of your solar panel by always charging the battery at the correct voltage. the output of the circuit is a little low, the inverting input of the comparator will be below 1.25V and so the internal Darlington will be on. The circuit will keep hunting between these two conditions and thereby maintain the output at close to the designated value. .Now let's have a look at the complete circuit of Fig.3. Switch Col lector Drive r r - - - 8 1 - - - - - - - - - - ~ Collector lpk 2 Sense lpk Oscillator Vee ICl drives two transistors, Ql and Q2, while a third transistor, Q3, is connected to the base of Ql. When the input from the solar panel is above 15V, the zener diode conducts and turns on Q3. This pulls down the base of Ql and prevents it from responding to any drive signal from ICl . In this mode, the circuit works as a Switch Emitter Cr 11220 µH 6 Timing Capacitor 1.25V Reference Regulator Comparator 5 Inverting O--+-----~ Input R1 4 1.2 k 3,6 k 470 + Vout 5.0 V/500 mA µF 'I'Co Gnd Fig.I: block diagram of the MC34063 DC-to-DC converter control IC. It includes a 1.25V reference, a comparator, an oscillator & a Darlington transistor. Fig.2: how the MC34063 is used in a step-down converter circuit. In this circuit, the internal Darlington transistor is switched on and off at a high frequency as set by capacitor CT, while Rt, R2 & the comparator set the nominal output voltage. NOVEMBER 1991 9 R1 O.Hl V+v---.----4p--.------.~5Mw~......- - - - - - + - - - - , 1k SOLAR 2200 PANEL 25VW + 2200 _ 25VW IC1 MC34063 + _ 2 6800 1.5M 100 + 16VW _ 470pF V-0--....__ _ _ _-+_ _ _ _....__ D2 MR851 1k 6.2k BATTERY _,.__ _ _....__~,___---4....,__ _.__ _ _ _ _ _ _.__.Q QJ BC547 E 10k B EOc VIEWED FROM BELOW SOLAR BATTERY CHARGER Fig.3: the final circuit uses ICl to drive two transistors, Ql & Q2. In the stepdown mode, Q3 turns Ql off & Q2 is switched at a 200kHz rate. In the step-up mode, both Ql & Q2 are switched simultaneously at a l00kHz rate & the energy in the inductor charges the lO0µF output capacitor via D1 & D2. step-down converter or, if you like, as a simple switching regulator. It works exactly like the circuit of Fig.Z, described above. There is one difference though and that involves transistor QZ. Whereas the circuit of Fig.Z uses no external transistor, the circuit of Fig.3 uses QZ to boost the output of the internal transistor. The transistor is switched on and off at about ZOOkHz, with the "on time" of the transistor being varied depending on the charge state of the battery and the output voltage from the solar panel. Step-up mode When the voltage from the solar panel falls below 15V, the operating mode of the Solar Battery Charger circuit changes quite markedly. Because the zener diode no longer conducts , Q3 turns off and this allows transistor Ql to respond to voltage signals from ICl. The chip is now in "step-up " mode whereby the voltage from the solar panel is boosted to a level which will continue to charge the battery. In this mode, both Ql and QZ are turned on simultaneously by ICl. This effectively places inductor Ll directly across the supply voltage from the solar panel. Ql and QZ stay on just long enough for the current through the inductor to build up to saturation, whereupon they both turn off simultaneously. The energy stored in the inductor is then fed to the lOOµF output capacitor via diodes Dl and DZ. So just how does the inductor deliver its stored energy via the two diodes? It is not easy to visualise but look at it this way. When a current flowing through an inductor is suddenly interrupted, the collapsing magnetic field around the inductor tends to maintain the current flow in the same direction. So what happens is that the current which previously was going through Ql is now diverted via Dl. Similarly, the current previously Where to buy the kit The Solar Battery Charger kit is available from Jaycar Electronics, PO Box 185, Concord, NSW 2137, or from any one of their retail outlets. Jaycar also have a selection of 12V solar panels and sealed lead acid batteries. Note: copyright of the PC board associated with this project is retained by Jaycar Electronics. * Hycal Electronics. Phone (02} 633 5477. 10 SILICON CHIP BCE passing through QZ is now diverted via DZ. So the energy stored in the inductor is discharged by means of a current pulse delivered to the lOOµF capacitor. Ql and QZ then turn on again and the cycle repeats itself, effectively stepping up the voltage from the solar panel. In this step-up mode, the transistors switch on and off at a lower frequency than QZ is switched in the step-down mode. Typically, in the step-down mode, the frequency of operation is around ZOOkHz but in the step-up mode it is around lOOkHz. Depending on the amount of voltage and current being delivered by the panel, the charger circuit may become audible due to a pulsed oscillation mode it can run in. The maximum output voltage of the charger circuit is set by the voltage divider resistors connected to pin 5 of ICl; ie, 6.ZkQ, 68kQ and 1.5MQ. By using the exact values specified and with the internal reference voltage of ICl exactly 1.Z5V, the output voltage is set at 14.3V. In practice, the internal reference voltage can vary between 1.18V and 1.3ZV: Also, the 6.ZkQ and 68kQ resistors are specified at 1 %, which means that the final battery voltage may vary between 13.3V and 15.3V for the worst case combinations of reference voltage and resistor tolerance. Typically, the final battery voltage should be close to 14V. If not, it is possible to tweak the circuit by chang- Fig.4: install the parts on the PC board exactly as shown here & note that Ql & Q2 are both oriented with their metal tabs facing outwards. The inductor (Ll) consists of 200 turns of0.4mm enamelled copper wire on a ferrite potcore. ing the value of the 1.5MQ resistor. To increase the final battery voltage, you can either increase the value of the 1.5MQ resistor or leave it out altogether. To reduce the final battery voltage, reduce the value of the 1.5MQ resistor, to say 1.2MQ or lMQ. The efficiency of the circuit can run as high as 85% although more typically it would run around 70%. Note that if the solar panel you are going to use with this charger circuit has a series protection diode (and most do), you can gain a further improvement in efficiency by shunting the diode. This is possible because diode Dl in the charge circuit effectively stops the battery from discharging via the panfll. As presented, the charger circuit will handle currents ofup to around 2 amps or so, making it suitable for use with solar panels of up to around 25 watts. Construction The charger circuit is built onto a small PC board measuring 75 x 50mm (see Fig.4). The two transistors , Ql and Q2, should be mounted on a small heatsink which can also double as a mounting plate for the board. The assembly process is quite simple and should take less than an hour, including winding the coil. Let's discuss winding the coil. It is quite straightforward and only requires one winding to be placed on the plastic former. Wind on 200 turns of 0.4mm enamelled copper wire and terminate both start and finish at the same point on the bobbin. This done, assemble the bobbin and the two ferrite core halves and secure them with electrical tape. The assembled transformer can then be affixed to the board using contact or epoxy adhesive. The wire ends can be stripped of enamel and soldered to their respective points on the board. The remaining components can PARTS LIST 1 PC board, 75 x 50mm 2 Philips 18/11-3B7 ferrite potcores (4322 020 21500) 1 single section bobbin for above (4322 021 30270) 1 right-angle aluminium heatsink bracket 2 T0-220 mounting hardware sets 4 9mm tapped PC standoffs MICA INSULATING WASHER ~,jl SCREW r ftllllill(3 -.__CASE 1 T0220 DEVICE Fig.5: transistors Ql & Q2 must be isolated from the metal bracket using mica washers & insulating bushes. After mounting each transistor, use your multimeter to confirm that its tab is correctly isolated. now be mounted on the board, taking due care with polarity of transistors, diodes and electrolytic capacitors. Note that diodes Dl and D2 need to be mounted "end on" and the leads of transistors Ql and Q2 should be left at full length to allow them to be suitably bent and then mounted to the heatsink panel. Do not make a mistake by inadvertently swapping Ql and Q2 otherwise the circuit won't work and you will probably damage both transistors. When mounting the transistors on the heatsinks, you will need a mica washer and insulating washer for both. Smear a little heatsink compound on the mounting tab and the heatsink mating area. Fig.5 shows the mounting details. You will need four leads terminated to the board, two for the battery and two for the solar panel. The negative leads from the battery and from the panel can both be black while the positive lead to the battery can be red and the positive lead from the panel can be, say, blue or orange. When all the assembly work is finished, check your work carefully Semiconductors 1 MC34063 DC-to-DC converter controller (IC1) 1 BO649, TIP121 Darlington NPN transistor (01) 1 BO650, TIP126 Darlington PNP transistor (02) 1 BC547 NPN transistor (03) 2 MR851 fast recovery diodes (01 ,02) 1 15V 1W zener diode (ZD1) Capacitors 2 2200µF 25VW electrolytic 1 100µF 16VW electrolytic 1 470pF ceramic Resistors (0.25W, 5%) 1 1.5MQ 1 6.2kQ 1% 1 68kQ 1% 2 1kQ 1 10kQ 1 6800 1 0.1 Q 5W wirewound Miscellaneous 2 metres of 0.4mm enamelled copperwire, insulated hookup wire, heatsink compound, screws, nuts, lockwashers, solder. against the wiring diagram and the circuit. To test the unit, you need a power supply capable of at least 18V DC or thereabouts, a lkQ 1 watt resistor and your multimeter. Connect the lkQ resistor to where the battery would normally be terminated and then connect the solar panel inputs to your power supply. Vary the output of the power supply between +lOV and +18V and check that the output voltage across the lkQ test resistor is constant and close to+ 14.3V. If the voltage is too high, say about +14.7V, you will need to reduce the value of the 1.5MQ resistor. Alternatively, if the output voltage is less than +14 V, you will need to increase the value of the 1.5MQ resistor or omit it altogether. SC NOVEMBER 1991 11 n:;::t~::::! l ' !R O f E S S I ON A L Fits In The Pocket! Butane Soldering Iron The totally portable, butane powered soldering iron. • Provides up to 60 minutes continuous use at full power (equivalent to 60 watts) • Temperature control from 10 to 60 watts Cat T-1370 s39ss - ~ Spare tips for T-1370: ~ ; ; ;: : : ::~~~~ 1.0mm tip Cat T-1372 2.4mm tip CatT-1369 3.2mm tip Cat T-1371 4.8mm tip Cat T-1373 Hot Knife Cat T-1368 s1595ea Gas Powered! The Professional 'Pocket' Soldering System • Pocket sized temperature adjustable Iron (up to 400 ° C) • 4 tips including hot knife & blow torch • Heavy duty case with clip on iron stand • Butane powered- refills in seconds Cat T-1374 { pa,tasnt [1 s7 4ss Scope Soldering Station S scope The versatile Scope ECT60L is every hobbyist's dream and every technician's essential tool! • Fully adjustable temp . (200-470 ° ) • Illuminated temp. readout • Monitors actual tip temperature • Rated at 60 watts CatT-1000 Spare tips for ECT60L: 0.8mm tip Cat T-1002 1.2mm tip Cat T-1008 1.6mmtip CatT-1004 3.2mm tip Cat T-1006 s259 Scope 20W Mains Powered 150 Watt Superscope Select the temperature you want and the Superscope will deliver it from cold in just 6 seconds! • Uses a non-corrosive stainless steel barrel for longer life • With spare tip and element • Requires a 3.3V <at> 30A transformer Cat T-1692 CatT-1605 • Lightweight air cooled finger grip • Earthed tip and grip for added safety • Designed for continuous use at 270 ° Cat T-1620 '6495 Spare Tips: Pointed 4mm flat 2mm flat 3mm S/ 0 ;;rz;,~ 3.3V <at>30A Transformer Cat T-1621 Cat T-1623 Cat T-1625 Cat T-1627 10-70 Watt Miniscope Lightweight, fingertip control gives precise temperature adjustment. Comes with a spare tip & element and requires 3.3V <at> 30A transformer Cat T- 1692. CatT-1660 A low voltage transformer for Scope soldering irons. Includes an electronic shield for extra protection. Suits T- 1605 and T-1660 Irons. Cat T-1692 s7995 s7495 =- ----,, Replacement tip packs Cat T-1601 / 3 5 1095111 DS XPRESS PHONE & MAILORDER SERVICE Outside Sydney (FREE Call) 008 22 6610 Sydney And Enquiries - 888 2105 FAX: (02) 805 1986 or write to OS XPRESS , PO BOX 321 N/ RYDE NSW 2113 All Major Credit Cards Accepted . 0 / Nite Courier Available. 24 HOUR DESPATCH OF ALL ORDERS PHONES SECURITY AUDIO COMPUTERS NSW • Albury 21 8399 • Bankstown Square 707 4888 • Blacktown 671 7722 • Brookvale 905 0441 • Bondi 387 1444 • Campbelltown 27 2199 • Chatswood Chase 411 ·1955 • Chullora 642 8922 • Gore Hill 439 5311 • Gosford 25 0235 • Hornsby 477 6633 • Hurstville 580 8622 • Kotara,.56 2092 • Liverpool 600 9888 • Maitland 33 7866 • Miranda 525 2722 • Newcastle 611896 • North Ryde 878 3855 • Parramatta 689 2188 • Penrith 32 3400 • Railway Square 211 3777 • Sydney City 267 9111 • Tamworth 6l 1711 • Wollongong 28 3800 ACT• Belconnen (06) 253 1785 • Fyshwick 80 4944 VIC • Ballarat 31 5433 • Bendigo 43 0388 • Box Hill 890 0699 • Coburg 383 4455 • Dandenong 794 9377 • East Brighton 592 2366 • Essendon 379 7444 • Footscray 689 2055 • Frankston 783 9144 • Geelong 232 711 • Melbourne City 399 Elizabeth St 326 6088 & 246 Bourke St 639 0396 • Richmond 428 1614 • Ringwood 879 5338 • Springvale 547 0522 QLD • 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 • Townsville 72 5722 • Underwood 341 0844 •SA• Adelaide City 223 4122 • Beverley 347 1900 • Elizabeth 255 6099 • Enfield 260 6088 • St. Marys 277 8977 WA• Cannington 451 8666 • Fremantle 335 9733 • Perth City 481 3261 • Midland 250 1460 • North bridge 328 6944 TAS • Hobart 31 08()0 NT • Stuart Park 81 1977 YOUR EIGHT SPECIALTY STORES IN ONE 81135/ PB Refine Your Reception QQ Coming Soon QQ ANTENNA TUNER AND RF PREAMP TV COLOUR PATTERN GENERATOR Improve the performance of your old shortwave receiver with this easy to build unit. Combining an antenna tuner with a RF preamp and preselector it's ideal for improving both sensitivity and selectivity in old receivers. The unit is powered by an external 12V _pg source (plug pack not included). - · ·--r · Includes all components, hardware, pre- punched silk Tune your TV to perform like new again! Generating seven separate patterns, it's the professional way to adjust your picture and track down faulty circuitry. It's easy to construct and requires only a small amount of wiring. Ideal for video enthusiasts, TV servicemen, hobbyist etc. Comes with all components, hardware, case and prepunched silk screen front panel. Includes plug-pack. ~~r;;;e~~~~~;~~lefnd preCat K-6100 <at>NOV'91 $109 ";t'; ·. ;,::~ Cat K-7355 i ,·: . _______ -- ·,. = J t Er ,,,,,,,,,.,, ····-...__~ fYfii114R NOV '91 s119 The Safe Solution QQ MAGNETIC FIELD STRENGTH METER Minimise the health risk of magnetic radiation with this handy meter. This accurate meter with LCD readout lets you measure the level of magnetic radiation emitted from appliances in the home & work-place. By changing your room layout, you can then minimises your exposure. Comes with deluxe case, all components, hardware and pre-punched silk screen front panel. Requires a 9V battery. Cat K-7600 Easy & Effective Q 084 MK.2 CAR ALARM A simple but effective car alarm. It features an ingenious voltage sensing trigger ci rcu it, which minimises wiring. Includes both entry and exit delays, flashing warning LED, automatic reset - and best of all, it's easy to construct and install. Includes all components, hardware and case. Supplied with IC sockets. $8995 Cat K-4310 So real... it's alarming! Q s329s FLASHING DETERRENT LIGHT Car thieves think twice when they see this red flashing light. Professional in appearance it's bright enough to be seen during the day. Because it's activated by the ignition you never have to worry about switching it off. It's also designed to withstand voltage extremes and the high temperatures of a car dashboard. Includes all components, mounting hardware, deluxe bezel case and bulb. ~ J!l!i!J~ <at> S99 S .t-----------------------------111 cat K-4200 J!};JJ NOV '91 MAJOR DICK SMITH ELECTRONICS AUTHORISED STOCKISTS: NSW: ARMIDALE: New England Electronics 711655 BALLINA: Ballina Electronics 867022 BEGA: OZTECH Electronics 923933 BOWRAL: F.R.H. Electrical 611000 BROKEN HILL: Hobbies & Electronics 884098 COOTAMUNDRA: Cootamundra Music & Ute 422561 COFFS HARBOUR: Coffs Harbour Electronics 525684 DENILIQUIN: Deni Electronics 813672 DUBBO: Chris's Hi R 828711 FORSTER: Forster Villar Electronics 545006 ~~i~: ~m maile~n!Jtm3:nw~Rt:1:~:~i:~"1,~Ll~::i~~L~l~reva:tt~ LITHGOW: Douroy Photographies 513173 LISMORE: Decro Electronic Services 214137 MOR~E: Moree Electronics 522091 MUDGEE: Headware 723895 MURWILLUMBAH: Strings & Things 723684 NARRABRI: Namoi Computer Service 923274 NELSON BAY: Nelson Bay Elect & Hobbies 813685 NOWRA: Nowra Electronics 210722 PARKES: Strad Music Cir 623366 PORT MACQUARIE: Hastngs Computer Ser.;ce 834574 RICHMOND: Silicon Crafts 784101 TAREE: Brads Electronics 526603 WAGGA WAGGA: Phillips Electronics 216558 WELLINGTON: Wellington Ser.;ce 452325 WINOOR: Silicon Crafts 776722 YAS3: Warmington Electrical 261116 YOUNG: Keith Donges Electronics 821279 VIC: BAIRNSDALE: LH & LM Crawford 525677COLAC: Colac Electronics312847MILDURA: Pullman Auto 0 29 ~~t~JN~Hfr::t~ i1e~~~~s G~XfM'w;.wi:M~~'lf? Services 627417 ~ : AYR: Delta Electrix 831566 BUNDAB~G: Bob Elkin Electronics 521785 CALOUNDRA: Electro-man 918533 DYSART: Dysart Videotronixs 582107 INGHAM: Masons Electronics 763188 INNISFAIL: lnnisfail Hi-R 612014 MACKAY: Stevens Electronics 511723 MARYBOROUGH: Keller Electronics 214559 NAMBOUR: Nambour Electronics Shop 411604 PIALBA: Keller Electronics 283749 STANTHORPE Granite Belt Communications 813333 TAS: BURNIE: Electronic City 314760 DEVONPORT: Al Electronics 248322 SA: MT GAMBIER: Hutchesson's Communicaton Cir 250400 PoRT LINCOLN: Basshams TV & Comp World 822788 WHYALLA: Eyre Electronics 454764 WA: ALBANY: Micro Electronics 412077 BUNBURY: Micro Electronics ·216222GERALDTON: Batavia Lighting & Electrical 211278 KALGOORLIE: Today's Electronics 215212 KARRATHA: Daves Oscitronic 854836 MANDRAH: Micro Electronics 5812206 PORT HEDLAND: Ivan Tomek the Elect 732"11 1~~~2rJ~~~ Ne~~~~~~~~ i ~i°~ OCT'91 Sing like a star! It's easy-to-build and doesn 't require special Karaoke tapes or CD's. By using the principles employed by recording studios, it allows you to rep lace the vocals on any of your favourite tapes or CD's with your own. Includes 'gain' and 'null' controls for sensitivity and signal balance. Comes in full form with all components (including IC socket), hardware and pre-punched silk screen front panel. Cat K-5300 s3~s -<at> NOV'91 Please contact your local store for availabil ity. B1213/M4 • ll111t~ SOLAREX SA-5 AMORPHOUS SILICON MODULE An encapsulated, module designed pri marily for use in systems with a 12 vo lt battery. In full sun light it will produce 300mA of current at a typical charging rate. Typical appli,.;ations include electric fences, infrared sensors and signals, maintaining the charge on marine and vehicle batteries, powering 12V DC devices, etc. 5 year lim ited warranty. THE SOLAR SOLUTION! MSX-18L MSX-40 FRAMED Specifications (all Specifications (all <at>25 °C) <at> Specifications (<at> 25 °C) - Size: Peak Watts: Current<at> Norn. Volt.: Volts (open circuit): Amp Hrs/week: (42hrs peak sun) Watt Hrs/week: (42 hrs peak sun) Size: Cat 0-1018 306mm x 346mm x 21mm Peak Watts: 5 watts Current <at> Norn. Volt.: 0.33 amps Vo lts (open circuit): 23 volts Amp Hrs/week: 13.86 (42hrs peak sun) Watt Hrs/week : 194.04 (42 hrs peak sun) Cat 0-1005 MSX-LITE SERIES Lig htweight, rugged, and extremely versatile .. . the MEGA series of photovoltaic cells are ideal for boating applications, bringing power to a campsites or your RV, mobile communications and more. Because they're lightweight and rugged, modules can be mounted easi ly on most surfaces. They come with a one year limited wa rranty and can be used individually or may be interconnected to provide in creased current or voltage. Specifications (all <at> Size: Peak Watts: Current <at> Norn. Volt.: Volts (open circuit): Amp Hrs/week: (42hrs peak sun) Watt Hrs/week: (42 hrs peak sun) Cat 0-1010 25 °C) 444mm x 267mm 10 watts 0.59A 21V 24.78A 346.92W 664.44W $279 MSX SERIES MODULES A superb series of MEGA modules which come framed with sturdy anodized extruded aluminium provid ing strength, durabi lity and ease of mounting. The panels are exceptionally well constructed, They have a dual voltage capability whereby the cells are electrically configured as two series strings. The strings may be placed in series or parallel providing 6V or 12V nominal output by moving leads in the junction box on the back of the panels. They're ideally suited to a huge range of applications including communications, pumping, irrigation and navigation .... all but the smallest of systems. MSX-18 FRAMED Specifications (all MXS-10L 25 °C) 444mm x 459mm 18.5 watts 1.13A 21V 47.46A <at> 25 °C) Size: 421mm x 502mm x54mm Peak Watts: 18.5 watts Current<at> Norn. Volt.: 1.13A Volts (open circuit): 21V Amp Hrs/week: 47.46A (42hrs peak sun) Watt Hrs/week: 664.44W (42 hrs peak sun) 5 year limited warranty Cat 0-1019 NSW • Albury 21 8399 • Bankstown Square 707 4888 • Blacktown 671 7722 • Brookvale 905 0441 • Bondi 3871444 • Campbelltown 27 2199 • Chatswood Chase4111955 • Chullora 642 8922 • Gore Hill 439 5311 • Gosford 25 0235 • Hornsby 477 6633 • Hurstville 580 8622 • Kotara 56 2092 • Liverpool 600 9888 • Maitland 33 7866 • Miranda 525 2722 • Newcastle 61 1896 • North Ryde 878 3855 • Parramatta 689 2188 • Penrith 32 3400 • Railway Square 211 3777 • Sydney City 267 9111 • Tamworth 661711 • Wollongong 28 3800 ACT• Belconnen (06) 2531785 • Fyshwick 80 4944 VIC • Ballarat 31 5433 • Bendigo 43 0388 • Box Hill 890 0699 • Coburg 383 4455 • Dandenong 794 9377 • East Brighton 592 2366 • Essendon 379 7444 • Footscray 689 2055 • Frankston 783 9144 • Geelong 232 711 • Melbourne City 399 Elizabeth St 326 6088 & 246 Bourke St 639 0396 • Richmond 4281614 • Ringwood 879 5338 • Springvale 547 0522 QLD • 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 • Townsville 72 5722 • Underwood 341 0844 •SA• Adelaide City 223 4122 • Beverley 347 1900 • 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 ORDER BY PHONE OUTSIDE SYDNEY (008) 226610 FREE CALL - SYDNEY AREA 888 2105 $279 Size: 764mm x 502mm x54mm Peak Watts: 40 watts Current<at> Norn. Volt.: 2.51A Volts (open circuit) : 21.1V Amp Hrs/week: 105.4A (42hrs peak sun) Watt Hrs/week : 1475.9W (42 hrs peak sun) 10 year limited warranty Cat 0-1040 MSX-60 FRAMED Specifications (all <at> 25 °C) Size: 1109mm x 502mm x54mm Peak Watts: 60 watts Current<at> Norn. Volt.: 3.76A Volts (open circuit): 21.1V Amp Hrs/week: 157.9A (42hrs peak sun) Watt Hrs/week: 221.9W (42 hrs peak sun) 10 year limited warranty Cat 0-1060 $599 * Amp Hour ratings are based on a daily average insolation of 600mW hr/cm 2 * Amp Hours and Watt Hours per week are based on power available from the module. VOLTAGE REGULATOR SRS-12 A high quality regulator designed especially for use with Solarex solar panels. It will maintain batteries in a high state of charge and also afford adequate protection against overcharging. Rated 12 volts <at> 8 amps. CatO-1100 B1135/M1 ____,,- ORDER FORM USE THIS FORM FOR ALL YOUR SILICON CHIP PURCHASES SILICON CHIP BINDERS: Yes! Please rush me_ _ _ SILICON CHIP binder(s)<at> $A14.95 each including postage. (Overseas orders please addA$3.00 each for postage). Total $ A ~ - - - - SPORTS SHIRT: Please send me _ __ Sport Shirt(s) <at> $A24.95 including postage. (Overseas orders please add $A3.00 for the additional postage). Size(s): S(Qty)_ M(Qty)_ L(Qty)_ XL(Qty)_ XXL(Qty)_ . Total $A_ __ BACK ISSUES: $A5.00 each (including postage). Overseas orders add $Al.00 per issue for postage. YEAR ISSUE YEAR ISSUE ISSUE YEAR ISSUE YEAR TOTAL$A SUBSC RIPTIONS: RATES □ NEW SUBSCRIPI'ION: Month Th Start □ RENE WAL:SubNo. (PLEASE TICK ONE) Start In Australia □ GIFT SUBSCRIPI'ION: Month Th Start Your Details Mr/Mrs/Ms: Address: Postcode 2 years (24 issues) 1 year (12 issu es) O$A84 O$A42 Australia with Binder(s) O$A105 O$A53 NZ & PNG (Airmail) O$A130 O$A65 Overseas Surface Mail O$A130 O$A62 Overseas Airmail O$A240 O$A120 Daytime telephone number. _ _ __ _ _ __ Enclosed is my cheque/money order for $_ _ _ or debit my III D '-="----"'='"-.J O "--"--'---'--' OI v1SA I l~ I l~I~ Card expiry date Signature _ _ _ __ _ _ __ _ _!_ _ Gift Subscription Details Message:._ _ _ _ _ _ _ _ _ _ _ _ _ __ Mr/Mrs/Ms: _ _ _ _ _ __ _ _ _ _ _ __ Address: _ _ _ __ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ __ _ Postcode_ _ __ ~ (02) 979 5644 Fax the coupon with your Credit Card details 24 Hours, 7 Days a Week 9am - 5pm Mon-Fri. Please have your Credit Card details ready. Mail coupon to: FREEPOST25 Silicon Chip Publications PO Box 139 Collaroy Beach NSW 2097 No stamp required in Australia Special project •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• This new colour TV pattern generator produces seven separate paUerns:checkerboard, crosshatch, dot, greyscale; white raster, red raster & colour bars. It will enable you to set your TV's convergence & purity for the best possible pictures. 16 SILICON CHIP colour pattern generator is an essential service tool for the TV serviceman since it provides known and standard patterns. On a well adjusted set, each pattern will be close to perfect, while on a poor set the patterns will be far from satisfactory. As a service aid, the pattern generator is invaluable for tracking down faulty circuit operation. The colour bar pattern is shown on virtually all television circuit diagrams as a standard staircase waveform. By comparing the expected waveforms with those found in the TV set when fed with the colour bar signal, it is often possible to determine the faulty section. Once the set is operating, the other patterns can be used to set and check the convergence and purity, and to make fine adjustments to optimise the overall performance. With the checkerboard pattern for A example, the frequency response of the video stages can be checked. When there is a poor high frequency response, the black and white edges of the pattern are smeared. The crosshatch pattern comprises 12 horizontal lines and 14 vertical lines. It is useful for adjusting picture geometry; ie, setting the correct height and width and minimising pin cushion distortion. Most important of all, the crosshatch pattern can be used for dynamic convergence adjustments. On a poorly converged set, the white lines will splay into red, blue and green lines at the edges of the screen. Similarly, the dot pattern, which is derived from the crosshatch pattern, is used for static convergence adjustments. On a poorly converged set, each dot will actually consist of blue, red and green dots which only roughly coincide instead of producing a perfect white dot. The white and red rasters are for ••••••••••••••••••••••••• purity adjustments. On sets with purity problems, the white raster (screen) may have blotches of red, blue or green. This may indicate the need to degauss (ie, de-magnetise) the metalwork around the picture tube. The generator produces the standard colour bar chart with colours from left to right: white, yellow, cyan, green, magenta, red, blue and black. The greyscale pattern is simply the colour bar chart with the chrominance signal switched off. This is not strictly a perfect grey scale since the luminance changes do not increment linearly from black to white. However, the resulting greyscale pattern can be used for setting up brightness and contrast. It can also be used to check for colour tinting which can occur with changes in brightness level. a •• e. Main features Despite the circuit complexity, the Colour TV Pattern Generator is very easy to build since virtually all the parts are mounted on a single PC board. An onboard RF modulator provides an output on channel 2 & there is also a direct video output available. The SILICON CHIP Colour TV Pattern Generator is housed in a plastic instrument case and is powered from a mains plugpack. The output is composite video or via an RF modulator set to channel 2. A rotary switch selects the patterns while a toggle switch selects either the greyscale or colour bars. All the pattern signals, sync and blanking are locked to a 4MHz crystal oscillator. This means that there is only one setting up adjustment and everything will remain in lock for the life of the instrument. Block diagram The circuit for the colour pattern generator is quite complicated with Build a colour TV pattern generator By JOHN CLARKE NOVEMBER 1991 17 I ◄ •• •• •• •• These four photographs show some of the patterns that are generated by the Colour TV Pattern Generator. They are, from top: checkerboard, greyscale bars, crosshatch & dot. In addition, the instrument can generate a colour bar pattern & white & red rasters for purity adjustments. its 16 ICs and all the interconnections. The block diagram of Fig.1 should be a help in understanding the circuit operation. We'll start at the top left-hand corner of the block diagram which shows the 4MHz crystal oscillator (ICla). This feeds a divide-by-16 circuit (IC2a, IC3, IC5a & IC6a) which produces the vertical crosshatch lines. These are a string of pulses 0.25µs long occurring every 4µs. A second divide-by-16 circuit (IC4, IC6b, IC5b & IC13a) provides the horizontal sync pulses which are 4µs long every 64µs . The frequency is therefore 1/64µs or 15.625kHz which is the standard line frequency. The same divide-by16 circuit also produces the horizontal blanking signal (lOµs pulses occurring every 64µs) and the vertical checkerboard signal (a square wave Bµs high and 8µs low). A divide-by-26 circuit (IC7a, IC5c, IC6c, etc) provides the horizontal crosshatch signal (64µs pulses occurring every 1.66ms). Note that strictly speaking, the division ratios quoted here are not precisely associated with the ICs mentioned but overall, the divisions are correct. The vertical and horizontal crosshatch signals are fed via NOR gate IClOa to produce the crosshatch pattern and through NAND gate IC9a to derive the dot pattern. A final divide-by-12 circuit (IC7b, ICld, IC8c, IC8d & ICZb) gives the vertical sync and vertical blanking signals. The repetition rate of these signals is very close to 20ms which is the standard field period. The blanking period is 1.66ms while the vertical sync period is 256µs. The horizontal checkerboard signal is also derived from this divideby-12 block. The horizontal sync and vertical sync waveforms are mixed together by OR gate IClDb to provide the composite sync signal. This is then applied to the colour encoder (IC16). Similarly, the horizontal and vertical blanking signals are mixed (by IC9b, IClOc & IClOd) to provide the composite blanking signal which is then fed to the colour encoder. The blanking signal is also mixed with the checkerboard, crosshatch or dot signals when required. The red and white raster, colour bars and grey scale are selected by the circuit blocks marked "bar select" and "preload red/white select". These two circuit blocks control the bar clock (IC14 & IC9d) and a down counter (IC15) which drives the red, blue and green inputs of the colour encoder (IC16). Note that the waveforms on the block diagram are all shown with the pulse going positive. This is done for clarity. The actual circuit waveforms, however, may be inverted to this. The colour bar video waveform produced by the pattern generator is shown in Fig.2. Circuit details Fig.3 shows the full circuit details. Most of the ICs used are high speed CMOS devices, necessary because of the 18 SILICON CHIP X1 4MHz _rC> """[_ ·4MHz CRYSTAL OSCILLATOR IC1a ~ +16 · Ic2a ,IC3 , IC5a ,IC6a --< ~ +16 IC4,IC6b, IC5b,IC13a - N ·I- - • 26 IC7a,IC5c,IC6c, IC8a,IC8b IC7b,IC1 +12d,IC8c, IC8d ,IC2b HOR IZONTAL ~ CROSSHATCH J__Jl_ -- 64~ 1.6ms 025y 4us VERTICAL CROSSHATCH HORIZONTAL CHECKER VERTICAL CHECKER I' JU1 8ltl XOR GATE IC11a 16us ~ 10~-64us - HORIZONTAL BLANKING '\ / -n1 Jl__J]_ POrrr64~ BAR SELECT S2a POSITION 6 IC9c,IC11 b, .IC13b RESET '-- BAR CLOCK IC14,IC9d I CLO;,K DOWN COUNTER IC15 -- RED GREEN --- '-- AND GATE IC9• ,,------ DOT CROSSHATCH j SWITCHING IC12a,b,c S2a POSITIONS 1,2,3,4,5 CHECKER , HATCH OR DOT BLANKING MIXER IC9b ,IC10c,IC10d HORIZONTAL SYNC PRELOAD RED/WHITE SELECT S2b NOR GATE IC10a VERTICAL SYNC ~ VERTICAL BLANKING ___L__J_ -ll:6us20ms • I SYNC MIXER IC10b INVERTED COMPOSITE SYNC CSYNC l CBLANK COLOUR ENCODER IC16 COMPOSITE BLANKING I COMPOSITE VIDEO OUTPUT TV MODULATOR ---Oou'VruT BLUE ~x~~ ~ VIDEO ~ OUTPUT 8.86MHz Fig.1: this block diagram shows the main circuit functions of the pattern generator. ICla & its associated 4MHz crystal form a crystal oscillator & this drives a number of divider stages & logic gates to derive the crosshatch, checkerboard & dot signals, & the horizontal & vertical sync signals. The red and white rasters, colour bars and grey scale are selected by the circuit blocks marked "bar select" and "preload red/white select". These two blocks control up/down counter IC15 which in turn drives the colour encoder (IC16). (IC6b) to produce the horizontal sync required high frequency waveforms. NAND gate ICla functions as the pulses. Note that the clock inputs of IC3 c:::ystal oscillator. One input is tied high so that the gate operates as an and IC4 are tied together so that all inverter. It is biased by a l0MQ resis- the Q outputs of these two dividers change state at the same time - giving tor and shunted by the 4MHz crystal. ideal synchronous operation. The 82pF capacitor at pin 4 and the The horizontal sync pulses are 4~ts 33pF capacitor at pin 6 provide corwide and occur every 64µs. The horirect loading for the crystal. The 4MHz square-wave signal from zontal blanking signal also occurs ICla is fed to IC2a which is a 74HC74 every 64µs but needs to be a 10µs D-type flipflop, connected to divide pulse rather than 4µs. To arrive at by 2. The resulting 2MHz signal is this, we can get an 8µs pulse at the then fed to the clock input of IC3 , a right repetition rate from the output 74HC161 4-bit synchronous binary ofNAND gate IC6b. IC13a, a 74HC74 D counter. flipflop, is used to extend the 8µs pulse to l0µs by taking .a further sigSignals from IC2a and IC3 are then fed to NAND gate IC6a and NOR gate nal from the Q3 output of IC3 . IC5a to provide the vertical crosshatch It works like this. Initially, when waveform. . the preset input at pin 4 ofIC13a goes low, the Q-bar output at pin 6 also The CARRY output of IC3 is fed to IC4, another 74HC161 4-bit synchro- goes low. This follows the output of nous counter. IC3's Q4 output and IC6b. Now when IC6b goes high again IC4's Ql , Q2 & Q3 outputs drive NOR after 8µs, the Q-bar output of IC13a gate IC5b and a 3-input NAND gate remains low until the clock input at pin 3 goes high 2µs later. Thus, we have the required l0µs horizontal blanking signal. The lkQ resistor and lO0pF capacitor at the preset input of IC13a provide a slight signal delay to prevent a "race" condition between the Q-bar output '.m d the clock input. Divide-by-13 The Q4 output of IC4 is used as the clock for the following divide-by-26 circuit consisting of IC7a, IC5c, IC6c, IC8a & IC8b. IC7a is one half of a 74HC393 dual 4-bit binary counter. Its Ql, Q3 & Q4 outputs are connected to IC6c, a 3-input NAND gate. When all three outputs go high after a count of 13, pin 8 ofIC6c goes low. This sets a flipflop consisting cross-coupled NAND gates IC8a & IC8b so that pin 8 of IC8 goes high and IC7a is reset. IC5 c, & 2-input OR gate is connected so that the clock input to IC7a is inverted. At the next high going clock pulse to IC7a, the output of IC8a (pin 11) goes high and pin 8 of IC8b goes low to release the reset on IC7a. IC7a is now ready to count on the next negative edge of the clock input. The reset signal for IC7a lasts for one half clock cycle or 64µs and this NOVEMBER 1991 19 1V PEAK -----,--W:.:.:H.::.:ll.:.E---l WHITE z ;:: c.., ~a: "' ffi a: w :l "' DV BLACK ....._____ 10-CYCLE COLOUR BURST LINE SYNC . PULSE Fig.2: this diagram shows the standard colour bar video waveform produced by the pattern generator. Note the leading line sync pulse & colour burst signals. becomes the horizontal crosshatch signal. Divide-by-12 The divide-by-12 circuit consists of IC7b, IC1d, ICBc, IC8d & ICZb. IC7b, the other half of the 74HC393 4-bit binary counter, derives its clock signal from the horizontal crosshatch; ie, the reset signal at pin 12 of IC7a. IC1d is a 2-input NANO gate which monitors the Q3 & Q4 outputs ofIC7b. On the count of 12, both inputs to IC1d are high and its pin 11 output goes low. This causes the pin 6 output of ICBd to go high and reset IC7b. When the clock input to IC7b subsequently goes high, pin 11 ofIC8a goes low and pin 3 of IC8c also goes low. The resulting output from IC8c is a 1.66ms pulse occurring every ZOms. This is the vertical blanking signal. IC2b is a 74HC74 D-flipflop which is used to delay the signal at pin 6 of IC8d by 256µs. This is necessary as will become clear in a moment. To get the 256µs vertical sync pulse, we need to cut short the length of the vertical blanking period. This is done using NOR gate IC5d which monitors the Q3 & Q4 outputs of IC7a. IC5d's output goes to NANO gate IC1b which also picks up the Q output of IC2b. The output of IC5d goes high at the beginning of the vertical blanking period and low 512µs later. Thus, the output of IC1b goes low 256µs after the start of the vertical blanking period (due to the IC2b delay period) and high 512µs after the start of the vertical blanking. This means that the vertical sync signal after inverter IC1c is high for 256µs every ZOms. This gives the desired timing of the vertical sync pulse with respect to the 20 SILICON CHIP vertical blanking pulse. The vertical sync at pin 3 of IC1c is combined with the horizontal sync at pin 4 of IC5b using 2-input NOR gate IC10b. This gives an inverted composite sync suitable for the TEA2000 colour encoder, IC16. Similarly, the vertical blanking at pin 3 of IC8c is combined with the horizontal blanking at pin 6 of IC13a by NAND gate IC9b to provide the composite blanking signal. The final composite blanking signal at the output of NOR gate IC10d (wired as an inverter) includes the checkerboard, crosshatch and dot patterns, if selected. The horizontal and vertical crosshatch signals are combined in NOR gate IC10a to obtain the crosshatch pattern and combined in NANO gate IC9a to obtain the dot pattern. The vertical checkerboard signal from Q2 ofIC7b is combined with the horizontal checkerboard signal at the Q1 output of IC4 using XOR gate IC11a. The outputs of IC9a, IC10a & IC11a connect to CMOS switches IC12a, IC12b & IC12c. The CMOS switch outputs are then commoned and connect to the pin 3 input of IC10c. The CMOS switches are controlled by rotary selector switch S2a. Normally, the control inputs of the CMOS switches are held at OV via 10kQ resistors. When a CMOS switch input is pulled high by rotary switch S2a, the corresponding pattern (checker, crosshatch or dot) is selected and fed through to IC10c. Colour patterns Positions 4 & 5 of rotary switch S2 are the white and red raster patterns respectively. These are produced by applying the white and red codes to IC16, the colour encoder. This is done by pulling two or more of the colour inputs (1, 2, 3, 4, 5 & 18) high (ie, to +5V). When all the colour inputs are high, the colour generated by IC16 is white. When only the red inputs (pins 1 & 18) are high, the colour generated is red. IC15 is used to generate the voltage levels for the blue, red and green inputs of IC16. It is a 74HC193 4-bit presettable, up/down counter which is wired to count down only. Only the three least significant outputs are used, Q1, Q2 & Q3. The A, B & C inputs are the preload inputs and control the Q1, Q2 & Q3 outputs respectively when the Preset Enable (PE) input at pin 11 is low. IC13b is a D flipflop which is clocked by the Q1 output ofIC4 while its CLR (clear) input, pin 13, is controlled by gates IC9c & IC11 b. IC9c receives the horizontal blanking signal at pin 4 and its pin 5 input is normally tied to OV with a 10kQ resistor. IC9c's output at pin 6 is thus normally high except when switch S2a is in position 6. Exclusive-OR gate IC11 b is connected as an inverter so that the CLR input of IC13b is normally low. When the clear input is low, the Q output ofIC13b is also low and so the IC15 down counter is preloaded with the voltage levels set at its A, B & C inputs. When the white pattern is selected (S2b at position 4), the A, B & C inputs of IC15 are all at +5V. This preloads the Q1, Q2 & Q3 outputs high and so IC16 is set to produce a white screen. When S2b is in position 5, the A and C preload inputs are pulled to OV and the B input remains high. This selects a low Q1 output for the blue inputs, a high Q2 output for the red inputs and a low Q3 output for the green inputs. Thus, IC16 produces a red screen. Colour bars When switch S2a is set to position Fig.3 (right): most of the ICs used in the circuit are high-speed CMOS devices to give the necessary frequency response. The device numbers can be directly related to the major circuit blocks shown in the block diagram (Fig.1). l VERTICAL CROSSHATCH +sv, ,41 74HC02 · • 11 • 31 ¥" 10 '::' . 10 10k 1_1)_ +sv · • HORIZONTAL ICROSSHATCH +5V ~ - - - - ~ - + 5 V- 33pFI 74HCOO +5V ◄ • , • +5V • .,. 1§. ' +5V +5V IC12c 1 PE· __ 1 2ICK ' S2a hH .~~k. IC15 74HC193 t ' 'I 021 2 ) ) ) ) ' I> S3 T l!! • ~ ·1 ~ 5.6pF.r 1 IRED qOLU 117 Ol 5.6pF! VC1 2·30pF IC16 TEA2000 t 12 ,04111 COMPOSITE BLANKING 330pF SYNC BLANK 16 COMPOSITEl10 SYNC HORIZONTAL SYNC VERTICAL SYNC HORIZONTAL BLANKING COLOUR 10k .,. IC11a 74HC86 IC4 74HC161 • • e e e • e • • 7 1CEP HORIZONTAL CHECKER 3x1N4148 > ,~ T 031 6 Ill l!.4 S2: PATTERN 1 : CHECKER 2 HATCH 3 DOT 4 WHITE 5 RED 6 BARS 121- 03 IC3 74HC161 • • e e e e e e e 1~ ·IC7a 74HC393 36k 11 12VAC PLUG-PACK 14 470 VIEWED FROM I +5V • • · 11 I 16VWT , 7'\ ~ _ .. Et:__:} C 01 BC337 +12V LED1 VERTICAL BLANKING ,i112 ~ • .. +0.6V IIN .,. o.1 I 680'1 1our, ~ GNO 02 -~- 13 JIJ RF OUTPUT _+5V .,. ~VIDEO OUTPUT mu _DUT _ 400mW -v~~!ff2E3 ·v+ 12 .,2v '~"' GND .,. 04 IC7b COLOUR TV PATTERN GENERATOR 01.:r POWER 8 19 04-113- UicK >--L---------------------------------------------------------------------------------J ~ co co ,_. ,_. :i:, tll t'l ~ ~ -r·· ~ 100 16VW 82pFI +5V. 10M; PARTS LIST 1 plastic instrument case, 205 x 158 x 62mm 1 PC board, code SC02210911, 175 x 142mm 1 Dynamark front panel label, 192 x 55mm 1 12VAC plugpack 1 4MHz parallel crystal (X1) 1 8.86MHz PAL TV crystal, 22pF series load (X2) 1 2-pole 6-position rotary switch (S2) 2 SPOT toggle switches (S1, S3) 1 5mm LED bezel 1 knob 1 RCA panel socket 1 cord grip grommet 1 VM416/A2E3 video modulator 1 3-metre length 0.8mm tinned copper wire 1 500mm-length 8-way ribbon cable 12 PC stakes Semiconductors 3 74HC00 quad 2-input NANO gates (IC1 ,IC8,IC9) 2 74HC02 quad 2-input NOR gates (IC5,IC10) 1 74HC10 triple 3-input NANO gate (IC6) 2 74HC7 4 dual D flipflops (IC2,IC13) 1 74HC86 quad XOR gate (IC11) 2 74HC161 4-bit synchronous counters_(IC3,IC4) 1 74HC 193 preloadable 4-bit up/down counter (IC15) 6, the blanking signal passes through IC11b to the CLR input ofIC13b. Thus, IC13b's Q output goes low during the blanking interval and high after the clock input goes high. The clock input to IC13b is from the Q1 output of IC4 and occurs 6µs after the horizontal blanking pulse from IC13a. Thus, the Q output goes high which releases the preset enable from IC15. The high Q output of IC13b also pulls up pin 4 of IC14, a CMOS 555 timer, which allows it to start oscillating. The 5.6kQ and lOkQ resistors at pin 7 and the associated 220pF capacitor set the frequency of the oscillator to about 255kHz. 22 SILICON CHIP 1 74HC393 dual 4-bit counter (IC?) 1 74HC4066 quad analog switch (IC12) 1 7555 CMOS timer (IC14) 1 TEA2000 colour encoder (IC16) 178123-terminal 12V regulator (REG1) 1 7805 3-terminal 5V regulator (REG2) .1 BC337 NPN transistor (01) 1 5mm red LED (LED1) 4 1N4002 1A diodes (D1-D4) 5 1N914, 1N4148 switching diodes (D5-O9) 1 6.8V, 400mW zener diode (ZD1) Capacitors 1 470µF 25VW PC electrolytic 2 470µF 16VW PC electrolytic 1 100µF 16VW PC electrolytic 2 1µF 16VW PC electrolytic 10 0.1 µF monolithic 2 .01 µF ceramic 1 330pF ceramic 5% tolerance 1 220pF polystyrene 2 100pF ceramic 1 82pF ceramic 1 33pF ceramic 2 5.6pF ceramic 1 2-30pF trimmer Resistors (0.25W, 5%) 1 10MQ 1 36kQ 1% 9 10kQ 1 5.6kQ 1 2.2kQ 31kQ 1 910Q 1% 1 680Q 1 470Q 1 390Q 1 330Q 0.5W 1 100Q The oscillator output at pin 3 is gated via IC9d which allows the signal to pass through to the clock input of IC15 when its pin 10 input is high. Normally, this input is held high via diodes D5, D6 & D7 which connect to the Q1, QZ & Q3 outputs of IC15. IC15 thus begins counting down, starting with Q1, QZ & Q3 high (ie, at +5V) and ending with all the Q outputs at ground. The intermediate counts, where there is a mix of high and low values at the Q outputs, provide the different colours in the colour bar pattern. When all the Q outputs are at ground, the colour is black and the cathodes of D5, D6 & D7 go low. The clock signal to IC15 is thus disabled and so the black signal from IC16 continues until the next blanking period. Note that the design provides extended white and black colour codes to IC16 to allow for the overscanning of the picture tube. Colour encoding We have already mentioned IC16, a Philips TEAZ0O0 colour encoder. It only requires the sync and blanking signals to be applied to its pin 16 & 17 inputs to produce the requisite PAL colour signal. To achieve this, the colour IC uses an 8.86MHz crystal to generate the 4.43MHz colour burst and chrominance information. A ramp generator, which operates in synchronisation with the composite sync, is controlled by the RC time constant of the 36kQ resistor and 330pF capacitor at pin 15. This time constant controls the position of the colour burst signal after the composite sync signal. The 1kQ and 910Q resistors at pins 7 & 8 set the luminance level for the composite video output at pin 6. Pin 10 contains the chrominance signal which is switched via a .01µF capacitor to ground to disable colour in the 1, 2 & 3 positions of switch SZb and in position 6 when S3 is closed to provide the grey scale. The composite video output at pin 6 is attenuated using a 390Q and 470Q resistive divider. The attenuated signal is buffered with transistor Q1, which is connected as an emitter follower. Its output provides a video signal to the RF modulator and to the video output socket. Both output signal paths are via 470µF electrolytic capacitors. Diodes D8 & D9 clamp the video signal to the RF modulator at ground level (necessary for correct modulation levels). The 6.8V zener diode provides the necessary supply rail for the modulator. The output of the RF modulator is at channel 2. Power for the circuit is derived from a 12VAC plugpack which drives bridge rectifier D1-D4 and a 470µF capacitor. The resulting DC rail is then fed to 3-terminal regulators REG1 & REGZ to derive the necessary +12V and +5V supply rails. Next month, we will describe the construction and testing of the pattern generator. SC WCOD FOR CHIPS... WCOD FOR CHIPS...WCXJD FOR CHIPS... WCXJD FOR CHIPS... wa>D FOR CHIPS... wa>O FOR CHIPS...WOOD FOR CHIPS... WOOD ~ Here's a few hot tips ... "<~ "'~__)~ ~ ~ ". 1 1 Welle~ Sold!Jring Staltons WTCPS "'eller EC1001O 1111 1 \ ::,.._ ~\ ' · Transformer powered low voltage soldering station. Features Welrer One of the Favourites! • • • • e • • • The ultimate cordless .soldering iron • No electricity • • • • • No batteries Gas operated Ready to use in 30 seconds Refilrln moments Hot air blower and mini-torch burner • Up to 3 hours use from one filling Weller Pyropen weighs only 90am and offers temperature control from 200 to 500°C . II has a built-in lgnitor and gas level indication. Flame and temperature are easily controlled by sliding lever. Choice of 14 tip shapes plus 4 gas/hot air blowers. Can be useafor brazing up to 1300°C with special tip. Supplied in metal storage box containing tip wipper. ~~r~-~~~i\"t~~~r~~~nl~olling Electronic Temperature control to protect temperature sensltlve within ±6°C over the range 177°C components. to 454°C • Grounded tip protects voltage Dial readout in calibrated and current sensitive steps components. Temperature control maintained • 48W stain.less steel heater for ±10% supply variation construction . Rapid response platinum • Non_-burning silicon rubber cord temperature sensor with full • 15 tip sizes - 0.8mm to 6.00mm J)roportional control • 11Secs to recover for 37°C drop Thyristor power control with zero• • Choice of tip temperatures voltage switching 315°C/60'.l°F, 370"C/70"F, Grounded tip 430°C/800°F $137.00 $165.90 42W/24Vac transformer operation ax tax $116.25 · All Irons P&P $10 10 second recove,y 14 tip styles • 0.8 to 5.0mm We stock a wide range of Weller Tips. diameter s•c • Now Stocking Weller WPA2 Pyropen $195.00 ~-,4 ex tax $175.50 y\ Talk to us about all your tool requirements - we have a wide range and everything for the professional or hobbyist MAGGYLAMP Now fitted with SOW heater, NEW Hot air nozzle makes it easier to remove surface mount devices. Price is unchanged at $399 ex tax ($478 inc taxl Stand $42.50 pens· even your dentures! Let the millions of tiny 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 a lot more. Our's are only $150 SMD Removal Kit. NEW MINI-VAC Just what the Serviceman needs! Special Purchase ROLACASE 1OO's of uses for this handy batte,y powered mlni•vacuum cleaner. Portable Storage Clean your computer keyboard, slides and projectors, viaeo Systems equipment, stereo's. Supplied with Comes with filter pipe, stainless ~~~'ef ~a~dh~~~~ ~~~h~~r nozzle. $32.80 Why Pay Up to $80 for a Mouse? Genuine 3 button mouse offering 260·2600dpl resolution. Microsotv Mouse Systems compatible (proper slide switch). Includes mouse driver, test program, read•me files etc on 51 /4 disl<. Full instructions. Excellent value at only $34.95 Power Supplies two brushes, straight and angled connecting pieces. Runs off 9V alkaline batte,y plus socket for 9V ac plug pack connection. · Normally sells for around $16.00 We have them for only $11.95 GP03020 DC Power Suppiy • 2 by 30V/2A variable outputs • 4 analog meters e Fixed 5V/3A and 5V/1A OUIJ)Uts $725.00 GPC3030 DC Power Supply • 2 by 30V/3A variable OU[pJts • Fixed 5V/3A output • Two 3 1/2 digit LED Panel Meters . $743.00 GPR3030 DC Power Supply • Single 30V/3A output • Flne~oarse control $380.00 Professional !~E IP.~~,i~_,o~~~s~r batteries yet it gives the equivalent of a 10 to 60W iron. Up to 90 minutes continuous use from a tnil;,~g-~ ~tfet~:e:itas high Includes one soldering lip, a hot knife, blow ton:h and hot blow. Cap contains a flint lighter. Comes in a handy case (with stand for the iron) almost fits in vour pocket. $69.95 PORTASOL "STANDARD SOLDERING IRON We've sold hundreds of 'em to servicemen and technicians. Complete and ready to use with just the iron and bit $39.95 Spare lips are each $12.95 Portasol gas speclfically designed for PORTASOL 150g $ 6.95 • • • • ideal for vehicle storage Easily indexed Take with you to the job Static conauctive to prevent damage to delicate components • Ideal for mining, gas etc indust,y where extra saiety is required e High impact ABS • Infernal Dimensions 360x360x75mm • Choice of two types Blue, single compartment $57.20 Orange, diYided into 20 compartments $64.95 • Storage rack holds 3 cases, for vehicle or bench $155.00 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 facIllties 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 ~~~?~rn~~o~rs&t{IJe~l~mulate Triggers can be defined based on error conditions or data to Initiate or terminate monitoring sequences. • Handles baud rates up to 115.2kbaud. • View each byte in ASCII or EBCDIC, decoded to hex, decimal, bina,y or octal 250gm 500gm ~ ~ C) ~ ~ ~ ~ ~ '6 ~ ~ C) ,;J;; ~ ~ Solder Wick $2. 95 Solder 1.25, 0.9 and 0.71mm $3.00 $15 .OD ~ Fluke Multimeters • Magnifies any object under a clear cool light leaving both hands free. • 127mm bi-convex lens, 4.00 dioptres, 254mm focal length • Flexible arms for easy positioning Value at $250.0tr The NEW \ \ SCSOOOA DIC . Ultrasonic Desoldering Cleaner The latest high•tech w~ to clean Tool. PCB's, switches, watches, drafting II you 're working on surface mount devices you 'II need the ~ SerialTest serial data analysis on your PC 18821 w;,~1;,~1 - · clio ict ~ii~ tie .,..,.. bop: ... t,:eH IDIH " ' f ir11 l~ll~• ol ,p,., clio i~ . It,,, u :scr ""' --~ le nff to o i l ;J:: • Writes captured data directt to ~~~et~ allow maximum cap ure • CRC checksum calculations If you want the best, • Auto-configuration to any of the comms ports 1 to 4 then Woody has 'emf • Time-stamping (absolute and Fluke 45 ....... $1450.00 relative) including delta lime New 73-11 ....... $210.00 e calculations Split line DTE over DCE display $395 plus sales tax New 75-11 ....... $312.00 $1 Ofor a demo disk, New 77-11 ....... $354.00 Send refundable on purchase. 83 ................ $478.00 · 85 .............. .. $576.00 Test Leads 87 ................ $690.00 ETS1111 Oscilloscope Probe All these prices Kit Switchable x1/X10 $51.95 include tax - call for TLK01 Silicone universal tax free pricing multimeter test lead kit Handy Probe / Multimeter., Ideal for tight spots No need to tum '.l'_our head to read tllis multimeter. The readout is right there in the probe! Auto and manual ranging, 3.5 digitlarge 14mm LCD display· all in a handy probe. Lojjic testing function for CMOS/TTL. Data Hold 6utton, Diode test, Continuity buzzer. Dlspl~ shows all functions. Protected to 21iOV • DC Voltage from 200mV to 500V • AC Voltage from 2V to 500V • Resistance from 2000 to 20MO • AC/DC Current to 200mA• Continuity check to 2k0 • Logic Testing to 1MHz and ]I'S • Diode Test 2V $55.00 Geoff Wood Electronics Pty Ltd (inc 1n N s W) $54.95 QUV-TB/N Industrial EPROM Eraser • 125x200mm slid•out tray with anti•static pad • UV indicator • 7700 hour lamp life • 15,000microwatt/sq cm intensity • Safety interlock switch $133.80 ex tax $155 .20 inc tax Don't forget we slack a lull range al EPROMs and other microprocessor chips. 229 Burns Bay Road, (Corner Beatrice Street), Lane Cove West N S W Mail Orders to - P O Box 671, Lane Cove N SW 2066 Telephone: (02) 428 4111 Fax: (02) 428 5198 8.30am to 5.00pm Monday to Friday. 8.00am to 12 noon Saturday Mail Orders add $5.00 min to cover postal charges Next day delivery in Sydney add $5.00 All prices INCLUDE sales tax unless stated otherwise Tax Exemption Certificates accepted if the line value exceeds $10.00 BANKCARD, MASTERCARD, VISA, CHEQUES or CASH cheerfully accepted. '6 f'> ~ c:, O 11 lJ C) ::t: ~ ~ 0 ~ C) ;i;; ~ ~ c:, ~ C) ;i;; ~ ~ ~ 2 ~ ~ ~ 2'6 f'> ~ ~ 2 "5 f'> ~ Deter car thieves with this simple FLASHING ALARM LIGHT A simple flashing light may be all that is needed to deter a would-be thief and protect your car from theft or damage. It's easy to build and switches on automatically as soon as you turn off the ignition. By SYD McKITRICK* To be effective, an alarm deterrent light must meet three basic criteria. First, it must be bright so that it can be easily seen during the daytime. Second, it should have a professional appearance, to give the impression that it is part of a working alarm sys- tern. And third, it should come on automatically whenever the ignition is switched off - after all, what good is an alarm flasher that you've forgotten to turn on? This simple alarm flasher meets those three basic design aims. It can This larger-than-life view shows the completed PC board, ready for installation in the plastic bezel. A small doh of silicone sealing compound cushions the lamp from the PC board to reduce stress on the lamp leads due to vibration. 24 SILICON CHIP be easily fitted to any car and flashes a small light globe inside a large red bezel to provide a really effective warning - just like a real car burglar alarm. Although several commercial flasher units are already available, this kit will cost considerably less to build, will look just as good, and will survive almost anything the 12V automotive electrical system can dish up. In other words, you get a product that's just as good for less money. Isn't that what building kits is all about! Description The deterrent light is built on a small PC board which is designed to fit inside a ready-made mounting bezel. There are just three wires to connect and these go to ground, a permanent +12V supply rail (via the fusebox) and a switched +12V supply rail (from the "accessories" output of the ignition switch) . When the ignition switch is "on" the deterrent light will be disabled but as soon as the ignition switch is turned to the "off" position the light will begin flashing automatically. Since no extra switch is required to control the flashing light, you don't need to remember to turn it on or off. Before deciding on the final design, we looked at several different ways to attack this project. In the end, the humble 555 timer IC appealed because of its low cost, simplicity and ability to directly drive a light globe. The rest of the components are there mainly to protect the 555, while a 01 1N4004 You can now afford a sate II ite TV system 1sn r------------.---4rl'-H+-Wf...-0+12V IC1 For many years you have probably looked at satellite TV systems and thought "one day". 555 You can now purchase the following K band system for only 1k ' - - - - - - - -- -------------------QCHASSIS $995. 00 B EOC VIEWED FROM BELOW This is about 1/3 the price of corn parable systems FLASHING ALARM LIGHT Here's what you get: Fig.I: the circuit uses 555 timer ICI to flash the lamp at a I-second rate. QI turns the 555 on or off automatically in response to the ignition switch input, .. A 1.8 metre pressed steel prime focus dish antenna, complete with all the mounting hardware - as well as a self supporting ground stand . while ZDI protects the circuit from high-voltage transients. single transistor provides the automatic on/off function. How it works Fig.1 shows the circuit details. ICl is the 555 timer and is wired as an astable oscillator. However, the circuit configuration is somewhat unconventional in that the lamp is not driven by ICl 's pin 3 output. Instead, it is connected between the positive supply rail (+Vee) and pin 7, which is the open collector output of the internal discharge transistor. The maximum allowable supply voltage for a 555 is 16V and so protection against high voltage transients is provided by a 15Q resistor and zener diode ZDl. The associated lµF capacitor provides a low impedance supply for the 555, thus preventing problems that can otherwise occur each time the 555 switches from one state to another. Diode D1 protectsthe circuit against reverse polarity which could occur accidentally during initial installation, or if the 12V battery is removed and then later reconnected the wrong way around. Without D1, the 555 timer .. One super low noise LNB (low noise block converter) l.4dB or better. PARTS LIST 1 12V 55mA lamp (LP1) 1 red bezel, DSE Cat. ZA-5730 1 PC board, code ZA-1394 1 35mm length of 15mm-dia. heatshrink tubing 3 1-metre lengths of hookup wire (red, white & black) 1 cable tie .. One KU band feedhorn and all the mounting hardware as well as a magnetic signal polariser. .. 30 metres oflow loss coaxial cable with a single pair control line. .. A 99 channel infrared control satellite receiver with adjustable IF and audio bandwidth, polarity, and dual digital readout. The IR control unit has a range of approx. 10 metres. Semiconductors 1 555 timer (IC1) 1 BC548 transistor (01) 1 1N4004 diode (01) 1 15V 1W zener diode (ZD1) Before you receive your system the unit is pre-programmed to the popular AUSSAT transponders via the internal EEPROM memory. This unit is also suitable for C band applications. Capacitors 2 1µF 25V monolithic Resistors (0.25W, 5%) 1 820kQ 1 10kQ 1 1kQ 1 15Q CALL, FAX or WRITE to AV-COMM PTY LTD. PO BOX 386, NORTHBRIDGE NSW 2063 PHONE (02) 949 7417 would still be protected by ZDl which would become forward biased. However, the 15Q resistor would protest strongly by producing a stream of black smoke! 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. The kit comes complete (Cat K-4200} and sells for $A9.95 plus $A3.00 p&p or $A6.00 p&p for airmail. Note: copyright of the PC board associated with this project is retained by Dick Smith Electronics. * R & D Department, Dick Smith Electronics. FAX (02) 949 7095 All items are available seperately. Ask about our low noise 'C' band LNB, and other inter esting products. All systems are provided with dish pointing details. ----------- 1 Yes Garry, I Please send me more information I on your K band satellite systems. I I Name ............................... ........ I I I I Address ........................ ........... I I ................................................... I I ........................... P/Code ........ .. I I I •. ~~~~~~~~8 .......................... ~;;;~ ..• ------------NOVEMBER 1991 25 ~i1 r,:,, I LAMPG,,... - -~ 01 15\l r-----• 12V FROM BATTERY ·.zo1 ·=>-=•,.__. -~ - C H A S S I S lOk'------.-jmrrrit SWITCH Fig.2: install the link under ICl first, then carefully install the remaining parts on the PC board as described in the text. The three external leads & the lamp leads are installed on the copper side of the board, as is the lµF capacitor beneath IC1. Ql is mounted face-down on the board, with its top butted against the IC pins. Now let's assume that power has been applied to the circuit and that the ignition switch is turned on. In this situation, Ql is biased on and so the lµF timing capacitor on pins 2 & 6 ofICl is kept discharged. Because pin 2 is below the trigger voltage (1/3Vcc), the 555 timer will be held in the triggered state and the open collector output at pin 7 will be non-conducting. This means that the lamp will be off, since only a few microamps of current can flow through it via the 820kQ resistor and Ql. When the ignition switch is turned off, Ql also turns off since it no longer receives base bias current via the l0kQ resistor. The lµF timing capacitor now charges towards the positive supply rail due to the current passing through the light globe and the series 820kQ timing resistor. When the voltage across the capacitor reaches 2/3Vcc, ICl resets and pin 7 switches low and lights the lamp. The lµF timing capacitor now discharges into pin 7 via the 820kQ resistor until, after about 0.5s, it reaches 1/3Vcc. At this point, ICl triggers again, the discharge transistor on pin 7 turns off, and the lamp goes out. The lµF timing capacitor now charges towards 2/3Vcc again and thus the cycle is repeated indefinitely until the ignition switch is turned on again. Provided the recommended bulb is used, the package dissipation is quite low and the circuit operates reliably in very high ambient temperatures. In fact, one of the prototypes was tested at an ambient temperature of 120°C and, apart from the flash rate ·increasing due to the temperature characteristic of the timing capacitor, the circuit continued to work. Construction Begin construction by taking a close look at the PC board. Some of the copper tracks run quite close together and it is worthwhile checking that none of these are bridged due to incorrect board etching. If in doubt, use your multimeter to ensure that there are no shorts between adjacent tracks on the board. At this stage, you should also check that the board fits inside the bezel. If it doesn't fit, carefully file the edges of the board until it does. A soldering iron with a fine tip is required for tp.e assembly work and it must be clean and freshly tinned. Fig.2 shows the parts layout on the PC board. First, install the wire link, using a short length of pigtail cut from one of the resistors. This link fits under ICl, so it needs to go in first. Next, install the three 1-metre long connecting leads. To do this, remove approximately 5mm of insulation from the ends and insert the wires into their pads from the copper side of the board. Bend them over so that they run parallel to the PC board towards the light globe end, then solder the wires and cut off any excess wire that protrudes through to the component side. The four resistors can now be installed. In each case, you will have to bend the pigtails close to the resistor body so that it fits on the board. The same goes for diode Dl which can now be installed, along with zener diode ZDl. Check that these two components are mounted in the correct locations and that they are correctly oriented. Before soldering in ICl, position the lµF timing capacitor on the underside of the PC board so that its The completed PC board is slid inside the plastic lamp bezel until the cable tie touches the end of the collar. It is then secured to the bezel using heatshrink tubing which also serves to anchor the external leads. RESISTOR COLOUR CODES 0 0 0 0 0 26 No Value 4-Band Code 5-Band Code 1 1 1 1 820kQ 10kQ 1kQ 15Q grey red yellow gold brown black orange gold brown black red gold brown green black gold grey red black orange brown brown black black red brown brown black black brown brown brown green black gold brown SILICON CHIP CV:;L=AM=P==~/::::===:::;PtJC;;;B/;::=:::iCABLE TIE ~ I\ COPPER SIDE CONNECTING WIRES Fig.3: this diagram shows how the lamp, cable tie & external leads are arranged. LAMP I -j -, l-i=..=-:_:-:_::-::_:-r=-=.:-=-=-J=-,:-- \ BEZEL Fig.4: the cable tie acts as a stop when the board is slid into the bezel & ensures' that the lamp is correctly positioned. leads pass through the holes provided for it (between pins 1 & 8 of ICl). Bend it over so that it lies flat against the board (see photo) and cut off any excess pigtails that protrude through to the component side. This done, remove the capacitor, install ICl on the component side of the board and solder pins 2-7. Now re-install the capacitor and solder the two remaining IC pins and the capacitor leads. ".:he transistor is mounted with the flat face of its body against the board and its top butted against pins 1 & 2 of the IC. Its collector and emitter leads are bent close to the body so they fit into their respective holes, while the base lead is bent so that it fits into its hole (beneath the lµF decoupling capacitor). Solder the transistor leads, then install the capacitor and the light globe (see Fig.2). To reduce stress on the light globe leads, place a small dab of silicone sealing compound between the globe and the edge of the PC board. The unit is now ready for testing. Testing To test the unit, just connect a 12V DC supply between to the OV and +12V leads and leave the +12V ignition lead disconnected. The globe should immediately begin flashing at a rate of approximately once per second. If this checks out, connect the +12Vignition switch lead to the +12V supply as well and check that the globe stops flashing. It should immediately start again when the ignition switch lead is disconnected. If the unit doesn't stop flashing when you connect the ignition lead to +12V, check transistor Ql. If you can't get the unit to flash at all, check that ICl, Dl and ZDl are all correctly oriented, and that Ql is not shorted between collector and emitter (try removing it from the board). Also, check that pins 4 & 8 ofICl are at +12V and that there are no shorts on the copper side of the board. Assuming everything checks out, run the three external leads towards the light globe end of the board and install a plastic cable tie as shown in Fig.3. This cable tie should sit in the small gap between the four components at the edge of the board and the body of the lµF decoupling capacitor. The locking end of the cable tie should be positioned on the component side of the board, directly above ZDl's cathode lead. Pull the cable tie tight, then bend the connecting leads back over the cable tie so that they now run away from the light globe (see Fig.3). This done, push the completed board up inside the bezel until the cable tie touches the end of the plastic collar (see Fig.4). Finally, install heatshrink tubing over the exposed PC board and the non-threaded part of the collar. This will hold the PC board in place and, together with the cable tie, serve to anchor the connecting leads. Installation To install the unit, first find a suitable location where the flasher will be visible and where there is adequate space behind the panel to accommodate the length of the bezel (approximately 40mm). After that, it's simply a matter of drilling a 15mm diameter hole to mount the bezel and connecting up the three supply leads. Make sure that the permanent +12V supply comes via the fused side of the fusebox and that all connectrons are secure and covered in insulation. If you don't wish to drill a hole in the dashboard, try mounting the bezel in the cigarette lighter holder. All you have to do is wrap some plastic insulation tape around the collar of the bezel until it is a snug fit and then carefully push it home. In most cars, you should have little difficulty in routing the connecting leads through a gap in the back of the holder. SC A small 3mW 670nM visible laser diode head . Just connect it to a battery via a switch. Produces a well collimated beam. You could pay three times our price for a laser pointer or gun sight that uses a similar head . $199 A complete mains filter employing two inductors and three capacitors fitted in a metal shielded IEC socket. We include a 40 joule varistor with each filter! $8.90 ea. or 10 for $65 INFRA RED NIGHT VIEWER MAINS SWITCHES Stock up on these modern, high quality, plastic panel mounting mains rated switches, at a fraction of their real prices: Large 3A, with green rocker and black bcdy $1.20 ea . or 10 for $7 Large 15A , with black rocker and a black body $1.50 ea . or 10 for $10 Small 4A illuminated type, with a red rocker and black body $1.50 ea. or 10 for $10 Not a complete kit, but just the absolute essentials: A new 6032 IR tube and a ready made power supply. You get the tube, the supply, a circuit and basic instructions. $150 ARGON LASER TUBE A used, but guaranteed Argon laser tube with . It needs forced air cooling , 3V at 25A for the filament, 400V trigger voltage, and 90 to 100V across it, at about BA to run. All this to produce minimum output of 30mW, of BLUE BEAM! For INFRA RED LASER DIODES Brand new 5mW 780nM 820nM IR Laser diodes. Visible in low light. Some data/application circuits provided . A suitable driver circuit and the components for this circuit are included. Excellent for IA sights, data links, high quality audio links, security perimeter protection , laser "bugs", etc. $30 Need a collimating lens and a heatsink to suit? $20 the more serious laser enthusiasts! We should have suggested power supply circuits . $800 VISIBLE LASER DIODE BARGAIN We supply a used and guaranteed 3mW, 670nM visible laser d iode, a heatsink, a coll imator, a simple constant current driver circuit and components to suit. A little effort is required to mount and adjust the co llimator, but look at the price $94 12V OPERATED GAS LASER BARGAIN SOME UNUSUAL COMPONENTS A used but guaranteed Hall Effect !Cs $2 ea or 1mW He-Ne tube, and our reliable 12V UNIVERSAL LASER POWER SUPPLY KIT. The supply and the tube fit into inexpensive 50mm SWV plast ic tubing . One tube and one supply for $99. And if you want to add an extra tube to the bargain, just add an extra $25. Yes, two tubes and one supply for a total of $124! Need mains operation? We 10 for $15 1000 pF 15KV Capac itors S12 ea or 5 for $45 11KV Diodes $1.50 ea or 10 for $10 TV Triplers $12 ea or 5 for $50 15KV EHT Power Supply (used) $45 or 3 for $100 Photo Multiplier Tubes can provide a similar package with the same tubes , and a small professional, fully potted, Broken Silicon Solar Cells. Enough for 6V <at> 1.5W 240V laser power supply. RING . $9 $90 Some of the above items are in LIMITED SUPPLY ANY OR AS MANY ITEMS FROM THIS LIST DELIVERED BY SKYROAD EXPRESS TO YOUR DOOR : $10 OATLEY ELECTRONICS PO BOX 89, OATLEY, NSW 2223 Telephone: (02) 579 4985 Fax: (02) 570 7910 Certified p&p: $6 in Aust. NZ (Airmail) : $10 Melbourne Distributor: Electronics World (03) 723 3860 or (03) 723 3094 NOVEMBER 1991 27 FREE CALCULATORS - AMAZING OPPORTUNITY An American lndu1trlall1t once remarked "I believe that half of our advertising 11 Ineffective - the trouble Is, we don't know which half!" Well - as the year draws to a close we've decided to conduct a survey on our advertising I.e. to see where our advta are noticed moat. So when you see this notice slmply ring us Toll Free on 008 999 007, advising us which magazine you saw the advt and we'll be dellghted to send you absolutely without charge one of our fantastic X 2110 Deak Calculators - there la no obllgatlon - you do not need to make any purchase. (Limit one per customer). Sensational Value On UHF Alarm Systems Main Control Receiver The main control receiver runs on 240V AC with a 12V 1.2Ah battery for emergency backup. The range between the transmitters and the receiver is normally 80 metres in open space. Feature■: • Wireless reception of external and internal sensors & detectors• Selectable home or away modes for selecting internal or external arming or just external to allow movement inside the buildin'g • Built in piezoelectric siren gives different signals to indicate different functions • Sends signal down power line to activate remote siren • Programmable arm/disarm switch buttons PaHlve Infra Red Movement Detector Ideal for the loungeroom, family room or hallways. Mounts up on the wall or bookshelf. Detects movement within an area of 9 x 9m. Go anywhere 240V malna power from your car battery with thla lant■ attc 12V DC to AC Inverter. This compact inverter will power lights, power tools, electric shavers, radios etc. A must for farming, camping, mining, boating and wherever 240V power isn't available. Feature■ : • Complete with over current circuit breaker • Fused 240V output • Built in panel meter to monitor output voltage • Strong steel _chassis. This unit is a line carrier receiver, ie. plugs into 240V AC and receives signal through AC line. Front Door Remote Keypad This handy unit virtually duplicates the function of the main control unit but at a more convenient location, ie. just inside the front or rear door etc. System can be armed or disarmed without the need to go to •• , main control unit. SYSTEM 3 Includes: 1 x Main Controller 3 x Remote Reed Switches l x Remote PIA Movemen! Detector 1 x Remote Keypad 1 x Remote Siren Plus 4 Bonus Large Alarm Warning Stickers Thll Month Only $ 399 lncludea: 1 x Mair. Controller 3 x Remote Reed Switches Plus 4 Bonus Large Alarm Warning Stickers Thl1 Month Only NORMALLY NORMALLY~ lncludea: 1 x Main L:ontroller 1 x Remote Reed Switch 1 x Remote PIA Movement Detec tor 1 x Aeniote Keypad Plus 4 Bonus Large Alarm Warning Stickers $249 Thi• Month Only $S,:M; $299 NORMALLYSS,36'" Quality Speaker Bargains Polypropylene Poly Emulsion Coated Cone 10" Woofer 80 Watts RMS C 3065 U9:t,o $60 Excellent bau reglat1tr performance Rated Power Input. ... BOW Max. Power Input . . . .. 130W Impedance (400Hz) ... 8 Ohm Frequency Response . lo - 4kHz Resonant Frequency . . 28Hz(+/-5Hz) Sensitivity ............ 97dB/W(0.5m) C 3026 $.9.Sh5 $85 12" Woofer 100 Watts RMS 12" Woofer 80 Watts RMS Rated Power Input .... 100W Max. Power Input , .... 1SOW Impedance (200Hz) ... 8 Ohm Frequency Response . lo - 3kHz Resonant Frequency .. 30Hz(+/-6Hz) Sensitivity ............ 98dB/W(0.5m) Rated Power Input. ... BOW Max. Power Input ..... 160W Impedance (300Hz) ... 8 Ohm Frequency Response . lo - 3kHz Resonant Frequency .. 25Hz( +/-SHz) , Sens1t1v1ty . . . , , ....... 98dB/W(0.5m). C3070~ $85 C 3030 $.l,2&:oo $105 . Dome Tweeter With Ferro Fluid 60 Watt Max. Power. Silky smooth frequency response 1.SHz to 20kHz. Wide angle dispersion. Massive power handling capacity. Diam 94mm. High spectrum. Purity. Incredible low price! C 3012 S2&:so $12 .00 10up$10.oo Thla Month Up to 30% Off 10" Woofer 60 Watts RMS Rated Power Input . . .. 60W Max. Power Input ..... 100W Impedance (300Hz) ... 8 Ohm Frequency Response . lo - 4kHz Resonant Frequency .. 45Hz(+/-9Hz) Sensitivity .. . ..... , ... 98dB/W(0.5m) Superb Dome Tweeter Bargain of 1991 Less Than ½ Price! With B■rlum Ferrlte magnet ■. Very efficient • extremely low dlatortlon (we aupply theae ,., ,vera to aome highly reapected speaker ayatem maker•) Carbon Fibre 6½" WQofer 30 Watts RMS Rated Power Input .... 30W Max. Power Input ..... 70W Impedance (300Hz) ... 8 Ohm Frequency Response . lo - 6kHz Resonant Frequency .. 65Hz(+/-13Hz) Sensitivity. . ..... 97dB/W(0.5m) C3034~s$69 8" Woofer 60 Watts RM Rated Power Input .. . . 60W Max. Power Input ..... 100W lmpeaance (400Hz) . .. 8 Ohm Frequency Response . lo - SkHz Resonant Frequency .. 50Hz(+/ -10Hz) Sensitivity .. , ......... 98dB/W(0.5m) C 3036 $J...1,5".'s5 $89 15" Woofer 100 Watts RMS Rated Power Input .... 120W Max. Power Input .. , . . 200W Impedance (200Hz) ... 8 Ohm Frequency Response . lo - 1SkHz Resonant Frequency .. 25Hz(+/-5Hz) Sensitivity ......... , , , 98dB/W(0.5m) C 3075 $ ~ 0 0 $95 Rated Power Input. ... 100W Max. Power Input . .. .. 200W Impedance (400Hz) ... 8 Ohm Frequency Response . lo - 3kHz Resona~! Frequency , , 25Hz( +/-SHz: Sens1t1v1ty ......... , , . 98dB/W(0.5m) C 3032 $ ~ 0 0 $169 With Bartum Ferrite magneta. Similar In performance to our emulsion cone range but with quite aatonlahlng power handling capacity 4-Channel Lightin Desk S/C JUNE/JULY '91 This 4-channel lighting desk is intended for theatre, disco and music group applications. It has heavy duty circuitry and is able to cope with spotlights rated up to 1000 watts or more. $329 .00 Digital Altimeter 120 Watt Public Add This professional quali)y Public Address Amplifier offers performance equal to or better than commercial units at about half the price. Ideally suited for Halls, Churches, Clubs and even temporary setups. lnputa 2 balanced microphones with 3 Pin XLR connector's. 2 Auxiliaries suitable for direct connection to CD player, tuner etc. Output& 4 Ohm , 8 Ohm or 100V line output configuration Power Output (RMS) 125 Walls into 4 Ohms; 90 watts into 8 Ohms; 120 watts into 100V AC line. Get 240V AC Malna Power From Your 12V Battery With Thla Hendy Inverter This inverter has the capability to produce 600 watts of mains power which will run a fantastic array of appliances. It would be ideally suited to running power tools, lighting (including fluros) electric motors and much more. A must for farming, camping, mining, boating , remote settlements and wherever else 240V power isn't available. S/C SEPTEMBER '91 This compact digital altimeter can . display altitude up to 19,990 feet with 10ft resolution . It has a barametric pressure offset adjustment for . heights up to 5000 feet and 1s ideal for use in ultralights, gliders, hanggliders and balloons. 2sao $299.oo LED Digital Tachom ter K S/ C AUGUST '91 ase Not Included Have you ever wondered how many revs your car's engine is doing at 100km/ h or at any speed for that matter? This digital tachometer will tell you . It works with all ignitions from Kettering to Hall Effect systems and with 4, 6 and 8 cylinder cars . K6770 Kit Veralon $499 .00 $625 .00 K 6775 Fully Built $625 & Teated 24V Input .00 K 6774 Fully Built & T eated 12V Input 300 Watt Inverter with Auto Start ~t"' tJSt\. $279 K 6755 Fully Built and Te■ted $379 .00 K 6705 Kit ...=-- $~o Thla Month $32.50 Casio Printing Calculator Bargain 6 Mic & 2 Au x Inputs witn Canon Sockets. Trebl~. Bass & Master Controls. $1'9'.95 $99.oo $399.oo 10 Watt Megaphone A2051 High Performance Wireless Microphone Incorporates ALC circuitry (Automatic Level Control) which helps eliminates distortion caused when input levels are too high . Can be received on any FM radio. Very professional mic. Built-in Antenna . C 0328 $129.so • Black print and red print for subtractions • Sub-total/ total • Item counting • Average function • 3 digit comma markers • Full decimal system. Operates on 4x AA batteries (included) or power supply (not included). Includes one roll of 58mm paper and dust cover. $99.oo 8 Channel Audio Mixer Multimeter X 2125 Normally 40 Watt Inverter EA Aug '85 This inverter is ideally suited for powering low wattage mains appliances from the car battery whi le camping . Typically, it can be used to power an electric shaver, electric blanket , electric can opener or a 40W light bulb. Credit Card Thla Month o"to EA Aprll '68 • Super Compact - kit is supplied in Altronics H 0482 tough ABS case • Uses High Efficiency Toroid Transformer thus keeping down heat dissipation , battery drain and weight • Auto start draws power from your battery only when appliance is plugged in and " turned on" i.e. battery can be left permanently connected if req • Voltage regulated • Current regulated • Current overload unit self limits Single PC Board construction • easy to build as there is very little internal wirinQ . K 6750 Kit Veralon .00 K4320$31.oo Q 1060 Normally $399.oo Powerhouse 600W K 5815 Fantastic for the glovebox, toolkit and, of course, your top pocket. Excellent for mobile field work . A great gift idea for your budding genius student. K 5020 Normally $~.OO Thla Month Range: 300M approx. Requires 8 x AA cells (not supplied) . Includes electronic whistle activated by button in the handle. $µg'.95 $99 High Quality Microphone A 1980 I.Jaea the femoua Shure SM 58 In Assembled in Taiwan, however in our humble estimation sounds every bit good as the American assembled product. Fantastic value at this price. Harris Four Channel Digital R Thi ■ remarkable product can be almply ■witch aelect programmed to LITERALLY DOZENS OF APPL/CA T/ONSI The Harris A 2100 provides 4 channels of natural speech recording and play-back. Recording time for each channel is internally selectable to 10, 15, 20 or 30 seconds. The sound quality is outstanding on the lower settings and " industrial " on the higher ranges. Channels can be used separately or linked to provide one long recording/ announcement. u100$799.oo Toroid Power Transformers We've Reduced Our Prlcea 20% This Month! Why • Torlod? • Smaller size and weight to meet modern "Sli mline" requirements •Low electrically induced noise demanded by compact equipment • High efficiency enabling conservative rating whilst maintaining size advantages • Lower operating temperature • Simple, quick single bolt mounting $gk.e5$4O SEC SEC Sec. V Currant A Current B 12+12 18+18 25+25 30+30 35+35 6.6 4.4 3.2 2.6 2.2 3.3 2.2 1.6 1.3 1.1 •'SEC SEC Sec. V Current A Current B 25.0 16.67 12.0 10.0 8.57 -7.5 6.67 12.5 8.33 6.0 5.0 4.29 3.75 3.33 Telecom Type Line Isolating Transformer M 1000 Normally $ j.3".s5 ()o\o Now $11.oo s►~~ '1) Cat. No M 3050 M 3055 M 3080 M 3065 M 3070 M 3075 M 3080 SEC SEC Sec. V Current A Current B 12+12 18+18 25+25 30+30 35+35 40+40 45+45 13.3 8.9 6.4 5.3 4.6 4.0 3.56 Cat. No M 3120 M 3125 M 3130 M 3135 M 3140 M 3145 M 3150 M 3155 16.6 14.2 12.5 11.1 10.0 9.0 8.3 7.6 30CFM Air Flow 80mm x 80mm x 32mm WHY PAY $400 OR MORE FOR A DAVID CLARK SET? • High performance , noise attenuating earphones. • Noise cancelling microphone • Cushioned head pad •Super 80 CFM Air Flow 120 x 120 x 38mm F 1030 $_32:95 $ 2 0 24VDC Brushless Model FF ERING TOO OLP Ideal for the service technician and hobbyist alike. This lightweight de-soldering iron allows components to be quickly and cleanly removed with one hand . Naturally it's SEC approved and comes with a cleaning wand. Can be used as a soldering iron . T 1250 S59'.es Thla Month $49.95 Micron Soldering Station 8.3 7.1 6.2 5.5 5.0 4.5 4.10 3.8 Superb , professional pilot's headset will last a lifetime with reasonable treatment • Includes standard aircraft jacks. Multi purpose T 2440 Normally $ ~ . 9 5 1OOVA Thi• Month $14O.oo MK II Replacement Tips Transformer Another quality transformer from Altronics. Wound on expensive grain oriented steel. c 9070 Only $189.oo HALF PRICE I 12V 15V 24V Tool ~--- -- -- -~-;~pSELLIN~ The MICRON T 2440 soldering station offers the ultimate in controlled temperature hand soldering. Temperature range is switch selected. So there is no need to change soldering iron tip. • Zero Voltage Switching • Grounded Tip • Low Voltage Element • Chrome Plated Iron Clad Tip A11$5.5oea T 2427 0.8mm T 2428 1.6mm T 2429 3.2mm Dalo Pens Primary: 240V Secondary Breadboards 8.3A 6.6A 4.1A . T0033~5$4 • Standard 0.1 inch spacings • Accepts all LSl's semis, transistors, diodes, leds and passives ~b~ ~~: ~ P 1000 100 Holes $3.25 MA 2110 $_28'.'e5 P 1005 640 Holes $12.so Thla Month Only $ 1 5 .00 P 1007 640 & 100 Holea $14.so 'D' Series Computer Connectors. P 3000 P 3010 P 3020 P 3030 P 3040 P 3050 P 3090 P 3100 P 3110 P 3120 P 3130 P 3140 P 3150 P 3190 P 3200 P 3210 P 3220 P 3230 P 3240 P 3250 P 3290 Aviation Headset Impedance: 600 Ohm line/ 600 Ohm equipment. 240V Models F 1040 $,e'.e5 $ 2 0 T 2446 $49.e5 Multiple De-Soldering sturdy • Great performance• SEC SEC Sec. V Current A Current B 30+30 35+35 40~40 45+45 50+50 55+55 60+60 65+65 NEW MODEL NOW INCORPERATES JAPANESE CERAMIC CARTRIDGE I May be used to provide isolation between Telecom Australia lines and mains operated equipment. Telecom approved to specifications 1053 and 1054. Huge Savings on Computer Fans 120mm x 120mm x 38mm 6.7 4.45 3.2 2.7 2.3 2.0 1.78 500VA $129'.oo $ 9 9 $.89'.e5 $ 7 2 12+12 18+18 25+25 30+30 35+35 40+40 45+45 160VA $,i5'.oo$5O Variable Temperature Soldering Iron DB9 Male 9 pin connector DB9 Female 9 pin connector DB9 Male rt/I PCB connector DB9 Female rt/I PCB connector DB9 Male straight PCB connector DB9 Female straight PCB connector DB9 Backshell cover DB15 Male 15 pin connector DB15 Female 15 pin connector DB15 Male rt/I PCB connector DB15 Female rVI PCB connector DB15 Male straight PCB connector DB15 Female straight PCB connector DB 15 Backs hell cover DB25 Male 25 pin connector DB25 Female 25 pin connector DB25 Male rt/I PCB connector DB25 Female rt/I PCB connector DB25 Male straight PCB connector DB25 Female straight PCB connector DB25 Backshell cover P 1012 400 & 1280 Holes $44.60 P 1015 500 & 1920 Holea $65.oo Metal backing plate for shielding of sensitive circuitry. NOW 10 Up $1.55 $1.60 $3.40 $2.20 $2.50 $3.40 $1.50 $1.95 $2.40 $3.95 $4.40 $4.40 $2.70 $1.90 $3.10 $3.30 $4.40 $4.40 $3.90 $5.50 $2.05 $1.35 $1.40 $3.00 $1.95 $2.35 $3.00 $1.35 $1.65 $1.70 $3.75 $3.75 $3.75 $2.50 $1.75 $2.25 $2.50 $3.95 $3.50 $3.50 $5.25 $1.85 ow there's no need to pay $10 more for a circuit breaker. ltronics product is USA nderwriters Laboratories listed nd that speaks for itself) and ce again is an Altronics Price eakthrough. 5503 3 Amp All 05 5 Am MU Metal Shielded Audio Transformers Microphone Type Primary: 200 Ohm Secondary: SOK Ohm M 0101 $;M".e5 $ 2 5 Brldglng/ laolatlng Type Use for coupling ·audio modules. • ~ Nominal impedance ratio 10K: 10K · (1:1) M 0702 $~95 $ 2 5 Featurw■ : • Raw aluminium, black or natural anodised finish • These beautifully crafted rack cabinet boxes will give your equipment a really 1st class appearance • Aluminium construction with removable top and bottom steel cover panels • All dimensions conforms to the International Standard • Ventilated lid • Deluxe finish front panel • Individually cartoned • Supplied in Flat Pack Form - Easily assembled in minutes. c Australian Designed and , Manufactured Professional Series:\ Modular Rack Frames i· Suitable for home or commercial use , these fantastic rack frames are durable strong, good looking , light weight and easy to assemble.. . The frames are available on either Natural Anodised aluminium or Black Powder Coat aluminium and the side panels in Electric Blue or Black Powder Coat finish . Ideal for use in home Hi-Ii systems, Professional Audio installations, Band Gigs, Computer Patch panel etc. H H H H H H H H H H H H 5204 5205 5208 5207 5212 5213 5218 5219 5230 5231 5238 5238 Now $125 Rack frame 4U Nat. Panel set for H 5204 Rack frame 6U Nat. Panel set for H 5206 Rack frame 12U Nat. Panel set for H 5212 Rack frame 18U Nat. Panel set for H 5218 Rack frame 30U Nat. Panel set for H 5230 Rack frame 38U Nat. Panel set for H 5238 $44 $135 $49 $152 $80 $170 $ff $205 $143 $242 $175 H 5304 H 5305 H 5306 H 5307 H 5312 H 5313 H 5318 H 5319 H 5330 H 5331 H 5338 H 5339 k J· ,i (:=:: w· Rack frame 4U Black Panel set for H 5304 Rack frame 6U Black Panel set for H 5306 Rack frame 12U Black Panel set for H 5312 Rack frame 18U Black Panel set for H 5318 Rack frame 30U Black Panel set for H 5330 Rack frame 38U Black Panel set for H 5338 Enables rack mounting of tuners, videos, C.D. players, $44 amplifiers etc. $135 which normally $49 can't be rack $152 mounted . $80 · Supplied in flat $170 pack form $99 · easily $205 assembled in $143 minutes. $242 Available in $175 black only. Now $125 STOP PRESS - NOW AVAILABLE IN 2 6 4 UNIT SIZES I H 5352 2 Unit (88mm) $49.95 H 5353 3 Unit (132mm) $49.95 H 5354 4 Unit (176mm) $55.95 Great Value Altronics Kits Universal High Power Amplifier Module K514o$69.oo Sub-Woofer Adaptor Get an amazing bass improvement from your stereo system . This fantastic adaptor simply "samples" your stereo amp output and provides a single channel output to feed a separate sub•woofer amp. Kssao$29.95 M 9020 12V AC Adaptor To Su it $16.95 Beat Triggered Strobe Add Some Ute To Your Next Party Flashes in time to your music. Will also work as normal strobe. K 5790 $79.es K 5795 Two Tube Option $16.50 All components, including output transistors mount on a single PCB . Suitable for high quality guitar amp, public address or in a high fidelity stereo amplifier. Kit includes angled heats,nk bracket , main heatsink and unlike other kit suppliers, the in-built Polyswitch for loudspeaker protection. • Speech Synthesizer Herw la a Hlf contained Spffch Synthellzer that doe• not rwqulre a computer to control It. It can be connected to almost any appliance, vehicle or home remote control system to let you know when the kettle has switched off, the doors are locked or the water in the radiator is boiling. Blank Eprom included . $_9ho K 9500 Thla Month Only $ 85.oo K 9502 Prw-Programmed Eprom $20.oo This project will sense a door opening in a large or small room and will sound a two•tone chime. It does not have to be anywhere near the doorway as it uses an ingenious sensor to detect the pressure change caused when the door opens. K 1915 $J.5,:fo Thi• Month $29.oo Playmaster Pro Series 1 Power Amplifier Module Fantastic for use in Juke boxes, amplifier racks (multi -amplifier setups) discos etc. K 5170 $85.oo 174 Roe St. PERTH W.A. 6000 Phone (09) 328 2199 PAONE ORDER TOLL FREE 0OS 999 007 MAIL ORDER C/ - P.O. Box 8350 Perth Stirling St. W.A. 6849 HEAVY HEAVY SERVICE - All orders of 10Kgs or more must travel Express Road Please all~w 7 days for delivery. $12.00 to 10Kgs. $15.00 over 10Kgs. INSURANCE - As with virtually every other Australian supplier, we send goods at consignees risk . Should you require comprehensive insurance cover against loss or damage please add $1.00 per $100 of order value (minimum charge $1) . When phone ordering please request " Insurance" . TOLL FREE PHONE OFIDER - Bankcard, Visa. Mastercard Holders can phone order toll free up to 6pm Eastern Standard Time. Remember with our Overnight JetHrvlce we deliver next day. STANDARD DELIVERY 6 PACKING CHARGE $5 50 to 1Kg, $81Kg-5Kg AUSTRALIA WIDE - Via Austraha Post allow approx 7 days for delivery OVERNIGHT JETSERVICE Up to 3Kg Is $10 00, 3Kg to 5Kg ,s $28 00 Overnight JelHrvtce Courier for dehvery next day Country areas please allow addItIonal 24-48 hours AL TRONICS RESELLERS- Chances are there is an Altronic Reseller right near you - check this list or phone us for details of the nearest dealer. Blue Ribbon DHlara are highlighted with a ■ These dealers generally carry a comprehensive range of Altronic produc~ and kits or we'll order any required item for you . WA COUNTRY ALBANY BP Electronics ■ (098) 412681 Micro Electronics (098) 412077 BUNBURY Micro Electronics (097) 216222 ESPERANCE Esperance Commun ications (090) 713344 KALGOORLIE Todays Electronics ■ (090) 215212 MANDURAH Lance Rock Retravision (09) 535 1246 Micro Electronics (09) 5812206 PORT HEOLAND Ivan Tomek Electronics (091) 732531 ROCKINGHAM TV Joe's (09) 5271806 NT ALICE SPRINGS Farmer Electronics (089) 522388 DARWIN Ventronics (089) 853 622 VIC AII Electronic Components (03) 6623506 The Electronic Component Shop ■ (03) 6706474 BORONIA Ray Cross E:ectronics ■ (03) 7622422 CHELTENHAM Talking Electron ics (03) 5842386 CROYDON Truscott Electronics ■ (03) 7233860 PRESTON Preston Electronics ■ (03) 4840191 COUNTRY BAIRNSDALE LH & LM Crawford (051 ) 525677 BALLARAT Ballarat Electronics (053) 311947 BENDIGO KC Johnson ■ (054) 411111 MILDURA McWilliam Electronics (050) 236410 QLD Delsound PL ■ (07) 8396155 NEWSTEAD ECO Electronics (07) 2541153 WEST END B.A.S. Audiotronics (07) 8447566 WOODRIDGE David Hall Electronics ■ (07) 8082777 MAROOCHYDORE MALS Elec.tronics ■ (074) 436119 MARYBOROUGH Keller Electronics (071) 214559 PIALBA Keller Elect,onics (071) 283749 ROCKHAMPTON Access Electronics (East St.) (079) 221058 TOWNSVILLE Super Solex ■ (077) 724466 SA Force Electronics ■ (08) 2125505 BRIGHTON Force Electron ics ■ (08) 3770512 CHRISTIES BEACH Force Electronics ■ (08) 3823366 FINDON Force Electronics ■ (08) 3471188 HOLDEN HILL Force Elect:·onics ■ (08) 2617088 LONSDALE Force Electronics ■ (08) 3260901 ENFIELD Aztronics ■ (08) 3496340 COUNTRY WHY ALLA Eyre Electronics (086) 454764 TAS HOBART George Harvey ■ (002) 342233 LAUNCESTON George Harvey ■ (003) 316533 NSW David Reid Electronics ■ (02) 2671385 SOUTH Sheridan Electronics (02) 2817727 SMITHFIELD Chantronics (02) 6097218 COUNTRY COFFS HARBOUR Coifs Habour Electronics (066) 525684 NEWCASTLE Novocastrian Elect.Supplies (049) 621358 WARNERS BAY Vilec Distributors (049) 489405 WINDSOR M & E Elect . and Communications (045) 775935 WOLLONGONG Newlek Electronics ■ (042) 271620. ALTIMETER Muftipfy aJt, by 10 t.or hetght in feet Digital altimeter for gliders & ultralights, Pt.3 This final article on the Digital Altimeter gives the full construction & calibration details. We also detail a simple 9V regulator circuit so that you can use the instrument with an external 12V supply. ost of the assembly work for the Digital Altimeter involves installing the parts on the three PC boards. These a.re the sensor/amplifier board (code SC04108911); the display driver board (code SC041 08912); and the display board (code SC04108913). Before mounting any of the parts, it's a good idea to spend a few min- M By JOHN CLARKE 32 SILICON CHIP utes checking your etched boards against the published patterns. If you do find any defects, repair them now as they will be much harder to track down once- the components are in position. Now check that the holes sizes in the PC boards are correct. The four corner mounting holes on the two large boards should all be drilled to 3mm, as should the two sensor mounting holes on the sensor/ amplifier board. The display board requires 5mm holes for the two toggle switches (S1 & S2), a 3mm hole for LED 1, and a 12mm hole for potentiometer VR6. The SC04108911 and SC04108913 boards must also each have two corners cut off, so that they will fit inside the case (see Fig.9). If the boards are not supplied ready cut, trim them now using a hacksaw and file the edges to a smooth finish. This done, check that the small display board is no wider than 39.5mm. You may need to file the top and bottom edges to achieve this but make sure that you do not file away any of the adjacent tracks. Sensor/amplifier board You can now begin the assembly by installing the parts on the sensor/ amplifier board (SC04108911). Fig.9 shows the parts layout and wiring details. Install the wire links first, then install PC stakes at the TP and GND locations (five in all). Keep the links as straight as possible. If necessary, straighten the link wire by clamping one end in a vyce and then pulling on the other end with a pair of pliers so that it stretches slightly. The resistors are the next to go in. These are all 1 % types and colour codes for all the values are listed in Table 2. We also recommend that you check each resistor with your digital multimeter before installing it on the board, as it's easy to confuse some of the colours. The trim pots and resistor arrays (R1, R2, R4 & R5) can also be installed at this stage. Note that R1 & R5 are 22kQ an::ays, while R2 & R4 are 100kQ types. You will find the value printed in code on the side of the component see Table 3. The r()sistor arrays can be inserted either way around but be sure to orient the trimpots with the screw adjustments as indicated on Fig.9. Next, the ICs and capacitors can be mounted in position. Check each IC part number carefully before installing it on the board and make sure that all ICs are correctly oriented. Similarly, take care with the orientation of the tantalum and electrolytic capacitors. Note that six of the 0.1µF capacitors are monolithic types. These are small bead-like components carrying the code number "104" and they can be mounted either way around. The remaining 0.1µF capacitors are rectangular in shape (code 100n) and again can be mounted with either polarity. The LP2950 3-terminal regulator can now be installed, along with transistors Q1 & Q2. Bend Ql 's leads so that the body of the transistor lies flat against the PC board, as shown in Fig.9. Q2 is mounted with its metal tab towards the sensor. Fig.3 in the previous issue shows the device pinouts. The pressure sensor is mounted by first soldering its pins to the PC board. Additional support for the sensor is then provided by bolting it to a plastic right-angle bracket. To mount the bracket, first mark out its mounting holes from underneath the board, then drill two holes to accept 4BA screws. This done, temporarily bolt the bracket in position and mark the sensor mounting holes (use a thin pencil or a metal scribe). Finally, remove the bracket, drill the sensor mounting holes and install the bracket in position. I r a.,11 -~',,~\l ~~VK~ 2_ -:,.,...;;_ -:_ ..._-_-_-_-_ - ~ L ~,.,,_ 01,_S_ _, ll1 " ~ P2950 · . u,F----- - - - - - ~ - - ' Fig.9: install the parts on the three PC boards as shown in this wiring diagram. Make sure that all polarised parts (including the ICs) are correctly oriented & note that 1 % metal film resistors are used throughout to ensure accuracy. Use 25mm-long 4BA nylon screws and nuts to secure the sensor to the bracket. This will ensure minimal stress with changes in temperature. Tighten the screws firmly, then use a sharp utility knife to trim the nylon screws to length, to give a neat finish. Similarly, trim the bracket-mounting screws so that they extend no more than 3mm below the lower edge of the PC board. Display driver board The assembly procedure for this board (SC04108912) is similar to that outlined for the first board. As before, install the PC stakes and wire links first, then install the remaining parts as shown on Fig.9. You will need to install PC stakes at the GND and TP5TP8 locations, and at the three external wiring points right at the top of the board. Note that ZD1 and diode D1 face in opposite directions to each other. Be careful not to confuse these two components and make sure that they are oriented correctly. The battery holder requires a minor amount of surgery before it is installed. As supplied, it has standoffs on its base and these must be trimmed off so that the base is flat - otherwise the battery will later foul components on the sensor/amplifier board. These standoffs can easily be removed using a sharp utility knife. Once this has been done, secure the NOVEMBER 1991 33 This inside view shows how the pressure sensor (top, left) is secured to a rightangle bracket using nylon screws. The battery holder is mounted directly on one of the boards but can be replaced with the optional 9V regulator board if you wish to power the unit from an external 12V supply. battery holder to the board using three 2mm x 5mm-long screws and nuts. Don't forget to solder the two leads from the battery holder to their respective copper pads. Display board Apart from the LCD, this board carries relatively few components but it must be assembled in strict order to avoid problems. Begin by installing all the wire links. Once these are in, trim their leads short on the solder side of the board so that they cannot later foul the back of the LCD. The next step is to connect the three 8-way A, B & C bus leads. These bus leads are cut from a 200mm-length of 0.1-inch spacing rainbow cable, as specified in the parts list. Cut the cable so that the A-bus is 60mm long, the B-bus is 65mm long and the C-bus is 75mm long. This done, remove about 2mm of insulation from each of the leads and solder the three cables to the board. 34 SILICON CHIP At this stage, we suggest that you check the display board carefully for any defects. The LCD is mounted on the copper side of the board and once it is in position, it will be very difficult to locate and correct any faults. In particular, check for bad or missed solder joints and for shorts between adjacent tracks. When you are satisfied that everything is OK, the LCD can be installed. To do this, you first have to check its orientation by looking at the digits in strong light. If you position the display so that it reflects the light directly back to you, the digits should be just discernible. Orient the display so that the decimal points are at the bottom (minus sign & "1" digit to the left), then install it on the copper side of the board with the hole for VR6 to the right. Finally, check that the display sits evenly on the board, with its face 4mm above the board surface. The display pins can then be soldered us- ing a fine-tipped soldering iron. The display board assembly can now be completed by installing the two switches (S1 & S2) and the LED. Both switches are secured using a star washer and nut. Note that S1 is the 3position centre-off unit. The leads of the LED pass through the hole between the two switches and are soldered directly to the switch terminals. Position the LED so that its top surface sits about 7mm above the board, so that it will later protrude through the front panel. Its cathode (K) lead is the shorter of the two and is soldered directly to the adjacent S2 terminal. The anode lead is extended using tinned copper wire so that it reaches the far terminal of S 1. Wiring Start the wiring by connecting the three 8-way cables (A, B & C) from the display board to the driver board. Note that the A and C-bus cables cross over each other in order to reach their respective wiring points on the driver board, so connect these wires first before connecting the B-bus wiring. Using The Digital Altimeter With An External 12V Supply This simple add-on regulator circuit will allow the Digital Altimeter to be powered from an external 12V battery (eg, from an existing battery fitted to the aircraft). Because the altimeter draws only about 10mA, its affect on an external 12V battery will be negligible. The changes required involve completely removing the 9V battery holder and replacing it with a small PC board which holds all the necessary circuitry. In addition, a 2.1 mm DC power socket is mounted on the rear panel of the altimeter. How it works The circuit is quite simple and uses just a handful of components. Diode D1 provides reverse polarity protection, while the 100Q resistor provides series limiting resistance for 16V zener diode ZD1 which is included for overvoltage and transient protection. This resistor also provides a voltage drop of 1V due to the 10mA current drawn by the altimeter. Zener diode ZD2 drops the incoming supply voltage by a further 3.3V to provide the nominal +9V supply for the altimeter circuit. The 100µF capacitor across this section of the supply is for decoupling purposes. In use, the supply is designed to cope with voltages ranging from 14.4V (battery fully charged) down I TO PANEL SOCKET + I The "1" for each bus designates the orientation required. Next, the two switches can be wired as shown on Fig. 9, using a short length of6-way cable. This done, cut a 75mm length of 3-way cable and connect it between VR6 and the relevant wiring points on the display driver board. VR6 can now be temporarily secured to the display board using several fibre washers and a nut. DC PANEL SOCKET 01 1N4002 100 25VWI EXTERNAL 12V SUPPLY FOR ALTIMETER Fig.to: the regulator circuit uses D1 for reverse polarity protection, while ZD2 & the 100Q resistor reduce the supply voltage by about 4.3V to give a nominal +9V output. ZD1 provides overvoltage & transient protection. to + 12V (battery flat). When the input voltage is 14.4V, the regulator output will be 9.4V due to the 0.7V drop across D1, the 1V drop across the 100Q resistor and the 3.3V drop across ZD2. When the input voltage is + 12V, the output will be +7.0V. PARTS LIST 1 2.1 mm DC panel socket 1 2.1 mm DC line plug 2 100mm lengths of hookup wire 3 transistor insulating bushes 1 1N4002 1A diode, D1 1 16V 1W zener diode, ZD1 1 3.3V 1W zener diode, ZD2 1 10OQ 0.5W resistor 1 100µF 16VW PC electrolY1ic capacitor Miscellaneous Three screws and nuts to secure PC board; two screws and nuts to secure panel socket. Fig.11: parts layout for the regulator board. It mounts in the battery holder position. Finally, the sensor/amplifier board and the display driver board are wired together using an 80mm-length of 6way cable. Case preparation A plastic case measuring 140 x 110 x 46mm accommodates all the circuitry for the altimeter. This case features aluminium front and rear panels and requires only a small amount This 9.4-7.0V range is well within the operating range of the altimeter. Construction The regulator circuit is built on a small PC board coded SC04108914 and measuring 52 x 30mm. Fig.11 shows the parts layout. Take care with component orientation and install ZD2 with a loop in one of its leads to provide thermal stress relief (see photo). The two output pads should each have a short length of tinned copper wire soldered to them, such that the wire protrudes from the copper side of the board. These leads can then subsequently be inserted into the holes originally provided for the battery holder. The input supply leads can be run with 2-way rainbow cable and should be made about 100mm long. These are connected to the 2.1 mm DC panel socket on the rear panel. The regulator board is mounted on the display driver board using the three mounting points originally allocated for the battery holder. Use short plastic spacers (eg, transistor insulating bushes) under each mounting point and secure the board using screws and nuts. of work to accept the hardware. Both halves of the case have six integral plastic standoffs but only the four corner standoffs are needed. The two centre standoffs must be removed from the case halves to provide clearance for the PC boards and this is best done using an oversize drill bit. When the standoffs have been removed, mark out the front panel using the label as a template and drill NOVEMBER 1991 35 TABLE 2: RESISTOR COLOUR CODES 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 No. Value 5-Band Code 1 1 1 1 1 4 1 1 2 1 2 1 2 1 1 2 2 1 2 2 1 1 4 2 1 1 1MO 470k0 360k0 200k0 160k0 100k0 75k0 51k0 47k0 27k0 20k0 13k0 10k0 3.3k0 1.2k0 1k0 3300 3000 2700 2400 2200 2000 1600 1500 1000 240 brown black black yellow brown yellow violet black orange brown orange blue black orange brown red black black orange brown brown blue black orange brown brown black black orange brown violet green black red brown green brown black red brown yellow violet black red brown red violet black red brown red black black red brown brown orange black red brown brown black black red brown orange orange black brown brown brown red black brown brown brown black black brown brown orange orange black black brown orange black black black brown red violet black black brown red yellow black black brown red red black black brown red black black black brown brown blue black black brown brown green black black brown brown black black black brown red yellow black black black holes to accept the switches (6mm), LED (3mm) and potentiometer (9mm). The display cutout is a 45 x 18mm rectangle which sits 24mm in from the lefthand edge of the panel and 11mm down from the top. It can be made by first drilling a series of small holes around the inside perimeter, then knocking out the centre piece and filing the edges so that the Perspex window is a tight fit. Once this job is done, remove the Perspex window and trim the label so that it measures 98 x 36mm (this will allow the edges of the label to clear the locating slots for the front panel). The label can then be carefully affixed to the front panel and the holes cut out with a utility knife and reamer. Testing Now for the big test. Check your work carefully, then install the battery and switch on. If everything is OK, you should immediately get a reading on the display and you should be able to alter this reading by rotat36 SILICON CHIP ing the BAR ADJ control. Check that this is so, then check the supply voltages to the ICs. You should get +9V on pin 7 of ICs1-6 & IC11, pin 16 ofIC12 & pin 1 ofIC13; and +SV on pin 20 ofIC7, pin 14 ofIC8 & pin 16 ofICs9-10. If any of these voltages are incorrect, switch off and locate the source of the problem before proceeding further. Assuming everything checks OK so far, switch S1 to the BAT position and check that the LED lights to indicate the battery condition. If the LED doesn't light, it's probably installed the wrong way around (or the battery is flat) . Initial setting up Before the altimeter can be calibrated, adjustments must be made to trimpots VR1, VR4 & VRS. You will need a multimeter for these adjustments. (1) The first step is to adjust VR1 so that the 6V reference gives an output of 6V. To do this, connect your meter between GND and TP1 and adjust VR1 until the reading on your meter shows 6.0V (anywhere from 5.99-6.0lV is OK) . Once set, this 6V reference voltage on TP1 will fix the voltages on TP2, TP3, TP6 & TP7 at 1.25V, 2.0V, 3.0V & 2.0V respectively. Check that these voltages are correct - they should all be within 30mV (ie, ±0.03V) of their nominal value. (2) This step involves adjusting VR4 to give a display offset reading of 1013 when the unit is in barometer mode. Select the BAR display mode, connect your multimeter (set to read DC millivolts) between TP7 and TP8, and adjust the BAR ADJ control for a reading of 0.00mV. This done, adjust VR4 so that the display show:s 1013hPa. (3) VRS is used to calibrate the barometer offset control. First, adjust VR2 so that the altitude reads 000 when the barometer is set to 1013hPa. The following table is a modified section of the altitude vs pressure curve published in Pt.1. It shows the altitude reading for a particular barometer setting when compared to the reference of 1013hPa. Note that the altitude sign is minus for pressures below 1013hPa because we want the barometer adjust control to subtract from the altitude reading. Altitude Reading 1000 0000 -1000 -2000 -3000 -4000 -5000 Barometer Reading 1051 1013 977 942 907 875 843 The calibration procedure involves using the BAR ADJ control to obtain the barometric values listed in the above table and then checking the corresponding altitude readings. Rotate VRS clockwise if the altitude readings are higher than required and anticlockwise if the altitude readings are lower than required. Note: re-check the calibration after each adjustment ofVRS. Final assembly To ensure minimum temperature drift, the case is lined with 2mmthick polyurethane sheeting. This is secured to the front and rear panels using contact adhesive, with an appropriate cutout for the display win- dow. The two larger pieces for the base and lid are simply sandwiched between the case and the PCBs. The front panel is supported on the display board by the switches and the potentiometer. Each switch should be fitted with two nuts between the board and the front panel to achieve the correct spacing, while the threaded potentiometer collar should be fitted with five fibre washers. The panel is then placed in position and secured using a nut for the potentiometer and dress nuts for the two switches. The entire assembly can now be fitted inside the case and the two large boards secured to the integral standoffs using self-tapping screws (the sensor/amplifier board goes on the lid). Note that you wilrhave to drill a hole in the rear panel that lines up with the B (open) port of the pressure sensor (the A port is sealed) . Fit this hole with a rubber grommet to provide a seal against any external tubing that may subsequently be fitted. This close-up view shows how the optional regulator board & its associated DC socket are installed. The regulator board mounts on the display driver board in the position normally reserved for the battery holder. Final calibration The final calibration procedure involves setting VR2 (OFFSET ADJUST) and VR3 (SPAN) so that the altimeter displays the correct readings. To do this, you will need access to a calibration rig or to a commercial altimeter of known accuracy. Ideally, the offset adjustment (VR2) is made at sea level, so that the span adjustment (VR3) is completely independent of this setting. This simply TABLE 3: Sil RESISTORS & TRIMPOT CODES EIA Code 104 Value 100kQ 22kQ 10kQ 5kQ 223 103 502 CAPACITOR CODES Value IEC Code EIA Code 0.47µF 0.22µF 0.1µF 0.047µF 0.01µF 220pF 100pF 470n 220n 100n 47n 10n n22 n10 474 224 104 473 103 221 101 The inside of the case is lined with 2mm-thick polyurethane sheeting to provide thermal insulation. Note the rubber grommet fitted to the hole in the rear panel that provides access to the open port of the sensor. involves setting the instrument to the local barometric pressure and adjusting VRZ for a reading of 000 feet. If the offset cannot be done at sea level, then the two adjustments will interact. In this case, adjust VRZ to give a reading of 000 on the ground for the local air pressure. The altimeter should then be "flown" to a suitable altitude and VR3 adjusted to obtain a reading that matches the commercial unit in the aircraft (note: make sure that both altimeters are set to the same barometric pressure). Because the two adjustments inter- act to some extent, this process may have to be repeated several times until the unit reads correctly. Alternatively, you can calibrate the instrument using the pressure chamber setup described in Pt.1. Finally, the formula for the height vs. pressure curve given on page 30 in the September 1990 issue is incorrect. The correct formula is: p = 1013.25 (1 - 6.875 X 10- 6 X Height)5.2563 Table 1 and the curve plotted in Fig.1 are correct. SC NOVEMBER 1991 37 RITRON QUALITY RITRON RITRON ADD PRICE TO BASE SYSTEM COST. 512K VGA CARD ...................... $50 IM VGA CARD ......................... $100 TO CHANGE A 40M HARD DRIVE TO A 85M HD add ........................ $150 126M HD add .......................... $290 200m HD add ...................... ... $700 EXTRA RAM 1 MEG add ........................... $90 2 MEG add ........................... $180 ~ !•!• • g §•§ ;l•• 2 •1• • • • ·• w 80286-16 CPU 1 MEG RAM EXPANDABLE TO 4 MEG 21 Mhz LANDMARK SPEED TEST 1.2M JAPANESE BRAND F.D.D 42M HARD DISK DRIVE 28ms ACCESS 101 EXTENDED '"CLICK'" KEYBOARD J APANESE KEYBOARD SWITCHES MINI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 Res) 2 SERI AL, PARALLEL, GAME PORTS 3 YEAR '" AUSTRALI AN .. PARTS & LABOUR WARRANTY 256K VGA CARD. IBM• COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE 80286-12 CPU 1 MEG RAM EXPANDABLE TO 4 MEG 16W,z LANDMARK SPEED TEST 1.2M JAPANESE BRAND F.D.D 42M HARD DISK DRIVE 28ma ACCESS 101 EXTENDED '"CLICK'" KEYBOARD JAPANESE KEYBOARD SWITCHES MNI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 res) SERIAL, PARALLEL, GAME PORT 3 YEAR '"AUSTRALIAN'" PARTS & LABOUR WARRANTY 256K VGA CARD. IBM• COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE SOFTWAREINCLUDED. ASSEMBLED & TESTED IN AUSTRALIA $1 , 339 $1,199 SOFTWARE INCLUDED. ASSEMBLED & TESTED IN AUS TRALIA TAX INC. TAX EX $1 ' 399 <at>· 386l5Z $1 699 ' TAX INC. $1,495 TAX EX •SHAREWARE SOFTWARE ASSEMBLED & TESTED IN AUSTRALIA. EXECUTIVE ( •· 4·~§t~§·· · ·, 80486SX-20 CPU 64K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 32 MEG 75Mhz LANDMARK SPEED TEST 85 MEG HARD DISK 18ma ACCESS TI ME 1.2M JAPANESE BRAND F.D.D 101 EXTENDED '"CLICK'" KEYBOARD SERIAL, PARALLEL, GAMES PORTS, 1MEG VGA CARD SUPA VGA COLOUR MONITOR (1024 x 768 Resolution) MINI CASE & 200W POWER SUPPLY 3 YEAR '"AUSTRALIAN'" PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. •SHAREWARE SOFTWARE ASSEMBLED & TESTED IN AUSTRALIA. TAX WITH 200 MEG DRIVE ' $2,395 INC. TAX EX. EXECUTIVE ~x~ss-~s>) 0 80386-40 CPU 128K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 16 MEG 650Mhz LAN DMARK SPEED TEST 126 MEG HARD DISK 12ma ACC ESS TIME 1.2M JAPANESE BRAND F.D.D 101 EXTENDED '"CLICK·• KEYBOARD SERIAL, PARALLEL, GAMES PORTS 512K VGA CARD SUPA VGA COLOUR MONITOR (1024 x 768 Resolution) MINI CASE & 200W POWER SUPPLY 3 YEAR '"AUSTRALIAN'" PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. 'SHAREWARE SOFTWARE $2 ' 095 ASSEMBLED & TESTED IN AUSTRALIA. TAX INC. $1,895 TAX EX $ 3,Q95TAX EX. $2,595 TAX EX. ' ROD IRVING ELECTRONI Est. 1977. MAIL ORDER HOTLINE: 008 33 57 57. (ORDERS ONLY) E NQUIR ES: (03) 543 78TT HEAD OFFICE: 56 RENVER RD, CLAYTON . PH: (03) 543 2 166. FAX (03) 543 2648 CITY 48 A'BECKETT ST. MELBOURNE . PH. 663 6351 / 639 1640. FAX: 639 1641. NORTHCOTE 425 HIGH ST. NORTHCOTE, PH. 489 8866 . FAX: 489 8131. ,YDNEY:74 PARRAMATTA RD, STANMORE. PH : (02) 519 313 4 . FAX: (02) 519 3868 MELBOURNE DEALER: BLUESTAR COMPUTERS : 271 MAROONDAH HWY, RINGWOOD, 3134. PHONE: (03) 870 1800 FAX: (03) 879 3927 $2,685 TAX EX. $3,195 TAX INO. $3,595 TAX INC ASSEMBLED & TESTED IN AUSTRALIA. IDEAL CAD MACHINE! Postage rates $200 • $500 ... FREE $500 PLUS ... FREE ··-~ 11 ---~ $3,295 TAXEX $1 • $9.99 ......$3.00 $10 • $24.99 .. $3 .50 $25 • $49.99 .. $4.50 $50 • $99.99 .• $6.00 $100 • $199 ••• $7.00 -~ p~~JlJJu 80486-33 CPU ON BOARD CACHE. 4 MEG OF RAM 157Mhz LAN DMARK SPEED TEST .200 MEG HARO DISK 12ms ACCESS TIME 1.2M JAPANESE BRAND F.0.0 3.5'" 1.44M JAPANESE BRAND F.O.i> 101 EXTENDED '"CLICK'" KEYBOARD SERIAL, PARALLEL, GAMES PORTS 1 MEG VGA CARD. IBM• COMPATIBLE VGA COLOUR MONITOR (1024 x 768 Resolution) TOWER CASE & 220W POWER SUPPLY 3 YEAR '"A-l.lSTRALIAN'" PARTS & LABOUR WARRANTY SPEADSHEET, WORDPRCESSOR & DATABASE SOFTWARE. WITH 200 MEG DRIVE TAX INC. $2,050 TAXEX. .·• ·• · •tia~~151 .) 80486-25 CPU ON BOARD CACHE. 1 MEG OF RAM 11 5Mhz LANDMARK SPEED TEST 85 MEG HARD DISK 12ma ACCESS TIME 1.2M JAPANESE BRANO F.0.0 3.5'" 1.44M JAPANESE BRAND F.0.D 101 EXTENDED '"CLICK'" KEYBOARD SERI AL, PARALLEL, GAMES PORTS 1 MEG VGA CARD. IBM• COMPATIBLE VGA COLOU R MONITOR (1024 x 768 Resolution) MINI CASE & 200W POWER SUPPLY 3 YEAR '"AUSTRA.LI AN'" PARTS & LABOUR WARRANTY SPREADSHEET. WORDPROCESSOR & DATABASE SOFTWARE. $2 895 WITH 200 MEG DR IVE ~XECUT~ ~•• • ·•4 ·~.E?B•J • ~·•§ • • • •~ $3,295 TAX IMC. $2,,295 ::t RITRON RITRON EXECUTIVE RITRON $2 595 RITRON 80386-33 CPU 128K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 16 MEG 57 Mhz LANDMARK SPEED TEST 85 MEG HARD DISK 18ma ACC ESS TIME 1.2M JAPANESE BRAN D F.D.D 101 EXTENDED '"CLICK'" KEYBOARD SERI AL PARALLEL GAMES PORTS SU PA VG A COLOUR MONITOR (1024 x 768 Resolution) MINI CASE & 200W POWER SUPPLY 51 2K VGA CARD (256 COLOURS) IBM• COMPATI BLE 3 YEAR '"AUSTRALIAN'" PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. 80386SX-20 CPU 1 MEG RAM EXP TO 4 MEG 27Mhz LANDMARK SPEED TEST 1.2M JAPANESE F.F.D. 512K VGA CARD 85M HARD DISK DRIVE, 18ms ACCESS 101 EXTENDED ""CLICK'" KEYBOARD MINI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 Resolution) SERIAL PARALLEL GAMES PORTS 3 YEAR '" AUSTRALIAN'" PARTS & LABOUR WARRANTY IBM• COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE ASSEMBLED & TESTED IN AUSTRALIA. DOS 4.01 AN EXTRA................ 60 DOS 5.01 AN EXTRA................ $100 TAX INC. $1 ,265 TAX EX. RITRON EXECUTIVE RITRON SOFTWAREINCLUDED. • SHAREWARE SOFTWARE PLEASE NOTE SYSTEMS DO NOT COME WITH DOS. $3 795 ' TAX INC. $3,295 TAX EX. All sa les tax exempt orders to : RITRONICS W HOLESA L E The• po ■ tage ra te ■ are baelc po ■ tage only up to 5Kg. Road freigh t. bulky & fragile ltemo wi ll be ~;;~dt ~!te■ 56 Renver ~d 1 Clayto n, Victoria . Ph : (03) 543 2 !66 Fax: (03) 543 2648 MAIL ORQEf' & CORRESPONDENCE P.0 BOX 620, (CLAYTON, VICTORIA. 31 68. Errora & omml■ aon ■ excepted. Prteee & ■ peclflea ti o n ■ aibJect to change. •tBM, PC, XT, AT, ant rag later&J b'adem&nl ■ of lntamadonal Bu■ lneH Maeh lnea. , I 1·9 boxes 1·9 boxes 10+ 1-9 5 1/4" 5 1 /4" 31 /2" 31 /2" OS/00 OS/HO OS/OD OS/HO $4 .75 $9 .30 $8 .75 $17.50 10+ $4 .65 $9 .00 $8.40 $16.95 50+ $4.55 $8 .60 $8.00 $16.75 100+ 500+ $4.30 $8.40 $7.90 $16.50 $4 .20 $8.30 $7.80 $15.90 3 3 5 5 1/2"0D $19.95 1/2"HD $45.95 1/4"0D $14.95 1/4"HD $23.95 $18.95 $42.95 $12.95 $22.95 3 3 5 5 1/2"0D $28.50 1/2"HD $53.50 1/4"0D $22.95 1/4"HD $27.95 1 O+ 10+ 3 1/2"0D $23.95 31/2"HD $39.95 5 1/4"0D $12.95 5 1 /4"HD $19.95 $27.95 $52.50 $21.95 $26.95 $22.95 $37.95 $11.95 $18.95 . HARD DRIVES 42 MEG HARD DISK FOR XT 28ms ACCESS WIJ,H IDE/FDD CONTROLLER FAST STEPPER .......... $549 42MEG HARD DISK FOR AT 28 ms ACCESS WITH IDE/FDD CONTROLLER FAST STEPPER. ......... $359 •=r1filfflUJ;J•l•J<at>ttK•J;f;) • 18 ms ACCESS WITH IDE/FDD CONTROLLER VOICE COIL.. ............... $479 - ff11'd11itJ;J t)B]®tti•l;t)- 16ms ACCESS WITH IDE/FDD WARRANTY rnAR CONTROLLER VOICE COIL. ................ $695 Ch•~ I;tJ'I•] ttt Ji•] 19; tJ ;J •I•] Wt9 12ms «1•ACCESS 1•1~111iM;l• 1•1®tti•1;Pe WITH IDE/FDD 17ms ACCESS WITH IDE/FDD YEAR CONTROLLER VOICE COIL. ... ~~~.R.~~~.v•• $369 v A CONTROLLER VOICE COIL...~~~.~:~~.~.$1, 195 All Hard Disk capacities are formatted. IDE/FDD drives are already low level fo rmatted so you only have to "F DISK" to high level format them. Please note you need DOS 4.01 to format these to I their maximum capacity as dr ive "C" or otherwise you will have to partition as "C", "o··;•E:", etc. if you have an earlier versio n. DOS 5.0 UPGRADE NOW AVAILABLE ONLY $129 BITBLITZER 1234EMODEM RITRON 486-33 MAIN BOARD The BIT Blitzer 1234E is an automatic, intelligent, 300/300, 1200/1200, 1200/75 and 2400/2400 bps fu ll duplex, asynchronous and synchro nous External modem, which meets the CCITT V.21/V.22/V.22bis/V.23 and Bell 103/212A standards. The BIT Blitzer 1234E provides all the 1200 and 2400 bps, Hayes AT+ features in a compact, low power, cost effective, reliable package, whilst giving you V.23 capability as well. FEATURES: • Full duplex • Call progress monitoring • Auto dail • Loopback for remote dianoslics • Auto Answer • Internal speaker with Command • Auto Disconnect Protocal controlled volume settings • Tone & pulse dialing • 28 "S" Registers • Intel 80486 Microprocessor • IBM, XT and AT • Direct support for the Weitek 4167 coprocessor • Built-in cache controller: Optional 32-KB, 64-KB, 128.KB or 256KB cache memory • 128Kcache fitted. • Supports interleaved cache RAM for high speed CPU as well as 80486 burst mode.• Flexible DRAM 1-32MB • Sophisticated DRAM controller • AMI BIOS with built-in SETUP program • Support shado w RAM • Synchronous AT bus clock with programmable clock • Support fast A20 Gate & fast CPU reset to boost performance of software utilizing 80486 protected mode, such as OS/2, UNIX.. etc. • Eight expansion slots - Six 16 bi~ Two 8-bit Only ....... $420 X18131 ...... .. .................................................. $1,995 3 1/2" DRIVE KIT. Y.E DATA 3.5" 1.44/720/360 DRIVJE • 5 114" Mounting bracket • Power supply adapter • Cable adapter ~ _ • Floppy disk controller card which controls 1.441720/360 drives -~ I- ' , Complete instructions to Install a 3.5" in your existing computer. Enjoy the higher density & easy handling of 3.5" floppy diskettes! C11915 ........ ... ........ $295 MATH CO-PROCESSOR SPECIALS 80287XL. .. replaces 80287-6 80287-8 80287-10 .............. $295 80387DX·33............................ .............................. $595 80387SX-16............................ . ............................ $450 80387SX-20............................ . ........................... $495 I!•I•] ;g W\'t'ltfil ;I •1-1 "MegaRAM" Memory board ~ . 4 PORT SERIAL CARD This new generaUon memory enhanced , ' ' ·, board offers O wait state high speed ' 01 operation. It can take up to 6MBytes ~ 4 ~ 256K or 1 x 1M DRAM chip. ~p to 7 cards can be. used together (42MB EMS). nd 11 It 1s 100% EMS 3,2 & 4.0 comp atible, a beSI of all can be used In an XT, AT or 386 because It la 8 bi~ 16 bit conflgerable. So get yourself a Mega for the price of• Mini. X18051 .................................................... ......... .......... ................... ....... $299. 00 (Software Output cables included.) The PE-514A has 4 aerial ports for asynchronous communication. These ports can be used to connect your PC with a aerial printer, MODEM, serial mouse or other aerial devlceo which use an RS232C Interface The interface is a DTE type with 8 male 0825 P for 4 aerial port outpul It supports DOS. & XENIX. X18155 ......... $199 ROD IRVING ELECTRONICS CITY: 48 A'BECKETT ST, ME:LBOURNE NORTHCOTE: 425 HIGH ST, NORTHCOTE SYDNEY: 74 PARRAMAITA RD, STANMORE MAIL ORDER: 56 RENVER RD, CLAYTON PH: PH: PH: PH: (03) (03) (02) (03) 663 489 519 543 615 1 8866 3134 7877 FAX: FAX: FAX: FAX: (03) 639 1641 AS PHONE. (02) 519 3868 (03) 543 2648 All sa les tax exempt orders and wholesale inquiries to : cl lTRONICS WHOLESALE 56 Renver Road Clay1on Phone J03) 543 2166 13 hnes 1 Fa, 10315432648 Errors and omissions excepted Prices and spec1f1cat1ons sub1ect to change I~ lr_. . . .,. ;:t,~~,:.,~ !< =1~; '"9'~"""" :~!~·,,~:, l ,119si••e<I S.,~ ~ -~ ~ ·o.,,o, .. , Pr a<lm;lrl,.~ a' lheo•• P ~ l••POwO,,I\ SERVICEMAN'S LOG A very circuitous exercise Rare or unknown TV sets can present a difficult situation for .any serviceman. And in this case, the situation was further aggravated because the circuit diagram was inadequate and because the set employed unusual circuitry. The set in question was of French design, a Thomson model TS5152. Thomson sets appeared on the Australian market several years ago and I have encountered two or three of them in the past. The last one was a model TS5108 which had a tricky vertical scan fault. It was described in these notes in May 1989. At the time, I established that they were imported by Lemair Aust. Pty Ltd (23 Amax Avenue, Girraween, 2145) and that service and spare parts were being handled by Hills Telefix Service (10 Wigs Rd, Riverwood, 2210. Phone (02) 533 4855). As far as I can determine, this situation still applies. This information may assist anyone else who encounters these sets. Relatively speaking, I suppose that the faults in this latest set were not all that unusual. However, I could have been caught had I acted too hastily and the story is worth telling for that reason alone. But the other aspect is the one I hinted at earlier; the combination of an unusual circuit and lack of adequate data to go with it. And this circuit is unusual. So much so that I found much of it hard to follow. This is not a criticism of the set's design or its designers . If they can find a better way to do things , then good luck to them. The set is an excellent performer and, by all accounts, has a better than average reliability record. The fact that I have encountered so few of them would seem to support this. But a strange circuit, no matter how justified, can still present a problem at the service level. That's why a good circuit and other data are vital in such cases. But this is where the system fell down , because the circuit contained a number of errors -some trivial and some quite frustrating. Dead fuse 11-l~ se:.-r ~MF'L-01..(ED UN\JSUALCI 'RC.U1--f"1<'-f rv OF F1<E:NC.H DE:Sl G N,, , 40 SILICON CHIP As the set came in, the fault was quite straightforward; it was simply dead. One obvious reason for this was that the mains fuses were blown. These carry the part number FP0l and type number TlA, signifying a delay type 1A fuse. And this was the first circuit discrepancy; there are two such fuses in the set but only one shown on the circuit. This discrepancy is quite trivial of course and I thought no more about it. But it was a sign of things to come. Wµat was more important right then was to find the cause of the fuse failure . I naturally suspected that it was something in the power supply, most probably the regulator transistor. In fact, after studying the circuit, I wasn't too sure as to how it all functioned. Mains transformer UP0l has two secondaries, each feeding a bridge rectifier, DP0l and DP02 . The lower CP21 I1]'4,]S'- .ti.. BPO, _'"'-+l-'-E➔C lO_•fVY'~,--0-·_·+--+,◄...~,..~ '; ~ ...-.--fOJ '{[_:---+-...._---+---+',___._--..Uf'IO•,----;,-,------.---, >-~+=>=--.._-+-~-ro_,_•o+, L .J • I L FPOI TU OP l ~ ,......oo· I ) JNO A~•s •_, :)-., ~ UE • Ot~f"I S " :J" 1,._.-: S•{ "! !H ::>IY.· i A::)C: Fig.1: the power supply circuit in the Thomson model TS5152. Note the BC337 transistor (TP01) immediately to the right of the power supply board. Where was it? And where was the board on which it is shown? winding and DP0l, in conjunction with capacitor CP09 (lO00µF), produces a 23V rail, which goes up and to the left. It also connects to transistor TP01, a BC337 immediately to the right, and which appears to be a voltage regulator providing an auxiliary rail. The upper secondary winding and bridge DP02 produces what appears to be the main rail, at 108V. This connects to the horizontal output transformer primary and thence to the horizontal output transistor, TL02. down the drain - I eventually found where it should have been, but there was only unused copper pattern. I eventually worked out that TFlO and TFl 1 form part of the vertical circuit and, later again, found a "fine print" notation on the bottom of the circuit, under the heading "AUST ONLY", saying, in effect, to delete subboard PB 95 0800 and to add a diode, apparently in place of the BC33 7 and associated circuitry. At that point it became obvious that I had wandered up the garden path and I gave up trying to rationalise all The phantom sub-board this. But I did wake up to one interestHaving digested that much, I de- ing and useful point about the part cided that the BC337 voltage regula- numbering system. It appears that the tor transistor (TP0l) was a likely sus- first letter relates to the component pect. The only snag was, I couldn't . ("C" for a capacitor, "T" for a transisfind it. According to the circuit, it tor, etc), while the second letter rewas mounted on a sub-board, PB 95 lates to its circuit function. 0800, along with transistors TFlO and Thus, "P" indicates the power supTF11. ply; "L" indicates the line (horizonIn fact, there is no such sub-board. tal) system; "F'; indicates the frame (vertical) system, and so on. It can be After much searching, I found TFlO and TFl 1 mounted on the main board a help and is worth remembering. and, what was more, I realised that The next suspect was transistor they have no electrical association TP0l. TP0l? Hadn't I just given that with the BC337, as a closer examina- away? Yes, indeed, but there was a tion of the circuit will confirm. second TP0l, this time a BU807, imSo where was the BC337, TP0l? mediately to the right of the aforeAnswer: it didn't exist either. By trac- mentioned sub-board. So that was ing the copper pattern - more time another one up against the circuit draughtsman's duck house. It appears to perform some kind of regulator function but just how I was unable to work out. However, since it is a heavy duty device and is connected directly between the 108V rail and chassis, it was a natural suspect. Sure enough, it had broken down . If only I had checked it first. Anyway, that was it; a new one was fitted, the two fuses replaced and the set fired up. It gave a first class picture. End of story? Well, it should have been and I thought it was. But the COMING NEXT MONTH* • UHF TV Transmitter Transmits from your VCR to a second TV set in another part of the house without messy connecting wires. • Baby Monitor This useful project enables you to monitor the baby's room via an FM radio link so that you can attend to other chores. • lnfrared Door Minder It sounds a buzzer when someone walks through an invisible beam. * Subject to space availability. NOVEMBER 1991 41 lt" ,RANSPIREX> 111A, ~ se:.,"BE-l-01\lGS "'f'O H\S AG6.t:> GRANt>M01'""HE:'Ro ... ~ owner wasn't in a hurry so I let this one run on the bench for the next few days, putting it through a few switchoff, switch-on cycles in the process. All went well until I was about to ring the owner and tell him he could pick it up. Then I switched it on one morning and bingo! - it was as dead as the proverbial dodo. Not surprisingly, both fuses had gone again. I immediately suspected the replacement transistor, since it was a substitute type, although its ratings should have been more than adequate. But no, it checked out OK. De-gauss circuit I decided to live dangerously, fitted two more fuses and switched on. The set worked, which was a bit of a blow because it now meant that I had an intermittent to contend with. On the other hand, it immediately threw suspicion on another ofmy favourite fuse blowers: the de-gauss circuit and particularly the thermistor. I've dealt with faults of this kind many times before in these notes. In this case, the "thermistor" is actually a 3-terminal commercial package which is used in a number of sets. As nearly as I can determine, it is similar to a system I dealt with in some detail back in July 1990, in regard to an AWA Thorn 3500. This 42 SILICON CHIP used a positive temperature coefficient thermistor (PTC) and a voltage dependent resistor, to ensure minimum current through the de-gauss coils after the de-gauss function. However, this was the first time I had seen this package portrayed in any detail, as it is in this circuit. And while I accepted the drawing initially, I did a double take when I looked at it in greater detail. There's just no way that I can accept the idea of a PTC thermistor (which has low resistance when cold) being connected directly across the mains, as portrayed here. Not onlywould the de-gauss function not work but it would simply be another "little beaut fuse blower". So, unless I am much mistaken, this is another circuit blue. Anyway, this is a standard package which I carry in stock, so there was no trouble in replacing it. And that, I was confident, would settle it. Except that, a couple of days later, it failed again and, as before, at switch-on. This last point maintained my belief that it was still a de-gauss circuit problem. Not that there is much left in a typical de-gauss circuit. But there was in this case - a 68nF, 400V capacitor (CP0l) across the de-gauss coils. I pulled it out and checked it. It checked OK but I was not convinced. I was remembering some earlier experi- ences, involving some 0.lµF capacitors fitted across the mains in the old General GC181 sets. These were found to have a selfhealing function; not by design (there are such devices) but purely by accident. They would break down, blow a fuse and clear the breakdown all in one operation. So the serviceman was faced with a blown fuse and no explanation for it. A new fuse might last anything from a few hours to several months - and the consequences can be imagined. This was a much smaller capacitor, both electrically and physically, but could it have a similar fault? One way to answer the question would be to disconnect the de-gauss circuit and run the set for several days and see what happened. However, I had a similar capacitor on hand and it was a simple job to fit it. Granted, it was only similar. The one that came out was a quite tiny unit, probably a mylar type, whereas the best I could find was a disc ceramic, physically much larger and with rating of 3kV. There was plenty of room for the larger unit and I reasoned that the higher voltage rating wouldn't go amiss. All right, so 3kV is a bit of an overkill, but it was the closest I had and I wasn't going to waste a lot of effort just to satisfy a technical nicety. Anyway, for once, I hit the jackpot. The set ran for several days, through many on-off cycles, and was finally returned to the customer. That was several months ago and there has been no further trouble. Sorry, Mr Thomson; a nice set but no prizes for the circuit diagram. Tremendous trifles To change the subject, here are a few thoughts on what some may consider to be in the "tremendous trifles" category. And maybe they are but we should always remember that, for the customer, the reason a piece of equipment has failed is often of less importance than the simple fact that it has failed. Regardless of the cause, no matter how trivial, the end result is the same; the customer is temporarily deprived of the equipment - TV set, radio set, microwave oven, or whatever. On top of that, he has to arrange to have it serviced and transported, all of which can easily add up to a degree of frus- that he couldn't get anything out of it. TETIA TV TIP Sharp 9C140 (Kriesler 37-104 and similar Philips). Symptom : No sound or picture. Ticking sound from the chassis, like a slow hiccup which persists for some minutes after the power is turned off. Cure: R644, a 2.2Q 0.25W fusible resistor had gone open circuit. This resistor feeds the main B+ to the line output stage and also to the horizontal oscillator. The ticking arose from the chopper power supply, due to the total lack of a load on the supply. TETIA TV Tip is supplied by the Tasmanian branch of the Electronic Technician 's Institute ofAustralia. Contact Jim Lawler, 16 Adina St, Geilston Bay, 7015. tration and, possibly, some ill-will. Of course, sometimes it's the customer's fault and believe m e, the mistakes they can make are often way out. But that's their problem. What we have to do is to make sure that no act of carelessness on our part - trivial though it may seem - precipitates such a situation. Take my word for it; the customer doesn't regard our mistakes as trivial. So what brought this on? What disgraceful technical gaffe am I about to reveal? None really, but one u nusual fault did highlight a procedural weakness which could - and did - produce, in mild form, the kin d of situation I've described. It all started w h en a customer brought in a Sharp video recorder, a model VC-381. It had no specific fault but the owner felt that it was due for a general overhaul. And h e was right. It was a quite grotty, with a fair build-up of oxide on the heads and guides. These were duly cleaned, the rest of the mechanism lubricated and a faulty idler pulley replaced. It was then checked out on the bench and passed as OK all round. And that was more or less it. The owner duly collected the machine and I didn't expect to hear any more about it. Nor did I fo r a couple of days. Then he was on the phone complaining It appeared to be working mechani- cally, all the indicator lights were up and so on, but it wouldn't produce any picture. Such situations have occurred before and I have a few tricks which can help pinpoint anything the customer ~ ay have done to create it. The first thing to establish is whether the correct channel has been selected on the TV set to match the RF output channel of the recorder. This sounds simple enough but people do get confused. Also , it is quite possible for the output channel selector switch to be moved while the recorder is being handled. Another trap is the presence of a VHF /UHF selector switch on some TV sets and, if this is in the UHF position while the user is trying to bring in signals on, say, VHF channel 3, the result will be nothing. So my routine is to instruct the customer to try playing a pre-recorded tape , then try both channels and double check any other switches. This is a very simple and effective way of guiding the customer to get the TV set onto the correct channel. I went through this with the customer, suggested h e check it all out, and then ring me back and report. He was back on the phone again 10 minutes later. "Yeah, I got a picture but it's so blankety-blank snowy it's not worth watching". I double checked what he had done. It was just possible that he had managed to select a harmonic or something equally silly, but he was adamant that he had done everything correctly. So there was no option but to check out the machine again and, if it was OK, to suspect the TV set. A couple of days later, the machine was back on my bench and this time, attached to it, was the interconnecting lead to the TV set (about half the customers who bring in recorders leave this lead connected). Such accessories can be quite a nuisance. Once they become separated from the main device they are easily mislaid and, if they are not labelled, forgotten. The customer then takes his machine home, having also forgotten about it, and can't get everything together. The result is much confusion and ill-will. Anyway, I was about to disconnect this lead and fit one of my own when I realised that it was long enough to AUSTRALIAN MADE TEST EQUIPMENT YOU CAN TRUST SHORTED TURNS TEST R Built-in meter to check EHT transformers including split diode type, yokes and dri ve transformers. $78.00 + $3.00 p&p DEGAUSSING WAND Strong mag netic field , larger than usual coi l with multicore centre. Double insulated for yo ur safety. Also fitted with momentary on/off switch. 240V AC 2.2 amps. Just about as important as having a soldering iron in your toolbox! $75.00 + $10.00 p&p HI-VOLTAGE PROBE j Built-in meter reads positive or negative 0-50kV . For checking EHT and focus as well as any other hi-tension voltages. ;m $98.00 + $5.00 p&p SPECIAL PRICE REMOTE CONTROL TESTER (TO END OF NOV. 1991) Designed to test infrared or ultrasonic control un its. Wi th the extension lead you can also test infrared units which cannot be placed in front of the testing unit. Requ ires a 9V battery. Output is via a LED and piezo speaker. $70.00 + $4.00 p&p LASER DETECTOR PROBE A new addition to the remote control tester. Comparable with units costin g $500 or more . You can test the laser pick- up in compact disc players. $27 .00 + $2.00 p&p NEW PRODUCT TEST TUNER Save time and money with this teste r. Helps you determ ine if you have a tu ner problem, an AGC problem or a fau lt in the IF stages. $250.00 (Tax inc.) TUNER REPAIRS From $17 exchange+ p&p Cheque, Money Order, Bankcard or Mastercard 216 Canterbu ry Road, Revesby, NSW 2212. '"B"" (02) 774 1154 ,(" PAX 7\ (02) 77 4 1154 NOV EMBER 1991 43 SERVICEMAN'S LOG - CTD reach my test monitor. So, without further ado, I plugged it straight in, switched on and pushed in a test tape. And up came a picture immediately. But the customer was right; it was as sick as the proverbial dog, barely locking into colour. On an impulse I pulled out the lead and put a meter on it. And that was it; open circuit on the inner conductor. Just where the problem was I didn't bother to find out but it was an unusual fault, particularly as this lead normally suffers very little movement. It did make m~ realise, however, that I should check any such accessories in the future if they are supplied. No nothing And while on the subject of leads, here's another one. A customer brought in a General colour TV set, model GC187; a set which has been on the market for about eight years now. It was one of those abrupt confrontations. He simply pushed it across the counter with the brusque comment, "It's dead. Won't go. No picture, no sound, no nothing". Ignoring the double negative, I got the picture (no pun intended!) When I switched the set on it was as the customer had said; totally dead. I pulled the back off and made for a convenient HT rail check point. Still dead. Back tracking, I was soon into the mains input area, involving the mains switch on the front panel the mains fuse, and connections to the board, in that order. The fuse was OK, as was the switch, which left only one possible culprit; the mains cord itself. The multimeter confirmed this; one leg was open. This point settled, I looked along it for possible signs of damage. I found none. This was somewhat surprising. Open circuit cords are not all that rare but there is usually some obvious physical damage. Apart from typical domestic accidents and lack of care, I have seen cords that were chewed by ANTRIM dogs and which , in addition to the teeth marks , showed unmistakable signs of arcing. What happened to Pongo in each of these cases is not known. This cord was fitted with a 3-pin plug moulded to it, so there was no point in trying to repair it. Fortunately, I had salvaged several perfectly good cords from discarded sets against just such a need and one of these filled the bill nicely. When the customer came to collect the set, I explained what had happened. Suddenly, he was a lot more communicative. Shrugging his shoulders , he commented resignedly, "Oh, this is always happening". Curious , I pressed him for more details. And it transpired that the set belongs to his aged mother, who lives alone and has a fetish about removing plugs from power points, when the appliances are off. But the snag is that she always jerks them out by the cord; no one can persuade her to pull the plug itself. The result is a continuing saga of open circuit power cords. So that's another one to add to the list of power cord abuse. SC ATTENTION AUDIO SERVICE TECHNICIANS! TOROIDAL TRANSFORMERS The Audio Interface is Now Available! • • • • Now made in Australia Standard range 15VA to 2kVA Large ex-stock quantities available Competitive pricing available for OEMs & resellers • Simply the best transformers all round HARBUCH ELECTRONICS PTV LTD 90 George St, Hornsby, NSW 2077. Phone (02) 476 5854 Fax (02) 476 3231 44 SrLICON CHTP For years, you have had to endure an untidy mass of cables and connections to test audio equipment. The Audio Interface solves all that. This precision made instrument enables you to link all the audio test gear on your service bench to one control panel. No more temporary hookups - just one lead in, one lead out. You can do gain and power measurements up to 800 watts on stereo gear. Flick a switch or a knob and it's there. All this and more for an investment of $1495. Phone now for a free brochure. Kingsley Electronics, 17 Blackburn Drive, Cheltenham, Vic. (03) 583 4020. 'AR ELECTRONICS JAYCAR ' AR FLFCTRONICS JA'rCAR ' A,1 FLECTRONICS -AYCAR A,l ELECTRONICS aA'rCAR AR EcECTRONICS AYCAR ARE C'TRONICS .. A,CAR ~- ,Rf t" -R r NlrS. A'rCAR Lr A~ . E. A~ F f r •· ;,, . , ,c A E"Ec 'AR t " Ee : l '" JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ~~- i , · Al = A Cv AR '" -E JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELEC TRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYC AR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELEC TRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELEC TRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .IAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTR01'1CS ELECTROII.ICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR AH E ARE r 'R ._ Al EL: A,~ E ;r~ E _1- c_ re in I alarm chronoaranh !I's afluorescenl IIOhl wllh a4 wall lube. It's abug zapper wllh a 4 wall fluorescent tube and an Inverter to zap bugs that are allracted to II wllhln a1/2 acre range. It's atorch wilh along range beam and a red flashing spotllghlforemergencies.Also supplied wilh a3.5 metre lead ~!'-liWCS:il foroperalingfromyourcars w, •. '.AR El * 511 DUAL IMPEDANCE SPEAKER ,,.._,_..,,..... i-Jr.t=,.•,..,.-.,.,~.,. 4 ohms and 8 ohms Cat. AS-3010 , AR E: :!~E $14.95 ~ . 9 - $5 ·1 ALARM PANEL TELEPHONE DIALLER SAVE $:S. 95 • :;~ I 240V • . Don't miss lhls one. SPST 240V AC 30A relay. II WIi i switch a massive 7500walls. Spade lug ,">rL:tf] ;;6~;:·AL PRICE $9.95 0 E1□[;3C3<at>oomm0° * ~<at>um<at>E1 ~m~<at>oom 0~u<at>l<at>u<at>m 0CB [1[1<at>001? SAVE $20 I I, •• II , .a_ - 1£9 fe!iiI~i!i\'c!m !l'!~f!1'8. easy lo Install. Mounts on slandard round Juncllon box. .._ ~ Automatically turns on two floodlights when someone comes within detector range. Deleclion range 40 feel long by 60 feet wide. Lights slay on for a minimum of 10 seoonds and up to 15 minules (adjuslable). Works only al nigh!. Globes NOT supplied - slandard Portafloods available everywhere. Cat. LA-5132 · . WAS $99.50 30~ .9uu . $&5 SAVE $54.50 * ----1 NM ._, 9 , ; OUTDOOR INPRA RED . CRO ADAPTOR KIT Rei: EA March/June 1991 This projecl is afully fealured osclllosoope lhal uses a low-cost convenlional compuler monllor as the display. 1rs not your average CRO adaptor either! II can display waveforms of over 1MHz, can measure DC volls, (not display, aclually measure), measure frequency and peak to peak vollage and It's astorage CRO! The Jaycar kit Includes 3 PC boards, mains transformer, IC sockets, switches, sockels, knobs and all specified componenls. No box supplied. Cal.KA-1735 WAS $179.50 ~ .9ua $159.50 SAVE $20 4-CHANNEL LIGHTING DESK KIT .L r Reier Silicon Chip June 1991 This 4-channel lighling desk is inlended tor lhealre, dlsoo and m~sic group applicalions. II has heavy duly circuitry and is able to cope with spollights raled up lo 1000 walls or more. Operating features • Four channels • 60mm slider pols • Click aclion flash switc~ ,~ wilh inlegral LEDs • Separate dimming for each channel • Master dimmer oontro' • Flash on each channel • Masler dimmer for flash • 4-channel chaser • Adjuslable ch;,~r rate • Single slep for chaser • Chaser on and off • Flash switch LEDs mimic lamp display The Jaycar kit includes pre punched and silk screen case, origina, Cand Kswitches, original slider pots (Jaycar supplied the samples lo Silioon Chip) and all specified oomponents. Bev ,re of kils With non original parts. $529 ~ C AR>- f C,' ROr.t C,; Ar, Ru [(,.:, Al'<, . cCTFi0,,1c AR F" cC' R0 ,.1cs :i~~;[ :;;=ii :AR Et :AR Et :AR Et : : . ;1: ~: , ;AR El :AR El ·- ;;: ~: .• $25 SAVE $14.95 Cat. LA-5272 Model GVM-50 Normally $24.95 \ •AR El AR El :AR El Model UA-2A Normally $39.95 ._?&:J..(,,t,.~, ---,y : • This unit consists of oold sensor detector (which Is situated in the bilge) wiring loom and control unit/alarm. II has an on-off test swllch alarm buzzer and lighl. Both light and buzzer go off when fume concentration Is still well below (20%) explosive level. The unit also includes a tesling gas spray pack, SEE CATALOGUE FOR FULL DETAILS Modei GVM-50 •· ::: ~: ::: ~: :AR El •, ;;: ~: Modei UA• 2A This unit is permanently wired lnloyourboatand does notcontalnatestswllch, lls operation is automatic. II consists of an allracllve circular transducer, cold sensor and lesling gas. SEE CATALOGUE FOR FULL DETAILS Cal. LA-5270 ~1 :;: ~~ RELAY •;;: ~: BARGAIN •:;: ~: L r ~-r . :AR El • ;AR El . (;: ~: J!il;:,/J!,};'~ Normally $8.95 NORMALLY $179 3di-/-",,t,.A, .9uu $159 :' :AR Et • : AR Et • ;AR E, • :AR E: : ~;: ~I • :AR El Normally $9.95 ~ .9"uu $&.95 SAVE $:S ~:;:~~:~rP. Cat Price $49.95 3#,:./.,(,,t,.~, .9uu ~-.,, 'AR El :::~: lnoorporales • handheld sRlpwatcn • i!llpslopwalch • alarm chronograph wrlsl walch •whistle• Fealures • quartz accuracy• 1/100 second chronograph with lap time• displays hours, minutes, seoonds, month, date and day flag • alarm and hourly chime function • ballery Included Cat. XC-0200 This dialler WIii connect to virtually any home/business alarm panel. II has bulll-ln microphone which records a 16 seoond message by you and lhen when the alarm Is triggered will send the message to up to four different numbers, or any combination of lhe same. Suilable for tone and pulse systems. Easy to connecl lo bolh alarm systems (N/C terminal) and telephone (2 wire). Requires 12V DC_ from alarm panel. Cat. LA-5190 '\F ELEC TRC ELECTRC ELECTRC ELECTRC ELECTRC ELECTRC ELECTRC :s NIGHT BLASTER Mulllpurpose ouldoor lighl, insect killer, lanlern, spolllghl, emergency llghl ::i!=::::~:a ~l~a~t1\~Hohter socket. Requires Cat.ST-3012 SR ELEC TRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS -ms======================================================:imi::::i=ii;;ii:i::::::::::::m■:CTRC f• ;AR El :AR , \ R oi: a F ELECTRONICS ELECTRONICS FLECTRONICS ELECTRONICS ELECTRONICS i:LECTRONICS E, ECTRONIC :AR Et :AR Et :AR El ·• ;;: ~: :AR El :AR El :AR El :AREi :AR El :AR El . ; AR El ;AR El · :AR El ';AR El :AR El :AR El ;AR El ;AR El ;AR El :AR El ;AR El ;AR El '.AR El ,AR El :AR El ;AR El ,AR El ;AR El : ;AR El :AR El ;AR El :AR El ;AR El ;AR El :AR El ;AR El ;AR El . ;AR El ;AR El ;AR El · ;AR El ;AR El . ;AR El ;AR El :AR El ' ;AR El ;AR El ;AR El . :AR El ;AR El :AR El ·•AR El :AR El ~8 JA ,CAR JAY CAR JAYC AR JAYCAR ELFCTRONICS ELECTRONICS fcL ECTRONICS ELECTRONICS JA YCAR JA YCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRON ICS JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR ELECTRONICS JAYCAR JAYCAR ELECTRONICS JAYCAR JAYCAR ELECTRONICS JAYCAR JA'i.CAR.£LECTRON!CS.IAYCAB ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS 1JAYCAR El ECI BO'IICS IAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRQNJr.s JAYCAR JAYCAR JAYCAR IAYCAB ELECTRC ELECTRC ELECTRC El ECIB( -Cl.R .,_ ,He AR Af1 Af Ar AF. Jaycar proudly announce lhe release of our new project box. The Jaybox is lhe ideal size box for many popular projecls. ll's perfeclly suiled for power supplies and lesl equipment A major advanlage over olher boxes is ils slol-in 1.2mm aluminium fronl and rear panels. Olher fealures include: • buill-in slandoffs for PCB's elc • venlilalion slols in bolh lop and bollom panel • lhe 4 screw fasleners are melal lhread - nol self lappers • 4 plaslic feel supplied • popular size 250(W) x 170(0) x 75(H)mm O.D. • black in colour Cal. HP-5930 v ,,' ,A Ji- ARC AR I ,AR~ Al A "' v v • ( ' "" e $19.95 GEL BATTERY MADNESS Slack up now al lhese crazy Birthday Prices cC-H'-- .: cCTRC ECTRC ECTRC ECTRC ~CTRC =cTRC ':CTRC cCTRC 2CTRC ~CTRC ECTRC cCTRC ECTRC : CTRO .:CTRO :CTRO ·cTRO =cTRO .:CTRO cCTRO :CTRO :cTRo =CTRO cCTRO .:CTRO =cTRo . ·· .• ·· • =cTRo :· 'CTRO . :CTRO .:C1HO :crno ::CTRO 2CTRO .:CTRO ·,CTRO ::CTRO cCTRO =cTRo ':CTRO ECTRO ECTRO ::CTRO ECTRO ECTRO ECTRO ECTRO ECTRO ECTRO ECTRO ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC ECTRC 1A BA BOOmA 1.2A 2.4A 2.7A 6.5A 24A 38A 10 globes NORMALLY $12.95 ~.9uu $9.95 SAVE $:S · • . .•: •· . .· • : ·. · HORN MIDRANGE BARGAINS 6V 6V 12V 12V 12V 12V 12V 12V 12V $8.95 $16.95 $16.95 $20.00 $29.95 $32.95 $43.50 $99.95 $149.95 See calalogue for full delails S 11 X '7 11 llOW Cal. SB-2478 Freq 2kHz -1 SkHz Cal. CM-2084 Cal. SB-2482 NORMALLY $32.95 ~~ .9uce $25.95 SAVE $7 Cal. SB-2480 Cal. SB-2483 Cal. SB-2484 Cal. SB-2486 ... X 10.5 11 llOW Cal. SB-2492 Freq 1.SkHz - 14kHz Cal. CM-2082 Cal. SB-2495 100 WATT 12V DC 240VAC INVERTER Incredibly small lnverler. Low ballery alarm, 10W ballery shuldown. 90% efficlenl. See calalogue for ful I delails. Cal. Ml-5030 NORMALLY $189.50 .9uu $159.50 SAVE $:SO so~ •ms Cal. SB-2479 •ms NORMALLY $47.95 ~.9'uu$40 SAVE $7.95 BUILD YOUR OWN Tl!ST l!QUIPMENT by HDavidson This book !ells you aboul ca;nlrucling inexpensive, high capacily lroubleshooling equlpmenl for almosl any purpa;e by designing PC baords, subsliluling componenls, building and lesling componenls and pulling your compleled inslrumenls lo work. Wilh lhese you can !hen lroubleshool: lelevisions, slereos, compulers, CD players, Ham radios, microwave ovens, camcorders, eleclric molars, power supplies and cables plus much more. 286 pages soflcover 232 x 186mm Cal. BT-1338 BEGINNERS GUIDE TO SCHEMATICS $:54.95 Dl!!SIGN AND BUILD ELECTRONIC POWER liUPPLll!!S by I Golllieb This book will bring you up lo dale on lodays mos! advanced power supply circuil, componenls and measuremenl procedures. Also includes eleclronic and synchronous reclificalion, resonanl-mode swilching, IGBT power supplies and MCT lhyrislors. 163 pages soflcovers 234 x 187mm Cal. BT-1336 j / I This book lakes you slep-by-slep lhrough every phase of underslanding and using eleclronic circuil diagrams or schemalics. Discover which sysmbols slyand for: capacilors, resislors, induclors, lransformers, swilches, conduclors, cables, balleries, elc. Find oul how !hey work logelher, combinalions and how lo draw !hem. 129 pages soflcover 130 x 210mm - 2nd Edilion Cal. BT-1334 $22.95 .,, $:54.95 a'i'• t;~:;;;;;;:;;:::;::;;:::::;;;:;;:;::;;:;;;:::;::;;::::;;;:;;;;::;;:;:;::::;:;::=== ELECTRONICS_JAYCAR :cLECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR FLECTRONICS JAYCAR ELECTRONICS JAYCAR FLECTRONICS JAYCAR fl~CTRON1C.;; ECTRC CS JAY R CS JAYC AR CS JAYC AR CS JAYC AR CS JAYCAR ELECTRONICS ELECTRONICS ELE CTRONICS ELE CTRONICS J AYC AR JAYC AR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ~~ JAY~A~ ELE~TR?NI~ ~~~~~~ : L:~~R? NI~~ J AY ~ E ~TRO~! ~~ JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR AH Al \ C Al A c AR A'rCAR IAYC Af< [ E E ELECTRONIC~ ~~~~~~ ~~~~~~ ~~~~?NI~~~~~~~!~?~!~~~~;~~~~~~~~~~~!~~~~~~~ F ELECTRONICS ELECTRONICS ELECTRONICS El ECTRON,CS JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELEC TRONICS ELECTRONICS ELECTRONICS JAYCAR JA'fCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JA'rCAR JAYCAR ELfCTRO"JICS ELECTRONICS ELECTRO,-.ICS ELECTRONICS JA'rCAR JA'rCAR JAYCAR JAYCAF, fLFCmo·,1, ELFCThCNlt c FLFC fRONIC<i tLEClRONICS E E :AR : AR : AR ·· :AR :AR EU EL! Eli ELI El.I ::AR ELI :AR ELI :AR !:LI :AR EL! : AR EL! ::AR FL f : An Eel :AR Ect :AR EL :AR EL · :AR E_, ell, VHS VIDEO TAPE CASE Ideal for making short !apes or repairing damaged ones. (No lape, Juslcase.) Cat AR-1435 Was $3.95 , SPIROMATIC INDOOR ANTENNA r.ff=f'-f_:~-=- ;;·~ ~ ~~ g;,,.tleia,/NU $2 Reverse 5 pin DIN lead Made for video. Pins are reversed, tenglh 1.5 melres. Cal AV-6525 Arista price $5.95 8,.,.tleia,/l'-/61, .50~ Ciil,t~m=a -=~,D 1H ::'....ECT 1R FLfCT ,A R ,R ,R ,R ,R E=LECT ELECT ELECT ELFCT FLEC T E:U:CT R ,R .R R .R .R ELEC T ELECTI EU:CT' ELECTI ELECT EL~CT R R R R R R ELECT ELECTI ELECTI ELECT ELECT ELECT :=~~~g R R R R R R 'P . ,., .1. b: • e, For prime receplion areas, sils on lop V /1"1,MiPfr f'"/(} " f your TV Pop lar sp' ral design ,,_.,,_,, I!, ~OOohm ~ ble s~ppli e~. ' sAr•g $5.00 Burglar alarm tape b IOC ks To suit window tape LA-5050. Self adheasive. Cal LA-5060 Catalogue price $ 1 ,25 11 'Jl ,/ / Professional cable tt CU er $9.95 1111••···•--.. . . -==~~z:'.'.::1Z::: Pack qty Price 20 100 20 100 20 100 $6.95 $23.95 $2.50 $8.95 $4.50 $14.95 (Size 25 x 20mm) Cat HP-1150 HP-11 51 HP-1155 HP-1156 HP-1"60 HP-1161 <at> BUSHES <at> Now available, se parate bags of bushes to suit the new silicon Impregnated rubber washers and mica washers T0220 T03 Pkl 100 Pkl 100 ,8.95 9.95 Cat HP-1166 Cal HP-1 168 D Size NiCad AA Size NiCad 1.2Ah current 450mAh Cal SB-2460 Cal SB-2452 Normally $6.95 Normally $3,50ea NOW$5 NOW 4 for $10 .· . ,• . . Anolher surplus slock buy which will save you heaps. This lime il's a cable culler. They are designed lo cul copper and alumi niumcableuplo38sqmm. They willslicelhroughcable with the greatesl of ease and strip as well. Length 215mm (8"'). Eve ry loolbox needs one. Trade price $21.89 plus tax. Cat TH-1823 Jaycar price , ' v/,-.tMa.11, / 1"/~t," .5 0 ~ "(I S~-. ;11!,f II Type T03 T03 T0220 T0220 T03-P T03-P ................ 240V NE2 NEON A 90V neon pre-wired with res istor for 240V. Wire tenglh 00mm. Resislor is covered with heatshrink lubing. Cat SL-2691 Normally .75jt ... ; ~ 'P ,/ .I. • Vt/4/f40.fl/f"/C,t, -11..._ "(I 1 O for $2 . :AR EL. CAR EL: CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL SAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CAR EL CARE', CAR EL CAR El CAR El CAR EL CAR El CAR E. CAR El ·cAR El CAR El :g:=~: ' CAR El 'CAR El 'CAR El 'CAR El 'CAR El 'CAR El 'CAR El 'CAR E 'CARE 'CAR El 'CAR El ·'CAR E ELfCTt;;;;;;;;:;:;;;;;;:;;;;;:;;;:;;;;;;;;:;:;;:;;:;:;:;::;;:;::;:;;;:;:,;;:;;;;;;:;:;;:;;:;:;:;::;;;;:;:;;;;:;:;;:;;;:;:;;:;;:;:;:;::;;:;:;:;:;:,;;:;;;;;:;:;;:;;:;:;:;::;;:;:;:;;:;:,;;:;;:;;:;;;:;:;;:;;:;:;:;::;;:;:;:;;:;:,;;:;;:;;:;;::;;:;:;:;::;;::;:;:::;::;;;;;;;:;:;;:;:;::::::;::,;:;;.1,cAR E ELECTHONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONIC'S ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS 'J AYCAR ELECTRONICS ,J AYCAR ELECTRONICS 1JAYCAR ELECTRONICS JAYCAR ELECTRONICS ,J AYCAR ELECTRONICS .JAYCAR "E°LECTROI ELECTRONICS JAYCAR ELECTRm ELECTRONICS JAYCAR ELECTRm ELECTRONICS JAYCAR ELECTRm ELECTRONICS JAYCAR ELECTRm A ELECTRON I_CS JAYCAR__fLfCIRQNLC_ s_JAY.CAB....ELEC.IB.ONIGS JAYGAB El ECTBONI C S IAYCAB El ECIRONICS IAYCAB FI FCIBOMICS IAYCAR FI FCTPOI\IICS IAYCAR FJ FC'TROP>.IICS IAYCAB El Errso~ , R ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ,R ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYC AR ELECTRONICS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR \A ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ,A ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS . AYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ,RELEcT- ~, .. -- .. .. -· --· - - ---· ·· - - .... -·- -·- ---- .. - - .... - · --·--- -- ··-- .... ----·--- - - .. ·-- ... - · --·-- - - - .. ·-- .... - · --·--- --.. ·-- ... ·- · --·- · --- .. _ ·• .. - · IA f'LFC ::mg :: ELEc ~t~g ,.• 1A ;~ itig . IA ELEC ,A ELEC ,A ELEC IA ELEC ,A ELEC :: ELEC ~t~g •· IA \R FLFC ffiE~c ,R l LcC ,H cLEC ,R ELFC ,A ELEC ;: ~~~g ,R ELEC ;; · : .· :~g~:t ~g:: ~: .vcAR EI STEREO AUDIO MIXER <at> □ m[})C\Ov0 ~ <at> QOv[})QOv0 Brand new model ~g;~ This mixing console is packed with features. II combines the qualities of a broadcasting or mixing console with the features _ _ _ _ _ _ _ _ _ ___.,, , YCAR E ~;,dii~~t :itsc jockey, sound amateur or home mixer. Will accept Inputs from microphones, turntables, tuners, tape decks, FEATURES • two microphone inputs • 4 stereo inputs • level control for each stereo input• VU meters, headphone socket • 240 volt operated SPECIFICATIONS Inputs Sensitivity Impedance ~, Mic 1 & 2 1mv 600n .,. Phono 1 & 2 3mV 50kn Line 1 & 2 150mV 100kn Outputs- Amplifier oulpul - max 3.SV rms (1 kHz) • Recording output - max 3.5V rms (1kHz) • Headphone output 200mW Frequency Rasponsa • Mic - 20Hz - 20kHz ±2dB • Phono - 20Hz - 20kHz (RIM) ±1 dB • Line - 20Hz - 25kHz ±2dB Slgnel to Noise• Mic - 60d8 • Phono - 60dB • Line - ?OdB THD • Mic - less lhan 0.1% • Phono - less lhan 0.1% • Line - IP.ss than 0.05% Dimensions • 382(L) x20(XW) x 75(H)mm Cat. AM-4202 YCAR YCAR YCAR YCAR &g EL::C EL=C •A FL=C 1R f LcC ,A ,R •A EL::C 1R FLEC ,R EL::C ,R E'LcC ,R ELC:C ============:::;;-i',] ~~~~~ ~ YCAR : YCAR t STEREO AUDIO Mll:ER with YCAR YC,\R 1c Equaliser, Auto Talkover and sound EFFects rCAR F YCAH, C,.\R f YCAR YCAR YCAR m □ m [}) C\Ov0 ~ <at> QOv[})QOv0 19" RACK MOUNT • Ideal for professional DJ's etc SPECIFICATIONS• same as AM-4202. • Dimensions 482(L) x 200(W) x 75(H)mm. Standard 19' rack mounting. Cal. AM-4208 $24 · ~ =:-~=:---l}--::;;~ - •·:.- :_-. ' , ~ 4 ii ] !!!l1r :;:T = o="=P=E==:==:==:=E = L=~=TY ==:::::::T\?-11~ 1~= ::..p~=-~ ::::~::: ;:=' •!:::: t :::;:se ::?i~t~·.-~·;:~:;::::::~:::::; :•=:~ r .,= ·• ·• ·~,~::-= •~7·"".& "'-o- c:~:-:-~ 1 I'·, I~ ,R ELEC ,R E:LEC .R E'LEC ,R ELEC R ELfC .R ELEC R El.EC R ELEC R FLFC A E'LE:C R fLEC R ELEC R ELtC R FLEC R FI.EC R FLFC A ccEC R ELcC R cl.FC R FLEC R ELEC R ELEC R ELEC R ELEC A ELcC Teleguard VPS security system These areway below what you would normally expect lo pay. Made in Japan by Japan Piezo Co. They incorporate a stereo headphone (32n dynamic) and a soon dynamic microphone mounted on an adjustable boom with a windscreen. Microphone is dynamic and doesn't requl revoltage lo work. Supplied with stereo 6.5mm plug for headphone and mono 6.5mm plug for microphone. SPECIFICATIONS RecelvlN' • dynamic speaker unit • 32 ohms impedance • sensitivity 95d8/mW • frequency response 20 - 20kHz • nominal input 1mW • maximum input 1OOmW • cord length 2.5 metres Microphone • dynamic pressure gradient lype microphone • bi-directional polar pallern • impedance SOO ohms • sensiilivily -82d8 al 1kHz • frequency response 200 - 5kHz Cal. AA-2023 WAS $179.50 $59.50 ~q WAS $22.95 .38~ .9uce $17.95 SAVE $5 ELEC E:LEC s ELEC l f'LEC 'I :'LEG , ELEC -l ELEC 'I FlFC 'I ELEC , E'LE'C l ELEC , ELfC ' ELEC E E:. El E YCAR E E },•, YCAR • F----..J • J/L,.. Ideal for lhe hobbyist and handyman. Our lowest price 240 volt qualily iron has a stainless steel CaLTS-14SONORMALLY $16.95 .9uu$l2.95 SAVE $4 •~-,r ·"r-\_..! barrel25wall. ,&\~ .,.,.,~ . 'l'i'!!'!l'l'/!a ~. . ~g;~; .IAYCAR SOLDERING IRON ,• ~t .9uu $B9.50 SAVE $20 ,. . •••■■llt===~= ~l fCJRC _. ~ ; ~ ] ~ ~~~g ,•,,•v"",.•,v"!'-:,•a'"',.."!',•v,,_!!'!'!"~'!""!''!'!!'!-'i-'!!"!l'!~--- E E E' QO Cbvwffi~D0Cb8v ~[})<at><at>CuJ 8WW08<at> WAS $109.50 ~-ff_m_~l : q EcfC q ELEC -l 'I c !?uce $129.50 SAVE $50 TRANSISTOR AND eONTINUITV TESTER a~ R El.EC YC;..R L YCAH YCAR YCAR YCAH YCAR Yl:AR YCAR YCAR ) YCAR El • • YCAR E .................................................................... ·•-"- YCAR r YC AR E YCAR E. YCAR E' . YCAR E YC AR E This is an ideal alarm system for home units and small houses. Its easy YCAR E lo operate and Install. Simply screw the unit on the wall. II has an . YCAR E, inbui lt PIR (range up lo 15ml) as well as a 12V rechargable 700mA gel YCAR E1 baller~ The unit requires 12V DC lo charge lhe ballery, a power supply · YCAR E YCAR E· can ti, plugged in permanently or for 10.hours when lhe power light · YCAR F fl ashe~ Iapprox every 2 weeks). II has an inbulll 115dB piezo screamer, YCAR E and w ;., is ii loud, as well as a 12V oulpul socket for an external piezo YC AR E of requ,red. YCAR E Once lhe unit is swilched on by lhe keyswilch !hey keys are then hidden YCAR E YCAR f and r,v, ,ual day lo day on/off operation is by lwo RF lransmiller key , YCAR E fobs. YCAR E This is a well engineered alarm system, ii is easy lo use and install and ii works very well. Its made in Italy and there is only a limited quanti ty. YCAR F Cal LA-5140 YCAR l YCAR ,· ~ YCAR E YCAR E 240V power adaptor to suit 1:lV DC 300mA Cal MP-3006 $15.9 5 YCAR E YCAR i YCAR E YCAR E YCAR f YCAR E See catalogue for lull detai ls YCAR E A pre-buiil, qualify lransislor tester incorporates a continuity lesler wilh a YCAR E Cal. XE-4950 LED and buzzer.Transistor tester checks both NPN and PNP and also YCAR E YCAR E advises if circuit or short ci rcuited. ~ YCAR E YCAR E cat. OT-2250 YCAR E YCAR E YCAR E YCAR E YCAR E YCAR E MICROPHONE R ELEC R fLEC R ELEC A ELEC R ELEC q EL!"C '1 ELEC l ELfC '< ELEC t E EYCAf~ [ 1R ELcC 1R EL~C ,R ELi..C ,9 ELEC E' ' E: FEATURES • two microphone inputs • six stereo Inputs • level control for each stereo Input - swllchable • LED bargraph VU meters • rack mount • lalkover • fader• bass and treble control (Equaliser) • master output volume conlrol • headphone monitor volume control • cue monitor• sound effects - bombing, laser, ambulance, shooting, siren, machine gun, telephone, storm • 240V ,RFIFC R E-LFC R ELFC ,R fLEC E • YCAR !c C ~c:: ~ YCAR YCAR YCAR , ;·CAR , ,R E'L"C ,R fLi=C ~ ~g:: ~ YCAR ,R FLEC 1R FL,C ,A ELcC ,A EL"C ELECTRON ELECTRON ELECTRON ELECTRON -·.EcTRON ,YCAR El YCAR !' YCAR E YCAR £_ YCAR !:. YCAR E ~g::t ~g::~~ 36'e:-/--:',.tm YCAR Ee a~·. ;9;0;N;IC;S; J;A;Y;CA ; ,R ;:;: EL~E;C;T;RO ; ;Nl;C;S~J;AY ;C ; A;R~E ; L;E;C;TR; O ;N ; IC ;S ;; JA ; Y;C;A;R; E;L;EC ;T ; R;O;N;,IC; S; J;A;Y;C;AR~ EL;g;g~I~ l ELECTRONICS JAYCA ~ON1CS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELEC TRONICS JAYC AR ELECTRONI l ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECT lON•CS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONI l ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONI .lONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONI l ELECTRONICS JAYCAR ELECTRONICS JAYC AR ELECTRONIC . . AYl:r.. · . fRONICS JAYC AR ELECTRONICS JAYC AR ELECTRONICSIJAYCAR ELECTRONICS JAYCAR ELECTRONI 1 ELECTRONICS JAYCAR ELECTRONICS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR E[ CTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONI l..£1...EC TBO NICS IAYCAR FI F C TRO fl.!I C S IO Y CAC FI C:CTAOI\. UC S lt' Y COP Cl CC TPO P..UCC: ro vcoo c:1 ccroorncc ,o "c- ,o c:, rcT o oo , ,,,a• r, cr z oo or l\lll..,.:"l .JA f L,Ar\ t:L CV I M Vl'I I I..,,:) .J J,1,, J VM M CLC V I MVl'IIV,:) JM I VMn C: LC: V I nV''I I\.,..;) Jt\ 1 VM.n C:LC:V I nvr1i1 1v,.;i .JM I Vt\n L. L.LV I n v1 1i1 1v~ ..JM I VMl1 L.L.L.V I 11Ullil1VV .JM I VMI l L.L.L.V I l"'IVl~ I VV \J M I Vr'\ 1 1 L.L.LV l I ,u,~,v .... vn I"-''"• NICS NICS "-ICS NICS NICS NICS JAYCAR JAYCAH JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRON ICS ELEC TRON ICS ELECTRONICS ELECTRONICS ELECTRON ICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRON ICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRON ICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRON ICS ELECTRONICS FLECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELEC TRON ICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS E"ECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELFCTRONICS ELECTRON ICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAA JAYCAR JAYCAR ELECTRONICS ELECTRON ICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR :AR ELECTRONics JAYCAR ELECTRONics JAYCAR ELECTRONics JAYCAR ELECTRONICS JAYCAR ELECTRONics JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRO :AR ;AR ;AR :AR :AR ,AR .AR ,AR :AR -AR .AR .AR AR AR AR AH El FCTRONICS JAYC AR ELECTHONIC S JAYCAR ELicCTHONICS J AYCAR ELECTRONICS J AYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS ,IAYCA R Fl FCTRONICS .IA YC:AR ELicC ELEC EL[ C ELEC. ELEC ELEC ELEC FLFC Lists specifications of over 7000 ELEC microprocessor chips including MPU's, ELrC CPU's and support devices ROM's, ELEC EccC· RAM's, PROM's. clocks, VARTS and ELEcC I/0's. ELt C Cat BM-4564 W as $19.95 ::LEG ELE:C ELECELI- C ELEC ELEC ELcC· ELEC E:_cc EcEC See catalogue for full details. E" EC AR AR AR AR AR AR AR AR AR AR AR AR AR AR c . . =c~ AR FLfC 1 AR EL:.C AR ELFCl AR ELECl AR HEC"I AR ELECl AR FlfCl AR FLFCl AR E"EC ' AR c. f-C I AR E_!=Cl AR ELECl AH ::LlCl AR ,LFCl AR ELECl AR Elf-Cl AR ELEC T • AR f-LE Cl AR ELl=Cl AR FlFCl AR I- LEG' AR ELEC" Afl f- LE:C " AR FLFC AR cLEC' AR ELI-C" ELECTRONICS ELECTRONICS ELECTRO NICS FI FC:TRONIC:S g;,,,tleia, /N'ee, $17.95 Cat price $349 : mi: ,R ELECTI :: ~~~g~: ,H F LECTI .R E-Lrc n .R .R R R R R 'CARE JAYCAR MIXER KIT 6 Sector Programmable Alarm Panel Bargain /CAR /CAR /CA R /CA R ICAR 1 CAR g,-,, tl«IP.1 /1"/et$349 BUY10 ~ LESS10% ~ ~&/1/1<at>[1[}'[1' s;t~ UHF ANTENNA PRICES SLASHED We were sick and tired of paying too much !or anten nas. We have lound our own supplier and can now reduce the prices by up to 45%. But don't worry, the new ones are imported but so were the ones they replaced. New everyday low pri ces. Wholesale enquiries: phone (02) 747-2022. 43 Element Spees -Gain: 13d8, Channels: 21 -69, Frequ: 470-862mHz, Boom: 20mm square, Overall length: 1234mm, Finish: elements and boom anod ised. Cat LT-3181 Was $89.50 NOW ONLY $ 49 • 50 2 PIN MAINS LEADS <at>[p[]:<at>0& [1, ONLY $199.50 12 Sector Programmable Alarm Panel Bargain ~ $599 TURN YOUR SURPLUS STOCK INTO CASH!! Below wholesale Jaycar will purchase your surplus slacks of components and equipment. We are continuqlly on the lookout for sources of prime quality merchandise. (02) 743 5222 ';l; ~, ---------·• • r_j.........." · - · i~! . =========si ~:, Ii - MasterCard. =~= ~==') "'I llr' A 5 ~ Can1o ELEC T! _ ,, . . , ELEC T! ELFC TI , , , EL~CTRONICS JAYCAR ELlCTHONICS JAYCAR ELECTRO NICS JAYCA R r l-'11 - SYDNEY • CITY PARRAMATTA RHODES BANKSTOWN GORE HILL 91 Element Don't miss this bargai n. Top quality DMA brand 2 pin moulded mains leads. The cable is grey round with btueand brown inner cable. 240V, 7.5A, SAA approvced. Length 2.75ml. 1. 9 10 · 99 100+ Supplied wi th two alpha numeric remote keypads. Cat LA-5185 now on 'CARE 'CARE 'C ARE 'CAR E 'CARE CAR E CAR El CAR El CAR El CAR El CAf1 El CAR c l CAR El CAR El CARE , CARE , CARE: CARE, CAR El CAR!::. CAR El CAR El CAR El CAR El CAR El CAR El CAR El Save about $200 Call Mark Harris or Bruce Routley E E E E E E •C AR:: See last months ads or call into any store Cat LA-5180 := ~~~g; ,R EcECT !,~~: Don't miss this amazi ng runout sate ol ALL ou r stock of 8, 12 and 16 channel mixers. This includes complete kits and separate modules. See 1991 catalo;iue pages 6 and 7. 20% OFF ALL MIXERS AND MIXER PARTS ,RFLFCT ,H lLlCT ,R E-ECT Cat OC-191 0 Catalogue price $399 Cat price $22.95 Cat KC-5055 \R Fli:-CT \R E- ECT :: ~L~g~ JAYCAR J AYCAR JAYCAR .IAYC:A Quality video/audio RF modulator Studio 1/2 octave Eq kit \R ELECT ,R E, EC T ,R FLFC T ELECTRONICS ELECTRONI CS ELECTRONICS FI FCTR IC:S $ 8.50 ;t"-"'1!, lLlCT fLFCT ~L~CT E'L:'CT ELECT ELECT ELFC T FLFCT FLfCT u !-C' JA YCAR J AYC AR JAYCAR .IAYC:AR g;,,,tleia,/1"1~~ ;H E:.Lt-C-r ,R ELECTRONICS ELECTRONICS ELECTRONICS FI FC:TRONIC:S good strong signal. Full specs supplied. Cat LM 3848 AR f!...EC"" ;R AR \R \R \R \R \R \R ELECTRONICS JAYCAR E:LECTRONICS JAYCAR l=LECTRONICS JAYCAR ELECTRO ELECTRO NICS JAYCAR ELECTRONICS J AYCAR ELECTRONICS JAYCAR ELECTRO ELECTR ONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS J AYCAR ELECTRO FI .T CTRO CARE CARE CAR E CARE CARE VH F unit swilchable to Aust Ch 3 or 4. The audio is pl aced at the See catalogue tor tull details C ARE correct subcarrier frequency and output lrequency is stable with TOWERS MICROPROCESSOR SELECTOR BOOK AR [LE Cl ARE FCl AR l-LECl ,;R [LE Cl AH ::LlCl AR cLFCl AR FL c CT AR ELECT AR E.FC T AR cLECT AR HI Cl AR ELECT AR cLECT AH LLLCT AR ELEC T AR EL'cC AR ELECT AR ELEC T AR F. FC T AR fLFC T \R EU, Cl ,R J AYC AR JAYCAR J AYCAR .IAYC: AR 11.50 1.35 1.00 f I = Spees - Gain: 15-19dB, Channels: 21-69, Frequency: 470862mHz, Boom: 20mm square, Overal length 2214mm, Fini sh: elements and boom anod ised. Cat LT-3182 Was$139 NOW ONLY m7]i $79.50 Em ~~--~~¥tf\\ ~lsSJ' ==1-1G14:C DOUBLE SIDED FIBREGLASS BOARD ·"' 365x 210mm Cat HP-9520 Cat price $14.95 g,-,,,tkla,/"'he, $5.00 t$.:!, HEAD OFFICE 6Leeds St reetRh odes 2138 Telephone (02) 743 5222 FAX (02)743 2066 ::AR El ::AR El ::AR El ::AR El CAR El CAR El CAR El CAR El CAR El CAR El CAR El CAR El :: AR El ~AR El ::AR El ::AR El ~AR El ::AR El ::AR El :AR El : AR EL :AR EL :AR EL ,AR EL - AR EL : AR El : AR EL :AR EL :AR E. : AR EL :AR EL :ARE , • :AR E. : AR EL : AR EL : AR EL : AR EL : ARE , :AR E. :AR EL ;AR EL ;AR EL ' AR E, ARE POST & PACKING 24 -99 3.75 $1D -_$ $ 4.50 $25 $49.99 $ PO · · Bo x 185C on co r d 2137 FREE CALL • FOR ORDERS DNLY AREL AR EL $50 _$99.99 OVER $100 ROAD FREIGHT ANYWHERE IN AUSTRALIA (up to 20kg) $13.50 :: $ 6.50 $ 8.00 11 7 York SL(02) 267 1614 Mon-Fri 8.30 5.30 Th urs 8.30pm - Sa t 9 - 1 355 Church St (Cnr. Victoria Rd) (02) 683 3377 Mon-Fri 9 - 5.30 Thurs 8.30pm - Sat 9 - 4pm :~:~~~ ~~a~;,4;4~ 5222 Mon-Fri 8.30 -5.30 -Sat 9 -1 2 363 Hume Hwy Cnr Meredith SI (02) 709 2822 Mon-Fri 9 - 5 30 Thurs 8.30pm- Sat 9 - 4 - Sun 10 - 4pm 188 Pacilic Hwy (Cnr Bellevue Ave) (02) 439 4799 Mon-Fri 9 - 5.30 Thurs 8.30 - Sat 9- 4pm AR E~ BURANDA QLD COBURG VIC (008) 022 888 HOTLINE (02) 743 6144 144 Logan Rd (07) 393 0777 Mon -Fri 9 - 5.30 Thurs 8.30 - Sat 9 - 4 266 Sydney Rd (03) 3841811 Mon-Fri 9 - 5.30 Fri 8.30 - Sat 9 - 4 ~~3 MELBOURNE CITY ~hi::;i :5-~s;i~::1:.~~i\~3~ 2030 SPRINGVALE VIC 887-889 Springvate Rd Mutgrave (03) 5471022 ADELAIDE SA ~~ AR EL AR E 'AR E~ AR EL ,;: ~~ AR EL ;~~ i~ : ARE - Nr Cnr. Dandenong Rd Mon-Fri 9-5. 30 Fri 8. 30 - Sat 9 - 2 :AR EL 190 Wrigh t St (Cnr. Se lby SI) (08) 231 7355 ;:: ~L Mon-Fri 9- 5.30 Fri 8.30-Sat 9-1 2 : AR EL :AR EL : rno~ ._ ,_ , v,.,, vv v n, vn LLLV,, v141 v v .J M, v n n ,_ v I vPi1r vv vl"'I r v l"'l n CLCV nv1'1' 1v v J M I v,-..n C L Cv I nv, 11 1v 0 J M r (..,f'\ri C LCi..., / n ,._.if '-i"{\,., ,J ,ir. i\JM.1 , LLL v ,1 , v ·,111.;_,._, .Jri. • .;_,;.,;,, .._.._LCTROf\ ELEC TRONICS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS J°AYCAR ELECTRONICS JAYCAR ELEC TRO NICS 1J AYCAR ELECTRONICS JAYCAR ELECTRO~ ELECTRONICS JAYC AR ELECTRONICS JAYCAR ELECTRONICS JAYC AR ELECTRONICS JAYCAR ELECTRO NICS JAYCAR ELEC TRONICS JAYCAR ELECTRONICS JAYCAR ELECTRO~ ELE CTRO NICS J AYCAR ELECTRONICS JAYC AR ELECTRONICS J AYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS jJAYCAR ELECTRONICS JAYCAR ELECTRO~ A i= 1 1=rTAnl\11rc: 1Av r110 c1 c:f"'Tnf"'\"11r- c- 1 /\ \lf"' /\n r, r r-TnA"11r-0 111 H r-"n r- , r-r,Tn""~",...("' ,,. ., ,...,.,..._ r- , r--r-T,..,,..,..,.,...,... ,. ,, ,... ..... ,..., .... ,... ....... .... . .. .... AMATEUR RADIO BY GARRY CRATT, VK2YBX Build this simple turnstile antenna for weather satellite reception Interested in listening to signals from the polar-orbiting or geostationary weather satellites? This simple antenna can be built for -a few dollars yet will give good results. Most amateur operators appreciate that, for ground based communications , vertically polarised antennas with a low angle of radiation perform best. By stacking dipoles vertically, the radiation pattern is compressed so that the usable "gain" is radiated towards the horizon , thus theoretically encompassing any receiving stations located on the ground. Conversely, for airborne communications, an antenna having a higher angle ofradiation is desired, since the signal must be radiated upwards instead of hugging the ground. The same applies for the reception of weather satellite signals. The easiest weather satellite signals that can be received using simple equipment are those radiated by the polar orbiting APT satellites. These satellites broadcast circularly polarised signals located around 137MHz and have typical output powers of DIPOLE 2 / FEEOPDINT '-DI )J4 PHASING LINE Fig.1: basic layout of a turnstile antenna (groundplane not shown). It consists of two 1/2-wavelength dipoles mounted at 90° and fed 90° out of phase. Note the 1/4-wavelength phasing line used to feed the second dipole. about 5W or so. Due to their polar orbit, they pass quite close to the Earth's surface at heights ranging from 110-BOOkm. The signals received on Earth from these satellites are much stronger than those received from geostationary satellites, which orbit at 37,000km. In any case, the optimum antenna for the reception of weather satellite signals is one which combines circular polarisation and a high angle of radiation. The turnstile antenna This photograph shows the general construction of the turnstile antenna. The reflector was made from small mesh chicken wire attached to a wooden baseplate, while the dipoles consist of threaded steel rods attached to a wooden mast. A right-angle metal bracket is used to secure the mast to baseplate. Although a simple groundplane antenna having a 1/4-wavelength radiator can be used in applications requiring a high angle of radiation, a far more useful antenna is the "turnstile" - so named because of its resemblance to a supermarket turnstile. A turnstile antenna consists of two 1/2-wavelength dipoles mounted at goo and fed goo out of phase. When mounted above a suitabl e reflector as NOVEMBER 1991 53 This close-up view shows how the dipole elements & the phasing harness are fitted to the mast. The threaded rod dipoles make it easy to attach the phasing harness using solder lugs & nuts. shown in one of the photographs, the radiation pattern fulfils both our requirements (see Fig.2). The response of the antennc!, directly above th e dipoles is circularly polarised, while at angles between 45° and 0°, the response is elliptically polarised. In this regard, the reflector spacing is an important consideration, as it determines both the radiation pattern and the feed point impedance of the antenna. Reflector spacing As can be seen from Fig.3, if the reflector spacing is increased from 0.22 to 0.37 of a wavelength, the vertical response is reduced while the response at lower angles (30-50°) is improved. A further consequence of this reflector spacing is that the characteristic impedance of each dipole is very close to 100 ohms. In order to feed the two dipoles out of phase, they must be connected via a 1/ 4-wave phasing harness. Fig.1 shows this arrangement. As with other phasing harnesses, the physical length of the harness is reduced below a 1/4wavelength according to the velocity factor of the coaxial cable used. By selecting a 0.37 wavelength reflector spacing, this arrangement can be fed with standard 50-ohm coaxial cable, thus greatly simplifying the construction compared with other reflector spacings requiring a matching section. In practice, the antenna response is also improved for receiving polar orbiting satellites. The accomp anying photographs show the general construction of the antenna. The reflector can be made from small mesh chicken wire or phosphor-bronze m esh, while the dipoles can be made from aluminium tubing or steel or brass rods. To protect it 1 Fig.4: this diagram shows the dimensions required for a 1/4wavelength phasing line. SILICON CHIP Fig.3: increasing the reflector spacing of a turnstile antenna to 0.37 wavelength reduces the vertical response but improves the response at lower angles (30-50°). This makes the antenna suitable for satellites passing at relatively low angles but still gives useful pickup for satellites passing almost directly overhead & for geostationary satellites. Construction 260mm 54 Fig.2: shown at top is the typical radiation pattern from a groundplane antenna, while immediately above is the pattern for a turnstile antenna with a reflector spacing of 0.22 wavelength. Note the dramatically improved vertical response of the turnstile antenna. from the weather, the entire antenna should be sealed using "Estapol" or some other plastic paint/sealant. As constructed, the antenna has a modest gain of around 6dB , which is quite sufficient for the reception of polar orbiting weather satellites. Also, there is no specific requirement for the antenna to be elevated to any great degree above the ground, so long as the "view" is largely unobstructed from about 20° above the horizontal. We built the prototype out of scraps of "chipboard" and softwood planks. However, for a long-lasting antenna, chipboard is no good as it deteriorates rapidly in wet weather. If you want it to last, use good quality timber and These photographs show the results that can be obtained by connecting the turnstile antenna to suitable receiving equipment. All four images are from GMS-4 but you can also tune into the polar-orbiting satellites. prime and paint it for weather resistance. The main mast, which holds the dipole elements in place, is centrally located on the baseboard by a right angle bracket, available from most hardware stores. The dipole elements are made from zinc-plated threaded steel rods and are connected to the coaxial cable using solder lugs. Mounting the dipoles The dipole elements are mounted by drilling horizontally through the mast at 10mm intervals. The elements are then mounted by passing them through the timber and securing them using steel nuts and washers. Another advantage of using this method is that the 1/4-wavelength phasing section can be pre-fabricated on the workbench. We used heatshrink tubing to seal the jacket of the coaxial phasing section. As the fe ed point impedance of the dipoles at 0.37 wavelength reflector spacing is about 100 ohms, the phasing line must be made from 75-ohm coaxial cable. Fig.4 shows the dimensions of this part of the antenna. The coax feed can be standard 50ohm type and solder lugs are recommended for the connections to the dipoles. The reflector uses two overlapping layers of small diameter chicken wire, available from most hardware stores (as is- the threaded rod). As this wire is only available in 900mm wide strips, a total length of 2.6 metres is required to cover all of the base plate. We used galvanised staples to secure the wire to the baseboard and overlapped the screen to give the fullsized reflector dimensions. Perhaps this simple antenna, which can be used with an inexpensive scanning receiver or a modified 2-metre receiver, will encourage readers to further explore the world of weather satellite reception. Just to whet your appetite, we have included several photos of full-screen video pictures, obtained from the more sophisticated GMS weather satellites, just to show the remarkable results that are possible. Of course, you'll need some extra equipment in addition to your scanning receiver to obtain pictures like these , including a computer interface and, possibly, a video printer. We'll have more to say about this in a future article. In the meantime, have fun tuning into those satellite signals. Further reading (1). Australian Electronics Monthly, July 1986. (2). The ARRL Antenna Book. (3). Weather Satellite Handbook, by Ralph E. Taggart. SC NOVEMBER 1991 55 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. Three-way quiz game uses relays & diodes In the July 1991 issue of SILICON CHIP, there was a quiz game based on three 555 timers. This circuit uses four relays and does not need any ICs at all. The relays and some diodes provide the logic. It works as follows. If button Sl is pushed, relay RLl is energised via diode Dl. This will then latch up via its normally open contacts and lamp LPl will light. At the same time, relay RL4 is energised via D4 and it disconnects the three pushbuttons from the+ 12V rail and hence prevents the other players from participating. The buzzer also sounds for a short time while the 470µF capacitor charges. The circuit then remains in this disabled state until the normally closed reset button S4 is pressed, to unlatch the relays. No on/off switch is required since no current flows in S4 ~ L I I I I I I I I I I I I I I I I I I I I I ) I I I I I I I I I +12V I I 04 1N4DD1 • I 07 1N4001 the circuit until a button is pressed. Caution: with this design, it is possible to have a dead heat whereby more than one contestant gets his or her lamp to light but this would be a difficult condition to obtain. F. Kemsley, Coolangatta, Qld. ($30) o.,rn S2a 02 47Dn BC547 AMPS M1 E~ 10 + 25VW LED1 POWER I \ \ 3.3k 05 1N4004 270k L_______________________ J Low-cost variable power supply This power supply circuit uses readily available parts and can deliver from 3-24V at currents up to 3A. Power for the supply is derived from the mains via transformer Tl. This drives bridge rectifier Dl-D4 and a 4700µF electrolytic capacitor to give a 26V DC rail. This is then fed to adjustable regulator REGl which in 56 SILICON CHIP turn drives current amplifier Ql. VRl sets the output of REGl and thus the voltage on Ql's emitter. QZ and its associated relay RL Yl are used to light a LED if the fuse blows. Normally, when the fuse is intact, QZ and the relay are on and LED 2 is off. However, if the fuse blows, QZ turns off, the relay contacts close and LED 2 turns on. Finally, meter Ml is used to provide voltage and current readings. When the AMPS range is selected, the meter measures the voltage across the 0.1 H2 current shunt resistor and indicates current. When the VOLTS range is selected, Ml is switched in series with the 270kn and 47kQ resistors and indicates the output voltage. The 0.110 shunt resistor can be made by connecting three 54mm lengths of 0.32mm resistance wire in parallel. R. Parnell, Blacktown, NSW. ($25) r-------.---......-------------1------- -----+-------•l2V 03 1N4148 FORWARD PINS IC3c 14 1M ::>o~ll-+~'W--"f ;:IC>"-+--, IC3 5 D 4013 IN AAILPOWER CONTROLLER S 6 REVERSE 1----INh--+-f Ol-'- 3 ~0"---9 CLK TO PIN 3 OF IClc PIN1 IC3d A 7 4 _9 S1 ~ov FORWAR~ Speed sensitive direction switch One drawback of the Railpower train controller (p,escribed in SILICON CHIP, April and May 1988) is that it allows the operator to reverse the direction of the train at high speed. This drawback applies to most other train controllers as well. This circuit overcomes that problem and works as follows. When the voltage from the train controller is lower than the reference set by VR1, clock pulses from IC2d are gated through flipflop IC3 and any direction changes you make are transferred directly to the output relay. However, if the train controller voltage is above the reference, the oscillator (IC2b & IC2c) is disabled and any changes in direction made using S1 will not be echoed by the relay. In greater detail, comparator stage ICl has its reference voltage derived from VR1 , while the non-inverting input is fed from the train controller. The lMQ resistor between pins 1 & 3 provides some positive feedback to produce a "snap action". IC2a inverts IC1 's output anq this in turn controls the oscillator via Dl. When IC2a's output is low (ie, when the controller voltage is above the reference), D2's cathode is pulled low via a 10kQ pull-down resistor and the oscillator is disabled. IC3 is a dual Dtype flipflop. An SPDT switch (S1) is used as the direction control and provides either a high or low data (D) input. Thus, when no clock pulses are being received by IC3, any attempted direction changes will have no affect on the actual direction of the train. Conversely, when IC2a's output is high (ie, the r.ontroller voltage is lower than the reference voltage) , D2's cath- 04 Power supply for portable valve radios Old-style valve portables have lots of charm and are usually excellent performers. Unfortunately, running them from batteries is a costly exercise and that's assuming that one can obtain the batteries in the first place. The solution is this mains-derived supply which can either be built as a free-standing unit or fitted into the space once occupied by the batteries . It produces a 1.5V DC rail to power the valve filaments and a 90V high tension (HT) supply. The power supply consists of a multi-tap 2155 transformer feeding a fullwave rectifier (Dl & DZ) and a 2200µF filter capacitor. The resulting DC supply is then fed via a 10Q resistor to an LM317 adjustable 3-terminal regulator. Trimpot VRl is adjusted to provide an output of 1.5V. ode is pulled high, the oscillator is enabled, and clock pulses are fed to the flipflop (IC3). Thus, any direction changes set by S1 will immediately be clocked through to IC3's Q output at pin 1. IC3 's output in turn drives transistor Ql via a 22kQ resistor. When IC3's output is high, Ql turns on and the relay pulls in. D3 prevents any back EMF spikes from damaging the transistor when the relay turns off. The circuit should be powered from a regulated +12V supply (eg, use an ancillary 7812). The input voltage is derived from the positive side of the inertia capacitor, or from the wiper of the speed potentiometer in controllers without inertia. Finally, the relay contacts take the place of the existing forward/reverse switch on the controller (S2 in the Railpower). Graham Palmer, Auckland, NZ. ($25) 1N4004 ,on 3W 2200 + 16VW _ 2200 16VW 0.1 0.1 100 + 16VW _ + _ 05-08 E+ 4x1N.4004 12V 240V 56k 3W The multi-tap transformer also provides 4.5V to drive transformer T2 backwards to give 90VAC. This then drives bridge rectifier D5-D8, a lOOµF 100 350VW + _ capacitor and an RC decoupling network to give the 90V DC rail. G. J. Sones, Box Hill South, Vic. ($20) NOVEMBER1991 57 GREAT SIGHTS AND SOUNDS FROM ROD IRVING AND ARISTA COMPONENTS PROTECTORS & SUPPLIES TOOLS & TECHNICAL G2 ~ ~-""-=w..='-4 COMPONMENT RETRIEVAL KIT TWO PIN MAINS ADAPTOR Convert• ., lwo pin U.S or European plug into an Australian two pin plug. Designed for use with double i11 sulated appliances Approval#: N11071 P18012 ............................................ $4.95 FAX, PHONE, COMPUTER, MODEM, PROTECTOR. 240VAC/50HZ MAINS & PHONE LINE PROTECTOR X10089 ......................................... .$59.95 This unique unit has been developed to offer the maximum posaible external protection to the user equi pment such as fax machines, computer modems & teleph one answering machines. Bo th the phone lines and main power inputs are protected. The CPEP1 helps to reduce damage to equ ipment connected to the telephone network when subject t o lightning strikes and mains power spikes end surges. DESIGN IEC CHASSIS MOUNT SOCKET WITH INTERFERENCE FILTER. Protects instrumentation etc. from EMI (Electro magnetic Interference) that can upset or destroy data t ransmission . • 3 pin IEC male chassis socket. • 250V-6 •mp • Approval No. CS32193N P10255 ..........................................$19.95 / --,~~ --- •StatuaDiaplay:Red neon indicates "power on " , green neon indicates "correct earthing contact"and amber indicates ''faulty wir ing" requ iring attention. -Power lnput/output: plug &socket arrangement allows lnline installati on. •Line input/output:Dual US modular telephone sockets used for connecting the fax, telephone answering machine, modern etc . PROTECTION: • The unit uses a combination of M.O.V. and gas arrestor ciru itry lo prevent damage to home and office equipment thus eleiminating down time and costly repairs. •Approved by the Australian Dept of Minerals and Energy. •Aproved #: n11361 't:-,,i., . PREPAINTED ALUMINIUM CASES x (H)46mm x(D)65mm H10141 ..........................................$10.95 •Dimensions:(W)110mm x (H)SOmm x (D)S0mm H10142 ..........................................$13.95 •Dimensions :(W)140mm x (H)56mm x (D)110mm H10143 ..........................................$17.95 •Dimensions:(W)180mm x (H)56mm x (D)130mm H10144 ..........................................$23.95 •Dimensions:(W)230mm x (H)56mm x (D) 140mm H10145 ..........................................$32.95 These brilliant new universal kit boKea are supplied with screws, brackets and rubber feet. Each panel has been scored so it can be folded once only to form the cabinet walls. Each unit ha• anodised aluminum panelo thot are designed to be painted, the top and bottom also has air vents for cooling. They are available in five different sizes ideal for kits and projects and are flat packed for easy storageand display. PLASTIC / ALUMINIUM r REESTANDING BOX SIZE:110W X 140L X 46H Silver/ grey cabinel with aluminium front panel. •Screw assembled case with screwhole for mounting PCB'• H10146 ............................................$8.95 T12084 .. .......... .......................... ... $10.95 $ PLASTIC VICE WITH SUCTION BASE Medium sized vice ideal for holding parts and components during soldering or glueing. -Stong sution base adheres to any non po~ous surface. •Lever secures or releasessuction •Plastic jaws wrth rubber pad s .Jaws open out to 50mm •Size:Approx 110 x90 xao T12459................~··········.$6.95 HANDSFREE MAGNIFYING GLASS FOLDING MAGNIFYING GLASS Free standing magnifing glass. •Allows hands free operation •large 115mm (4.5") Leno •Folds completely flat for storage T10020 .........................................$13.95 . •Dimensions :(W)SOmm Supplied with two fu lly insulated tweezers and long flexible finger with a magnet on the end. Allows small components and to be picked up or manipulated in small, narrow hard-to-get.at places UN-INTERRUPTABLE POWER SUPPLY 500 WATT UN-INTERRUPTABLE POWER SUPPLY X11112 ........................................$1399.95 A Stand•by regulated power supply ayotem. •Designed for computer systems and re lated peripherala. •Provides protection against blackout, brown outs, voltage fluctuati ons, power surges, spickes and line noises. •Monitors 240 volt AC supplied to the system and removes any voltage tran sients and fluctuation prior to directing it through to the equipment. If AC power fluctuates beyond an acceptable level the UPS500 switches from normal to backup mode and continues to power the equipment wiyh its own internal backup mode and continues to power the equipment with its own internal backup batteries until the AC power is returned to normal. at this point the UPS500 ret urns back to no rmal mode and proceeds to recharge its -- batteries. •Audible alarm buzzer sound when unit transfers to backup power. th is provides a warning to make backups or ahutdown the computer system before any damage or data losscan occur. Buzzer can be manually turned off oncethe situation haa been diacovered. •Approved by the Australian Dept of Minerals and Energy SPECIFICATIONS: Output Rating (Under Load ): 500 watts Voltage Unit Switches To Backup: 204 and 260 vo lts AC Voltage Unit Switches To Normal: 212 and 252 volts AC lnpuUOutput Frequency: 50Hz or 60Hz Typical Rechsrge Time: 10.12 Hours Responce Time : 4mS (typical) /Sms (max) Voltage Regulat ion: + I .5 % Aud ible Alarm: Buzzer and LED Indicators Overload Proleclion : 3.15 amp Internal DC Fuse: 40 amp Dimens ions : 144 x 242 x 436 mm Weight: 20.5kgs Safety: According tolEC 380 AS3250 ROD IRVING ELECTRONICS Pty. Ltd. ACN .005428437 HEAD OFFICE: 56 RENVER RD, CLAYTON . PH: (03) 543 2166. FAX (03) 543 264B CITY 48 A'BECKETT ST. MELBOURNE. PH. 663 6351 / 639 1640. FAX : 639 1641. NORTHCOTE 425 HIGH ST. NORTHCOTE, PH. 4B9 8866. FAX : 489 8131. SYDNEY:74 PARRAMATTA RD, STANMORE. PH: (02) 519 3134. FAX: (02) 519 3868 BLUESTAR COMPUTERS : 271 MAROONDAH HWY. RINGWOOD. PH: (03) 870 1800 ALUMINIUM TORCHES Battery size:1 xAA ............................ Not Supplied A15066 ..................................... $ 9.95 Battery size :2xAA ............................ No1 Supplied A15068.......................................$10.95 Battery size :3xAA ......................... . .. Not Supplied A15067........................................ $11.95 Machined "Aircraft Allu min ium" flash lights. •Lena case unscrews and doubles as a free standing torch base. •Adjuatable lens varies ! he beam from a spollight lo flood light. -Rubber water resistant "O" rings. •Replacement globe stored in base of the torch. RECHARGED KEY RING TORCH Miniature handheld torch designed specifically for the car. It comes with a 'quick-click' removable keyring which allows remival of your car keys whi le recharging. The torch utilizes a nickel cadmiumbattery Swhich can be recharged aerveral hundred times. this can be done at any time, even while drivi ng as the to rch body itself is shaped to fit directly into the cigsrette lighter s ocket. Ideal for use with cara,trucks,boats and other 12 volt negative earth vehicles. The unrt is made of s sturdy black plastic, comes complete with a keyring and push button operated A15070 ....................................... $11.95 Postage rates $1 • $9.99 ...... $3.00 $10 • $24.99 .. $3.50 $25 • $49.99 .. $4.50 $50 - $99.99 .. $6.00 $100 • $199 ... $7.00 $200 - $500. .. FREE $500 PLUS .. FREE Th•• pootago rate ■ are bHlc pootage only up to : ~ky ~o;:;~:lght, 118 mo wtll be charged at different •• 18 • TOLL FREE MAIL ORDER HOTLINE: 008 33 5757 IBM CARDS FLOPPY DISK DRIV.E SPECIALS! 1.44MB 3 1/2" 1 ·9 10+ $105 $99 1.2MB 51 /4" 1·9 $129 10+,,, $119 XT HO CONTROLLER. ........ $129 AT HO CONTROLLER ......... $1 69 RS232/SERI AL CLOCK........ $49 MONO COLOUR CARD ....... $76 MULTI 1/0...••.••••.•...•.•...••.. ..... $99 VOICE MAIL. ...............•.•....$199 PRINTER CARD .................•.. $29 EGA CARD..........................$1 79 DIOGNOSTIC......................• $795 FAX CARD........................... $595 4 PORT SERIAL ................. $199 2 WAY FOO CONT (360K) ..... $39 RS232/SERIAL CARD ..•...... $39 Lets you connect a normal telephone handset and a fax to the same telephone line. • Detects whether an incoming call is for the phone or fax and automatically puts it through to the correct unit. • It automatically switches when you pick up the phone or use the fax to make an outgoing call. SAVE $20 this Month! ). GAMES CARD ....... ..... ......... $29 AT S/P/G 2 S/P/G.................. $49 4 WAY FDD CONTROLLER (360·1.44M) .......................... $129 2 WAY FOO CONTROLER (360· 1.44M) ........................... $80 CLOCK CARD ...................... $39 VGA CARD 8 BIT 256K .........$89 VGA CARD 16 BIT 250K (EXP TO 1 MEG).................. $229 VGA CARD 16 BIT 256K (EXP TO 1 MEG).................... $99 VGA CARD 16 BIT (1 MEG )............................... $199 SMART DRIVE ADAPTER IDE/FDC.............................•... $49 512K/576K RAM CARD ......... $99 X19090 ............. $269 RITRON MONITOR rofessional loo k! 11102 ............$199 Power supply to u it (220w) ...... $199 MOTHERBOARDS Both for $295 TOPOFTH I RANGE MINI : TOWER . CASE • · 00 x 415 x 330mm Nith 200w power supply )(11100 ........ ..... $249 NEyv MINI TOWER CASE WITH P.S 11103 .............$149 RITRON EXECUTIVE CASE nciudespowers upp~ 11089 ............. $119 - SUPA VGA COLOUR MONITOR 3 .YE.A.R WARRANTY This stylish & reliable monit or has been designed tor Austra lian conditions & comas with a 3 year warranty. Spees: CTR : 14" 90° deflection, dark•tint , non•g lare. Display Size: 245+/5mm x 180+/•5mm Resolution: (max): 1024 x 768 Dot Pitch : 0.28" 286· 12/16......................$159 286· 16/21 ...................... $199 386SX·10/20 ................. $350 386SX·20/27 .................$375 386·33 WITH 64K CACHE ........ .......... $750 386·33 WITH 128K CACHE ............... $895 386· 40 ..........................$795 486SX ·20 ................... $1195 rWHAT'St--H~-Vl?, fWHAT'S NEW?, \=tD {~ TECMOUSE MOUSE HOLDER Microsoft serial & PC mouse compatible (serail Version) • Stylish & ergonomic design gives a unique feeling of pleasure & comfort in your hands. • Feature touch button control • Stream•lined design, glossy finish • Smooth well•balanced glidinq, Handy mouse holder ~ ttachas to Iha side of the I computer or monitor for ~toring a mouse w hen not 1 In use. It Is supp li ed j with adhesive velcro so l the mouse holder can be j easily removed from the : computer or monitor if 1 required. Will accept a : mouse with maxim um 1 demensions of 65mm 1 j wide & 35mm thick j I C21064 •••••••••••••• $3.95 AMAZING $29.95 S er: FREE SPACE QUEST 1 with every Sound Blaster II. The All-in-One s ound card. Sound blaster II is the ultimate sound board that easily plugs into any internal slot in your IBM' , PC, XT, AT, 386, PS/2(25/30) & compatibles. FEATURES: • Text to Speech synthesizer • 11 vioce FM Music • Digitized Voice Input & Output. • Midi interface • Built-in joystick port • Power amplifier & Volume Control • Bundled software : SBTALKER with Dr SBAITSO VOXKIT .voice development t ools Talking Parrot FM Intelligent organ L----------------~ I On ly................ $269 SOUNDS BLASTER PRO -· -·-·· ·,<'1·i USING MS-DOS 5 The most helpful DOS book available has now been updated for DOS 5 so you can achieve DOS success in easy steps. Real world analogies and examples guide you to confidently write batch files and Macros. Includes a DOS survival guide giving trouble• shooting advice. ffl.$51.00 USING WORDPERFECT 5.1 11111---1 2nd EDITION . Discover the secrets to success for over 100 000 users I This classic best seller expertly leads you from basic techniques to advanced Word Perfect operations, with detailed coverage of all new features . ...................... $57.95 • 16 Bit card • Stereo DAC with hardware ADPCM • Stereo Recording for line-in and CD-Audio • Stereo 22 voice FM music Synthesizer • Ml DI interface CD-ROM Interface built-in • Text to Speech Driver. • Secectable IRQ and OMA • Power amplifier built-in Bundled Software: Ml DI Adaptor & sequencer FM Intelligent organ VEDIT: Voice editor & Utilites CD Music player MMPlay Presentation Advance to power user status with hands-on exercises for learning Windows basics. Then customize your aystem using usful tipa. This handy reference also teaches you Windows Paint & Windows Write. Only.................. $469 ......................$51.9 USING MICROSOFT WINDOWS3 r-- THIS MONTHS GA I X14532 ................ $489 1 AN SOU. TEAii - \. PHAXSWITCH JAPANESE DRIVE SPECIALS SOUND BLASTERS !THEIR FINEST HOUR .•••••••...... l sEARCH FOR THE KING.•.. j UNKS CHALLENGE GOLF. !ELVIRA.................•.....•......... IJET SET PACK. ••••..•••••........ jKING'S QUEST V•................ !SECRET OF MONKEY IS j HEART OF CHINA•.............. 1RED BARON.........••............• 1TEST DRIVE 11... ............... . ECIALS PC TALKING VOLTMETER, PT.2 Because most of the work is done by the computer, the PC Talking Voltmeter is a fairly simple device. This month, we give the full construction & adjustment details. By DARREN YATES The PC Talking Voltmeter is built onto a PC board coded SC07110911 and measuring 136 x 58mm. Before starting construction, check the copper side carefully for any breaks or shorts between tracks. If you find any, use a dash of solder or a sharp artwork knife to fix the problem. 60 SILICON CHIP Once you're happy with the board, start construction by installing PC pins at all external wiring points - see Fig.3. When these are in place, install the wire links and the resistors. Note that 1 % resistors are used in the input voltage divider network, as indicated on the wiring diagram. Table 1 shows the resistor colour codes. Alternatively, you can use your multimeter to check the resistor values before installing them on the board. The diodes, ICs and capacitors can now all be installed, followed by the two 3-terminal regulators. Check the regulator type numbers carefully before installing them on the board, so that you don't get them transposed. The 7905 is mounted with its metal tab towards the adjacent lO0µF capacitor, while the metal tab of the 7805 goes towards the edge of the board. You can now complete the PC board assembly by installing transistor Ql. Orient the transistor as shown and push it down onto the board as far as VOLTMETER INPUT it will comfortably go before soldering its leads. Wiring A plastic zippy case measuring 150 x 90 x 50mm is used to house the PC board and its associated hardware. The PC board mounts on the lid of this case and can be used as a template for marking out and drilling the four mounting holes. Once the holes have been drilled, the board is secured in position using machin e screws and nuts, with four nuts used as spacers. The adhesive front panel label can now be secured to the base (ie, the base becomes the front panel) and holes drilled to accommodate the LED, input sockets and rotary switch. You will also have to drill three holes in one end of the case (adjacent to the rotary switch) to accommodate the power switch, a 3.5mm power socket and an optional RCA output socket (if you intend connecting the PC Voice Recorder). It's always best to drill small pilot holes first and then carefully ream each hole to its correct size. The various switches and sockets can then be mounted in position and the wiring completed as shown in Fig.3 and the photographs. Two 4mm banana sockets are used as the front panel input terminals (red for positive and black for negative). Take care when wiring up the rotary switch as it's easy to make a mistake here. The same goes for the LED wiring. You can identify the cathode lead by the adjacent flat area on the LED body. It's also the shorter of the two leads. A 10-way length of ribbon cable about 3-metres long can be used to wire up the DB-25 connector. This job H m = ® Q- I" --mo-. --<at>J-o ~;;; TO PCVOICE - - - RECORDER-!__ GNO - I 1 12VOC - - PLUG-PACK+:---!-,. 03 ' • 07 555 100uF - ~ .... 100uF 01 TLD74 :; 1 ~ ---nm:J-. ';' ...... ..._. 79!~ •I . = 0B25 -<at>D-o ~ ~ ~:<at>: OiaC2 ~~ • ~ ., ---<t::::),4 ~ 100uF : OO EB c3 ..J',.. ~N ,..._._...---....... OA~6soo ' 06 .____. •G CONNECTOR •2 •3 •4 •5 •6 •7 •8 •9 •10 •19 04 0 LED1 Fig.3: here's how to wire up the PC board. Take care to ensure that all polarised parts are correctly oriented & note that the five resistors in the input voltage divider (immediately below IC2) are all 1 % types. is straightforward - just make sure that you connect each wire to the correct pin on the back of the connector (the pin numbers are moulded into the plastic insulation) . The printer port cable emerges through a slot filed in one end of the case (see photograph). This also involves filing a slot in the lip that runs around the inside edge of the lid. If necessary, you can make the cable longer than the 3-metre length specified but don't go beyond about 6 metres. · the voltmeter board to the output marked "pin 14" on the Voice Recorder board (see wiring diagram on page 42 of the August 1991 issue). The output of the voltmeter is thus fed into pin 3 of IC4a on the PC Voice Recorder board via an 82kQ resistor and 0.lµF capacitor. Note that, in this mode, the input section of the PC Voice recorder is not used. Nor do you have to make any connections between the PC Voice Recorder and the parallel printer port. In addition, the playback section of PC Voice Recorder is now controlled by the software that's used for the PC Talking Voltmeter. Connecting the Voice Recorder As mentioned previously, only a 2wire connection is required between the PC Talking Voltmeter and the PC Voice Recorder. One wire simply connects the two circuit grounds (GND) together, while the other runs from Testing Before plugging the cable into the printer port, connect the plugpack supply and check that the supply TABLE 1: RESISTOR COLOUR CODES 0 0 0 0 0 0 0 0 0 No. Value 4-Band Code (5%) 5-Band Code (1%) 1 1 2 1 3 6 1 1 680kQ 220kQ 180kQ 100kQ 10kQ 4.7kQ 2.2kQ 820Q not applicable not applicable not applicable brown black yellow gold brown black orange gold yellow violet red gold red red red gold grey red brown gold grey black orange brown red red black orange brown brown grey black orange brown brown black black orange brown brown black black red brown yellow violet black brown brown red red black brown brown grey red black black brown NOVEMBER 1991 61 The photo at top left shows the opening menu when you run the software. You can select any one of seven options by pressing the spacebar and then pressing return. The photo at bottom left shows the display when you select the "Basic Voltmeter" mode. In this case, the screen is displaying the voltage from a fresh 9V battery. voltages to the ICs are correct. If you don't get the correct voltages, check the plugpack polarity and for incorrectly oriented ICs and regulators. If the supply voltages are OK, you can now test the board by first connecting a 50kQ pot. (anywhere from 10-300kQ will do) across the ±5V rails. This done, connect the pot. wiper to the positive (+) input, plug the cable into the printer board and boot up the software as described in the· following section (ie, type "GO" and then hit return at the DOS prompt). Select the "Basic Voltmeter" mode from the on-screen menu and check that the front panel LED flashes continuously. If you now vary the pot, the on-screen reading should change. Don't worry at this stage if the reading isn't accurate. This will be fixed when you go through the following setup procedure. Software The software for the PC Talking Voltmeter is available from the author and comes on a 5.25-inch 360Kb floppy disc (see parts list). Included with this disc are the full running instructions and a programming guide as well. y Y 128 I I I I I I I I I I +12.8 ·12.8 · I ·127 ACTUAL CONVERSION : SLOPE WRONG INTERCEPT WRONG I I STEP 1 : CORRECT FOR Y-AXIS INTERCEPT I I STEP 2: ADJUST SCALING Fig.4: this diagram shows how the conversion slope & intercept are adjusted so that we get the correct reading. The X-axis represents the input voltage, while the Y axis represents the 8-bit code from the computer. 62 SILICON CHIP PARTS LIST 1 PC board, code SC07110911, 136 x 59mm 1 360Kb disc with VOLT.BAS software (see panel) 1 plastic zippy box, 150 x 90 x 50mm 1 adhesive front panel label, 151 x87mm 1 DB25 male connector 1 3-metre length of 10-way ribbon cable 1 4-pole 3-position rotary switch 22 PC pins 2 4mm banana sockets 1 set of probes with 4mm banana plugs 1 3.5mm power socket 1 panel-mount RCA socket Semiconductors 1 DAC0800LCN 8-bit DAC (IC1) 1 TL074 quad op amp (IC2) 1 555 timer IC (IC3) 1 7805 +5V regulator (REG1) 1 7905 -5V regulator (REG2) 1 BC548 NPN transistor (01) 1 5mm red LED & bezel (LED 1) 4 1N914 signal diodes (D1 ,D2,D7,D8) 4 1N4004 diodes (D3-D6) The PC board is mounted on the lid of the case, while the input terminals, rotary switch & LED are mounted on the base which thus forms the front panel. Use a 3-metre length of 10-way ribbon cable to wire up the DB-25 connector. When you boot up the software, you can choose any onP. of four diffP.rent operating modes: (1) a basic 8-bit voltmeter with onscreen digital readout; (2) an 8-bit voltmeter that interfaces to the PC Voice Recorder project; (3) a data logger that records volt- age measurements over tim e with adjustable time intervals; and (4) a graphic display mode for data logged measurements. Each of these features, plus the voltage reference setup, can be selected from the main menu. The software is easy to drive. You boot it up by typing "GO" and then hitting return at the DOS prompt. After that, it's just a matter of selecting the required operating mode using the spacebar and return keys, and then making sure that the selected onscreen voltage range matches the setting on the voltmeter. Reference setup A slot must he filed in the inside lip of the lid, together with a matching slot in one end of the case, to provide clearance for the printer port cable . Before you start using the PC Talking Voltmeter, you must first go through the voltage reference setup procedure by selecting it from the main menu. What we've done is to use the computer to store a reference voltage and apply a scaling factor so Capacitors 4 100µF 25VW electrolytics 4 0.1 µF 5mm-pitch metallised polyester Resistors (0.25W) 1 680kQ 1% 1 220kQ 1% 2 180kQ 1% 1 100kQ 5% 1 10kQ 1% 2 10kQ 5% 6 4.7kQ 5% 1 2.2kQ 5% 1 820Q 5% Miscellaneous Hookup wire, tinned copper wire , screws, nuts, washers etc. Where to buy the software The software for the PC Voltmeter, VOLT.BAS, is priced at $35 + $3pp and includes running instructions and documentation . All software come$ on a 5.25-inch 360Kb disc and will run on any PC with at least 256K of RAM and a parallel printer port. Payment should be made by cheque or money order to: Darren Yates, PO Box 134, French 's Forest, NSW.2086. Note: Copyright of the software is retained by the author. NO V EM BER 1991 63 The display shown at top left is presented when you select the "Setup Procedure" from the opening menu. As before, you select the required option by pressing the spacebar & this then gives the display shown at bottom left (note: the voltage shown here is for illustration only). After that, it's simply a matter of following the on-screen instructions. that we get the correct reading. After you select the "Setup Procedure ", you are presented with a second screen that gives step-by-step instructions. You simply select the 12.8V range , connect the input lead to the output of the +5V regulator, press return twice, disconnect the input and press return again. The +5V reference voltage is then stored as an 8-bit code in a small file called VOLTSET.BAS. If the output of your 5V regulator is a bit off, you may like to substitute another into the circuit. Alternatively, you could try an LP2950ACZ 5V regulator IC. This comes in a TO-92 transistor type package and has an initial voltage tolerance of about o. 5 % . However, you should find that most 7805 regulators will do the job just as well. So long as your reference diodes give a voltage of about 1.3V and your 5V regulator is within ±50mV of 5V, the voltmeter will be quite accurate. Fig.4 shows how the scaling process works. Here, the X-axis represents the input voltage and the Y-axis represents the 8-bit code from the computer. Because the scaling factor is linear, the transfer function is simply a straight line. All we need to do now is (1) adjust the intercept (where the line crosses Fig.5: check your PC board carefully against this full-size artwork before mounting any of the parts. 64 SILICON CHTP =UflJlll/JI/J= =IUIIJI'!- PC TALKING VOLTMETER Fig. 7: this fullsize artwork can be us·e d as a template for marking out the front panel. + • + A/D STATUS ±1.28V • • ±12.SV ±128V VOLTAGE RANGE + + + WARNING: Check screen for voltage over-range the Y-axis); and (2) adjust the slope of the transfer function so that we get a 1:1 ratio. Fig.4 first shows the initial conversion from the ADC. The fact that it doesn't intercept zero and has the wrong slope can be caused by a number of factors. This problem is Use PC stakes at all external wiring points on the board, to make the wiring easier. Note the orientation of the two 3-terminal regulators. solved when you initially go through the setup procedure. When you go through the setup procedure and press return with the input disconnected, you are setting the OV reference. We can now add the difference between the two codes to get the correct OV reading. Fig.4 also shows how we get the correct reading for each point on the scale. During the setup procedure, we set the conversion factor of the LSB to 1 OOm V, so that the difference between a OV reading and a 5V reading should be 50. Ifwe get something else, then it is just a matter of scaling by the ratio of the two readings. This may sound complicated but the software takes care of it all for you. You can verify the final result by monitoring the input to the PC Talking Voltmeter with a digital multimeter. When you compare the meter reading with the on-screen voltage, you will find that the two readings are remarkably close. SC NOVEMBER 1991 65 COMPUTER BITS BY JENNIFER BONNITCHA Modifying the Windows INI files Last month, we talked quite a bit about the Windows PIF Editor and introduced the subject of Windows INI (initialisation) files. These effectively set up Windows in the way you want it, each time the system is booted. During your forays through Windows, it should be apparent that it takes some time to get the applications, desktop background, colours, fonts and so on just the way you want them. Don't let a little experimentation get in the way of your day-to-day computer use - make sure you backup at least the WIN.IN! and SYSTEM.IN! files before you start playing around with them. Thus, if fc1-te strikes, you can restore the backup copies to the Windows subdirectory and save yourself a whole lot of trouble. Remember, you have been warned! A basic but overlooked trick is to load an application as .Eile .!;,dit .S,earch !::!.elp [boot) 286grabber=ugacolor.gr2 386grabber=uga.gr3 fixedfon.fon=ugafix.fon oemfonts.fon=ugaoem.fon fonts.fon=ugasys.fon display.dru=tpd19.dru shell=winfile.exe network.dru= language.dll=langeng.dll comm.dru=comm.dru sound.dru=sound.dru mouse.dru=mouse.dru keyboard.dru=keyboard.dru system.dru=atmsys.dru atm.system.dru=system.dru [keyboard) subtype= type=4 oemansi.bin= keyboard.dll= Fig.1: Although it's usual to load the Program Manager when Windows initially starts, you can load other utilities instead by editing the SYSTEM.IN! file. In this example, the statement shell=winfile.exe automatically loads the File Manager when Windows starts. 66 SILICON CHIP an icon when you start Windows (similar to "preselecting" the application). WIN.IN! is an ASCII file which you can edit with any word processor; eg, the Windows Notepad or Sysedit utilities, or even good old EDLIN. It contains several sections, as described last month and, within these sections, statements representing the function's setting. Many of the sections correspond to the Control Panel icons and so are easy to change from within Windows itself. Other sections containing font, configuration and dictionary location, for example, are included or updated during application installation. Some, like the LOAD and RUN statements in the [windows] section need to be changed manually. You could, for example, make the following entry to automatically load Winward as an icon when Windows is executed: [windows] load=c: \ winword \ winword.exe In other words, the appropriate Program Group will be activated (probably Windows Applications) and the Winward icon automatically selected. Thus, you could choose to start Winward simply by double clicking on the already selected icon, or you could choose some other task. On the other hand, the next entry in the WIN.IN! file would not only select the icon but would also start the program: [windows] load= run=c: \ win word\ winword.exe You can load and run several programs at the same time, provided names are separated by either a single space or a comma, eg: [windows] load=vp. pif run=c: \ win word\ winword.exe pbrush.exe You are limited to 127 characters in total per line, although this should be sufficient for most needs. Thus, you can have your favourite application(s) load and run every time you start Windows and you can start either Windows or Non-Windows applications using this E.dit .Search .!:f elp [windows] load= run=c:\pm4\pm4.exe Beep=yes Spooler=no HullPort=Hone deuice=PostScript Printer,PSCRIPT,FILE: BorderWidth=3 KeyboardSpeed=31 CursorBlinkRate=530 DoubleClickSpeed=452 Programs=com exe bat pif Documents= DeuiceHotSelectedTimeout=15 TransmissionRetryTimeout=45 swap disk= .Eile [Desktop] Pattern= (Hone) , Wallpaper=gray.bmp TileWallpaper=1 GridGranularity=O IconSpacing=100 [Extensions] cal=calendar.exe A.cal crd=cardfile.exe A.crd trm=terminal.exe A.trm txt=notepad.exe A.txt ini=notepad.exe A.ini pcx=pbrush.exe A.pcx bmp=pbrush.exe A.bmp wri=write.exe A.wri rec=recorder.exe A.rec c~r=c:\coreldrw\coreldrw.exe A.cdr pm4=pm4.exe A.pm4 pt4=pm4.exe A.pt4 tbl=TE. exe A. tbll Fig.2: by suitably modifying the WIN.INI file, you can either automatically load a program as an icon or load & start one or more programs when Windows is executed. This example shows how to automatically load & run Pagemaker 4 (ie, run=c:\pm4\pm4.exe). method. Choose either the executable file name or the name of the program's PIF file. A word of warning - if you can't run in 386 enhanced mode and you choose to run more than one full-screen DOS application, only the last one will open full screen. If you change a setting incorrectly in the SYSTEM.IN!, Windows may become disabled next time the program is started. Most settings in the file should be changed via the programs supplied with Windows - ie the Control Panel , etc. Remember also that the text files, WININI.TXT and WININI2 .TXT, together with SYSINI.TXT, SYSINI2.TXT and SYSINI3.TXT, are present in the Windows directory to supply you with furthar information about the .INI files. When fate strikes (or you change your files beyond imagination), backup copies of not only the main .INI files but all .INI files in the Windows directory would be helpful. The two standard files are by no means the end of the Windows information files. The PROGMAN.INI file for ex- ample, stores the configuration of all the Program Groups you have created, while the .GRP files contain further information about each Program Group - such as the location and name of each Program Item's executable file in that particular Program Group. System shells The Program Manager is usually the first thing seen when Windows starts, as it's the utility provided to select and start applications. When Windows is initially installed, there are three pre-defined groups - Main, Accessories and Games - although you can add more if desired. To this end, you could edit the SYSTEM.IN! file so that the File Manager loads automatically instead of the Program Manager: [boot] shell=winfile.exe This statement automatically loads the File Manager when Windows starts. There exists a distinct advantage in starting Windows using this method, as you can start an application and particular data file from an icon or by double clicking on a data file. Quick starts The [extensions] section of the WIN.IN! file contains settings linking groups of files with applications so that opening one of the files automatically starts the application. For example: xlw=excel.exe A.xlw xlc=excel. exe A.xlc dot=winword.exe A.dot doc=winword.exe A.doc pcx=pbrush.exe A.pcx The A symbol tells Windows to associate all files with the following extension to the application shown; eg, all .DOT files are associated with Windows Word. This is not to say that you can't use that file type with other applications, merely that if you double click on a file with that extension, Windows will automatically start Windows Word. Automatically opening a specific data file and its application relies on the information contained in the [extensions] section. If you need to associate many files, you will find it quicker to edit the WIN.INI file. Another method is to run the File Manager. Suppose you want to associate .DAT files. To do this, open a directory containing files of this type, select one, then choose the File Associate command. Type the drive, path and filename of the required program's executable file in the dialog box, then press Enter or click OK. Thus, from the File Manager, you an can start an application by double clicking on the name of either an executable file or an associated ~ata file. Depending on the application, this may be more convenient than opening the required Program Group, then selecting the required icon, etc. Multiple program items Each Program Item in a Program Group is a Windowsdefined object containing enough information to tell Windows how to find and launch an application and optionally load a particular file. This presents another alternaNOVEMBER 1991 67 Modifying the Windows INI files •••••••••••••••••••••••••••••• tive to using the File Manager - create Program Items which also load a particular file. If you need to, associate the data file as described above. Now switch to the Program Manager, select a group for the new icon, then choose File New Program Item OK. The Description is up to you; supply a name for the icon and, on the Command Line, type the drive, path and filename (including extension) of the data file. Change the icon if you want to, then choose OK. Since the contents of a group do not depend on your disc's file structure, you could have a Program Group called MOST USED and have diverse operations like WordPerfect, Ventura, Excel and Harvard Graphics ready at hand. Frequently-used files could be called by their associated icon, rather than loading the application and then opening the required file. You can edit any Program Item using the File Properties command. Typical examples could be users with cardfiles and calendars that need to be loaded frequently. Rather than loading the application and then opening the appropriate file, the file can be automatically loaded by copying the icon and changing the File Properties. You can move or copy an existing Program Item from one group to another. Start by opening all the required group windows and, if you like, use the Program Manager's Window Tile command to place them side by side. Move a Program Item by dragging its icon from one window to another. To copy the Program Item, just hold down the Ctrl key while you drag the icon -you may want to start an application from more than one Program Group, or you n;ay want to load a different file. If you change your mind, click to select the required icon then press the delete key. You are only deleting the icon, however, not the associated program or data files. Program switching You can quickly change from one open application to another using the Switch To command. Sometimes applications become "lost" when they are minimised - well, not lost really, but hidden under the Program Manager group. An easy way to find these applications without resizing your windows is to place the mouse pointer anywhere on the desktop's background (where no application is running) and double click (or press <Ctrl Esc> at any time) to activate the Task Manager window. A list of all active applications appears so you need only double click on the one you want, or click to select then click on Switch To. Alternatively, pressing <Alt Tab> toggles you between the two most recently used programs. You can also use it to cycle through every active program - just hold down the <Alt> key while you keep pressing the <Tab> key. When the required window, icon or menu bar appears, release the <Tab> key and you're in business! SC Protect your valuable issues Silicon Chip Binders These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers & are made from a distinctive two-tone green vinyl. They hold up to 14 issues & will look great on your bookshelf. * High quality * Hold up to 14 issues * 80mm internal width * logo printed in gold-coloured lettering on SILICON CHIP spine & cover Price: $All.95 plus $A3 p&p each (NZ $A6 p&p). Send your order to Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy Beach, NSW 2097; or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number. Use the handy order form included in this issue 68 SILICON CHIP CJ-118A 20MHz Dual Trace Osc;i.l.lc,sc;c,pe SPECIFICATIONS: Operating modes Yl, Y2, Yl and Y2 added are swltchable alternately and Intermittently. Bandwidth, MHz: ■ DC coupled input: at -3dB .. 0-20 ■ DC coupled input: at -6dB .. 0-35 ■ AC coupled input: at -3dB .. 3x10·'-20 ■ AC coupled Input: at -6dB .. 2x10·'-35 ■ input with external divider In position 1:1 .. 0-7.0 Transient response built-up .time, ns, max.: ■ DC coupled Input: .. 17.5 with external divider In position 1:1 .. 50 Deflection factor (11 -callbrated steps with 1-2-5 seq.) ■ ■ mV /DIV: ■ Accuracy,%: ■ Max. input (AC/DC) V: .. 5-10' .. +/- 4 .. 250 Input Impedance, Mohm/pf: ■ ■ ■ DC coupled input: with external divider In position 1:10 with external div ide r In position 1:1 .. 1/20 .. 10/15 .. 1/100 Sweep speed (21 calibrated steps with 1-2-5 seq.) ■ ■ ■ ns/DIV: Accuracy,%: 50ns/DIV+ Accuracy,%: 20ns/DIV .. 20-50x10' .. +/- 4 .. +/- 8 Trigger modes: ■ Auto, turning to triggered upon application of trigger signals HOPM (NORM). Trigger source: ■ Dimensions: 212 x 133 x 336mm Screen Size: 4" Includes 2 x 1:1 10:1 probes, and screen protection cover. Internal (from channel Yl or Y2), external. Sensitivity for Internal synchronization, V: ■ ■ 50Hz to 4MHz, DIV., Max.: .. 0.8 4MHz to 20MHz, DIV, Max.: .. 2 Sensitivity for externa l synchronization, V, Max.: ■ lOHz to 20~ ·'-lz .. 0.2 Typical exte-.. ·I synchronization ■ Input Imp. kohm/pf Note: for Go vernment Dept's, Schools, Sales Tax No. holders, etc only $430.43 ea. (ex -tax) - official order must be produced .. 70/15 · Available from: .·.·. iJavidReid Electronics Universe Computers · 127 ._ York Street . 127 Melbourne St, . . . ·.. . . SYDNEY N.S. W. 2000 Nth ADELAIDE S.A. 5007 Ph:{02Jg6jfa85 Fax: (02/2618905 Ph: /08/ 2391577Fax: (OBI 2391221 (Mailor.d e r s welcome ) (Mai/orders welcome} supercomputers being developed for the market and bring together leading experts to focus on future commercial applications in Australia. The conference will be held at Bond University on the Gold Coast from December 2-5. A 2-day workshop will precede the conference and a trade exhibition will run at the same time. For further information, contact the Convention Secretariat, PO Box 1280, Milton, Old 4064. Phone (07) 369 0477. Automatic 4-way printer switch This Auto Printer/Sharer allows up to four computers to share the one printer or plotter. In AUTO mode, the unit scans the inputs for incoming data. When data is detected, it locks out all other inputs until the file is printed , then restarts scanning . In manual mode, any input can be selected. Front panel LEDs show wh ich input is in use. The unit retails for $190 and is available from Electronic Solutions, 2/5 Waltham St, Artarmon , NSW. Phone (02) 906 6666. Genius hand-held scanner The GS-4500 hand-held scanner can transfer graphic images such as photos , drawings and text directly to your PC. It is capable of scanning an image up to 105mm wide in one pass or 300mm wide in several passes using a m~rge function. There are two modes, letter or photo. Image resolution is controlled by a slide switch , with ranges of 100, 200, 300 or 400 DPI (dots per inch). The level of brightness is adjusted via a rotary dial. Contrast and scan widths are controlled by the Scan-Edit software. 70 SILICON CHIP The photo mode scans images that contain up to 32 shades of grey in three ranges, from a light shade to a dark shade. The letter mode scans in black and white. This is used for artwork and text. Text files can then be converted to word processor readable form by the optical character recognition (OCR) software. Different word processor formats are supported. Also included with the software is the Genius paint and drawing program, Dr Genius. The scanner is connected to the PC through an expansion card that is address and interrupt selectable. The package retails for $299 and is available from Rod Irving Electronics, 74 Parramatta Rd, Stanmore, NSW, or from their Melbourne stores. EGA flat-panel touch modules Lucas Deeco has released a series of electrolum inescent flat panel touch modules. The M6435ST features a 640 x 350 pixel EGA display with 80 x 50 touch points. The infrared touch system connects directly to any serial port. Unlike hardwired consoles , it can be reconfigured at any time with software to meet changing applications. The modules have an operating temperature range of 0-55°C and have onboard self-test and diagnostics. A standard RS-232 port with selectable baud rates provides interfacing with the host. For more information, contact Amtex Electronics, 13 Avon Rd , North Ryde, NSW 2113. Phone (02) 805 0844. Australian conference on super computers The world's most powerful super computer technology will be on show on the Gold Coast in early December. The Fourth Australian Supercomputer Conference will examine the latest Toshiba T2200SX notebook computer This new TS2200SX Notebook Computer from Toshiba uses a 386SX processor in a slim A4-size format which folds to a package only 41 mm thick. In the past, portable computers have presented problems when it came to connecting them to large corporate computer networks and workstations. Toshiba claim to have solved this and the unit can be networked with all major operating systems (such as the popular IBM AS400). This has been brought about by a series of adaptors which allow the Toshiba Notebook to become part of .any information system environment via Ethernet or Token Ring adaptors or linked through IBM 3270 or 5250 emulations. Data security has also been addressed with the release of a product called Customloc. For further information on the TS2200SX Notebook and its networking adaptors, contact Lesley Maclennan, Information Systems Division, Toshiba (Australia) Ltd , 84-92 Talavera Rd, North Ryde : Nsw 2113. Phone (02) 887 3322. 6Mb RAM card for PC compatibles This high-capacity RAM card features high speed, zero wait state operation and low power consumption. Either 4 x 256Kb or 1 x 1Mb DRAM chips may be DSP card for PC compatibles used to support up to 42Mb of EMS memory (with seven boards in the system) or up to 15Mb extended memory in protected mode (286 and 386 machines) . Included is a software driver and other utility programs such as a RAM disk and a printer spooler. The set-up program is menu driven for ease of installation. The memory card is fully EMS and LIM 4.0 compatible and can be configured for either 8 or 16-bit operation. With no RAM chips fitted , the card sells for $299.00 from Rod Irving Electronics, 74 Parramatta Rd, Stanmore, NSW. PC-based programmer card This Sunshine programmer card supports virtually any EPROM in the range from 2716 to 27512 (CMOS and MOS EPROMs are also catered for). The software is menu driven and allows the EPROM contents to be checked before and after programming. Small production runs can be made by use of a batch file and a diagnostic facility allows the programming voltages to be tested as well as all pins on the ZIF socket. Included in the software is a program to convert fi les from hex to binary ; different hex formats are selectable, as well as a 2-way and 4-way file splitter, for 16 and 32-bit systems. The programmer is fast, easy to use, and retails for $275. For more information, contact Electronic Solutions, 2/5 Waltham St, Artarmon, NSW. Phone (02) 906 6666. The DSP-560 digital signal processor from Boston Technology uses the Motorola DSP 56001 processor and has onboard analog 1/0. It comes with 24Kb of high speed static RAM, expandible to 96Kb. The AID circuitry allows software selectable 12-bit (at 400kHz) and 16-bit (at 100kHz) resolution, while the onboard 16-bit D/A converter is connected to a 7th order active filter for output of sampled data. The filter may be bypassed. Host access to the processor, memory and onboard peripherals is via the DSP 56001 's specialised host/OMA interface. This allows high speed transfer of captured , generated and processed data between the card and the PC to be handled automatically. A system expansion interface permits direct serial communication with other peripherals. Demonstration software and source code are included, but optional packages provide advanced development tools for programmers. The DSP-560 is also compatible with the Hypersignal DSP software that supports the DSP 56001 . For more information, contact Steve Mackay at Boston Technology, PO Box 415, Milsons Point, NSW 2061. Phone (02) 955 4765 or fax (02) 922 1118. High performance graphics engine The Chromatics CX2X00 is a configurable high-resolution graphics system that operates on a wide range of host computers, such as VAX, Sun, IBM, SEL Gould and others. Peripherals include a keyboard, digitiser, mouse, valuator, light pen , touch screen , joystick, trackball , bezel keys and a switch box. The systems are all based on the X, GKS and PHIGS+ (PEX) graphics standards and are available either as graphics generators or as complete graphics workstations. Available software includes performance-oriented graphics languages with fast Window performance (up to 32 windows), simultaneous X and highperformance graphics , and a custom microcode development package. Improved drawing performance is assured by the system's use of industry standard languages. · For more information , contact Trace Technology, 200 Rouse St, Port Melbourne, 3207. Phone (03) 646 5833. Optical modem for noisy environments r The HK-3310 optical modem allows RS-232 data transmission in electrically noisy environments over distances up to 1km, using fibre optics. Because the transmission medium is via light beam, the signals are immune from electromagnetic interference. The modem supports full duplex with a bit rate up to 64Kb/s asynchronous and 19.2Kb/s for a synchronous system. It has low power consumption and has an operating temperature range of -20°C to +70°C. For further information, contact Anitech , 52/2 Railway Parade, Lidcombe, NSW 2141. Phone (02) 749 1244. SC NOVEMBER 1991 71 An error analyser for CD players, Pt.3 This month, we conclude our series of articles on the CD error analyser by giving the constructional details. We also show you how it is connected to typical CD players. By STEPHEN McBRIDE If you haven't already realised it, this is definitely not a project for one who is just starting out in electronics. While the construction of the CD error analyser itself is relatively straightforward and no more complicated than, say, a digital frequency meter, you also have to make connections 72 SrucoN CHIP inside your CD player. And that means you have to know what you are doing. But before we go into how the connections are made, let us discuss the construction of the CD error analyser. As shown in the photos in this and the two previous articles, the CDEA is built onto two PC boards housed in an attractive low profile case which is readily available (Jaycar Cat. HB5915). A third PC board is housed inside the CD player, to make the buffered connections to it. Most of the connections between the two PC boards are made by simply butting them together at rightangles and soldering the adjacent pads. Before you start assembling the boards, it's worth spending a few minutes ,with a continuity tester to check there are no shorts between adjacent tracks, especially on the display board where many of the tracks are closely spaced. Once that is done, install the 14 wire links on the main board using tinned copper wire- see Fig.3. Stretch the wire slightly before cutting it into lengths so that the links are straight. GROMMET I Fig.3: the main wiring diagram for the error analyser. Be sure to use insulated mains-rated hookup wire for the bypass link at the bottom left of the board & take care with component polarity. An on-board power supply is shown here but you can also wire the board to accommodate external supplies. The link for the overflow indicator can be installed in one of three positions , depending on how many digits for the interpolation readout are desired. The holes are marked on the PC board as '4', '5' & '6' while the common is marked 'OF'. Just link the 'OF' pad to the appropriate hole. Next mount the resistors and diodes, paying particular attention to the orientation of the diodes. The 74C926's aren't cheap so it is worthwhile fitting IC sockets. Take care not to form a solder bridge between adjacent pads. Don't use a socket for the MOC3041 optocoupler; it is soldered straight in later (if used). The 7-segment displays are mounted in sockets. These can be proper IC sockets or a row of Molex pins. As noted previously, the display PC board mounts at right angles to the main PC board. Rather than just form a solder bridge across the adjacent solder pads, I fitted right-angle wire links for added stability. These links were pulled out of 0.1-inch right-angled PC board pin launchers. Once the two boards are butted together, tack solder the two outermost end pads, then check that the boards fit into the case correctly. If they don't, re-melt the solder and adjust the assembly until a proper fit is obtained. Once you are satisfied that all is well, finish soldering all the others. Again, be careful of solder bridges forming between adjacent tracks. Now install the capacitors and transistors, paying attention to the polarities. Note that Q4 is a PNP type BC328 while all the others are NPN types (BC338). If the Farnell transformer is used, it can now be fitted, making sure it is pushed down snugly against the board. Likewise the heatsink can now be fitted and it too should be pushed in tight. Use a large tip on your soldering iron to solder the heatsink lugs to the board; remember that it is a heatsink and so it will naturally draw a lot of heat away from the pins. Give it ample time to cool as it will be very hot after soldering. Now bend the leads of the 7805 regulator slightly so it sits flat on the heatsink. Remove the 7805 . wipe a smear ofheatsink compound over the back surface of the regulator and refit it. Fix it to the heatsink using a screw & nut, then solder in the leads to the board using a fine-tipped iron. There's no need for a mica insulator pad. Now the two ribbon cables can be fitted if the 5 or 6-digit option is used. Note that the two cables cross over each other. Follow the wiring diagram (Fig.3) for the connection details. Four PC stakes are also fitted where indicated. Two are used as a manual counter reset by shorting them together, out only when the automatic reset facility isn't implemented. The other pair, when shorted together, inhibit the MUTE control line from disabling the counters, so both counters will register counting when a search function is implemented (ie, track jumping), thus verifying that the counters are operating correctly. This NOVEMBER 1991 73 Fig.4: this is the wiring for the satellite PC board. It is connected to the main board in the error analyser via a 6-way shielded cable while the remaining external wiring points go to the CD player (see text). MUTE 2 MOTE1 6-CORE _ SHIELDED CABLE Ii D pair is marked 'TEST' on the PC board. Diodes Dl-D7 and DlO are for protection purposes. D13 is used to match the brightness of displays 9 & 10 to displays 1-8. Without it, non-standard value resistors would be needed. The front panel is a piece of neutral gray filter acrylic cut to size by deeply scoring a line, then breaking it away from a 220 x 130mm sheet. Be careful not to scratch it during handling. The lettering was put on using standard white Letraset®, which is available from drawing office suppliers. Satellite PC board Fig.4 shows the assembly details for the satellite PC board. This is connected to the main PC board by a 6- core shielded cable. If you wish, you can hard wire the two together, but I chose to fit a 7-pin DIN socket to the rear panel of my CD player, and have a flying cord from the CDEA fitted with a matching 7-pin DIN plug, so that the two units can be separated. Drill two holes in the back panel of the instrument case to suit the power and data cables, and install rubber grommets. Feed the cable through the grommeted holes and solder them to the appropriate holes on the PC board. For the 240VAC cable, the Brown wire is Active, Blue is Neutral and Green/ Yellow is Earth. For the data cable, the colour combination is not critical; just be sure that you're consistent. Important: don't connect any of the data wires, especially the shield, to the metal shroud of the plug/socket as you would normally do; to do so would mean connecting the OV rail of the CD player to its chassis and this could cause damage. To help prevent accidental contact with the 240VAC mains tracks on the PC board, place a strip of insulation tape on the inside of the case over the ventilation holes directly under the transformer primary terminals and mains input terminations. Now screw the main PC board into the bottom half of the instrument case and attach the cable restraints to the two cables. Don't fit the LED displays or ICs into their sockets yet. The satellite PC board can now be constructed by following the component overlay diagram. The lOkQ linking resistors at the inputs to the comparators must be fitted to suit the polarity of the tapping points in your CD player. The requirements for the inputs to the main PC board are: UNEC and HFD inputs are normally low and go high when an error occurs; MUTE is normally low and goes high during searching and/or track jumping, pause etc; FCO is normally high and goes low to initiate a counter reset on startup. Connecting the CD player The main & display PC boards are soldered together at right angles & are mounted behind a neutral gray acrylic filter inside a plastic instrument case. Take care when installing the mains wiring. 74 SILICON CHIP The fun part is finding the correct places to tap into the CD player's circuits to pick off the required signals, assuming that the machine you have has the necessary tapping points. A service manual, or in some cases just the circuit diagram, should have sufficient information for you to locate the appropriate tapping points. Remember, each manufacturer has their own terminology and abbreviations or jargon, and they also have different ways of performing the decoding process. The names, titles and abbreviations used in most of this text are all based arounp. the Philips chipsets, and are intended to be used as generic rather than specific terms. Philips themselves use SMSE, MUSB and MUTE to mean 'MUTE', depending on which generation of chipsets is being referred to. As another example, the line marked 'DEFECT' on the Sony CXA1081S (pin 21) appears to be the same as HFD. Most manuals provide a cross- Table 1 · DEVICE PACKAGE DEVICE DESCRIPTION SIGNAL NAME DIRECTION PIN No. TDA5708 28-pin OIL 28-pin OIL 28-pin OIL HFD HFD HFD HFD PLLH HFD Output HI TDA8808 SAA7010 Photodiode Sig. Proc. Photodiode Sig. Proc. Demodulator, Decoder 19 10 6 SAA7210 SAA7310 SAA7310 SAA7000 SAA7020 40-pin 40-pin 44-pin 18-pin 40-pin OIL OIL QFD OIL OIL 40-pin 40-pin 44-pin 24-pin 28-pin OIL OIL QFP OIL OIL HFD HFD HFD UNEC UNEC UNEC UNEC UNEC UNEC FCO HFD HFD SAA7210 SAA7310 SAA7310 Deco.der, ERCO, CIM Decoder, ERCO, CIM Decoder, ERCO, CIM lnterpolator, Muting CIRC Error Corrector Decoder, ERCO, CIM Decoder, ERCO, CIM Decoder, ERCO, CIM Digital Filter, CIM Input HI Input HI Input HI Input LO Output LO Output LO Output LO Output LO Input LO 28-pin 16-pin 16-pin 40-pin OIL OIL OIL OIL SAA7220 TDA5708 TDA8808 HEF4094 HEF4094 SAA7020 Photodiode Sig. Proc. Photodiode Sig. Proc. Expander for MAB8440 Expander for MAB8440 CIRC Error Corrector HFD UNEC UNEC EFAB EFAB EFAB EFAB FCO FCO RD SIRD FCO SAA7310 SAA7320 40-pin DIL 44-pin QFP 44-pin OFP Decoder, ERCO, CIM Digital Filter, CIM Digital Filter, CIM Decoder, ERCO, CIM Decoder, ERCO, CIM 256x0/S,Bit Strm.DAC MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE SMSE SMSE MUTE ATSB MUSB MUTE MUTE MUTE SAA7320 44-pin QFP 256x0/S,Bit Strm.DAC MUTE ATT SAA7210 SAA7220 SAA7220 SAA7310 40-pin OIL 24-pin OIL 24-pin OIL Output HI Input HI Output LO Output LO Output HI Output HI Input HI Input Input Input Input Input Input HI HI HI HI HI HI Input HI 26 26 34 5 36 36 36 4 21 6 14 4 39 11 22 23 11 18 35 36 Note: if the SAA7220 is fitted, the MUTE line on the SAA7210 and SAA7310 is usually not used. Therefore, it is preferable to use both the ATSB and MUSB lines on the SAA7220 if they are connected. All the above points normally run as +5V logic but check just in case your machine doesn't. reference of abbreviations and special circuit symbols. If in doubt, use a logic probe to help you make a decision. If your machine has a Philips chipset fitted, Table 1 gives the relevant connection points. 'Signal' is the CDEA data line name. 'Name' is the data line name most likely to appear on a circuit diagram of the device in question. 'Direction' indicates if the signal is an input or an output, and if the line is normally high ('HI') or normally low ('LO'). This applies while in the play mode with no errors for HFD and UNEC; in the play mode for MUTE (ie; not in stop, search, pause, etc); and in the stop mode for FCO (prior to the reset command being given). Be careful: not all manufacturers utilise the ICs to the fullest exte.n t so the fact that say, the SAA7210, has a input doesn't mean it is used, even though the machine may be fitted with a TDA5708 which has an HFD output signal intended for the SAA7210. Sure it sounds strange but these setups do exist so check that the inputs to each device actually do come from somewhere, and not just a termination resistor, by tracing the tracks. The servo microprocessor is normally one of the MAB84x0 or 68xx series, depending on which model player you have. The following information is only intended as a guide; your machine may be different. There are several combinations of ICs possible, depending on the model and manufacturer of the player, so determine which devices are in your machine. To configure the satellite PC board HFD to suit the polarity of the data lines from the CD player, the lOkQ linking resistors must be installed correctly. Refer to the PC board component overlay to find hole locations and designations and to Table 2 to determine the link positions. The label 'lOkQ link A-B' means install a lOkQ resistor across the holes/pads marked A and B on the overlay diagram. Leave any holes or pads not mentioned vacant. For machines using chipsets from other vendors, the relevant lines will need to be identified, then the link setup for the satellite PC board set to suit that machine's circuitry. Remember, some machines don't provide external access to the necessary information and control lines so unfortunately, there's nothing you can do. Here's an example: for a Philips NOVEMBER 1991 75 Table 2 · SIGNAL POLARITY DURING INSTALL 1OkO COMMENTS HFD HFD UNEC UNEC FC0 FC0 Norm. Norm. Norm. Norm. Norm. Norm. Play mode Play mode Play mode Play mode Stop mode Stop mode M-L and K-J M-K and L-J A-C and B-D A-Band C-D F-H and E-G F-E and H-G Pulses high on dropout Pulses low on dropout Pulses high on dropout Pulses low on dropout Goes high on start-up Goes low on start-up low high low high low high For MUTE, there are several possible combinations: (1 ). One Mute line; ie, MUTE, SMSE, etc. Wire link T-U; connect to MUTE1 input.; if Norm. low, 10kO link S-R and Q-N; if Norm. high, 10kO link S-Q and R-N. (2). Two Mute lines, same polarity; ie, ATSB and MUSB, etc. Wire link V-W, connect one line to MUTE1 and the other to MUTE2 input. If Norm. low, 10kQ link S-R and Q-N; Rx3 = 47kO; install 2 diodes, 1N914 anode to Yand cathode to X, 1N914 anode to U and cathode to T. If Norm. high, 10kn link S-Q and R-N ; Rx4 = 47kO; install 2 diodes, 1N914 anode to X and cathode to Y, 1N914 anode to T and cathode to U. (3). Two Mute lines, opposite polarity; ie, one Norm. low and one Norm. high. RX3 = RX4 = 47kO; 22kQ link T-U and X-Y; 10kO link P-R and S-Q; connect Norm. low line to MUTE2 and Norm. high line to MUTE1. Notes: Norm. low= normally low during play, goes high on Pause, Search, etc; Norm. high= normally high during play, goes low on Pause, Search, etc. CD960, the machine has a TDA5708, a SAA7210 and a SAA7220. So first find HFD. Pin 19 of TDA5708 is HFD output and pin 26 of SAA7210 is HFD input. Tracing the tracks shows that the two are connected, therefore we can tap into any convenient point between the two devices or onto the IC pins directly. This HFD is Norm. high so we fit 10k0 resistors across M-K and L-J. Now we want UNEC. Pin 36 of the <at> SAA7210 is the EFAB output and pin 4 of the SAA7220 is an EFAB input and tracing reveals they are linked. EFAB is Norm. low so UNEC Norm. low requires 10k0 linking resistors across A-C and B-D. What about FCO? The TDA5 708 has an RD output on pin 21, so we can use this. Since it is an output (ie, it generates a signal), it really doesn't matter where it goes to. So we just follow the track to a convenient point. From the chart, we need to 10k0 link F-H and E-G. That leaves MUTE. The SAA7220 has ATSB (pin 22) and MUSB (pin 23) which both trace back to the control microprocessor, therefore we use these in preference to the MUTE on the SAA7210, which in this case isn't connected anyway. ATSB and MUSB are both Norm. high so we configure the PC board for two MUTE lines, same polarity, Norm. high. This involves 10uF © C) + OPTION 1 OPTION 2 Fig.5: here's how to wire the main PC board for use with an external power supply. Option 1 is for power transformers (or plugpacks) with a single 7.5VAC winding, while option 2 is for transformers with a 12V centre-tapped winding. Make Rx2 = on if the CD player's control voltage is 5V, 390Q if the control voltage is SV, and 680Q if the control voltage is 12V. 76 SILICON CHIP 10kQ linking S-Q and R-N, fitting a 47kQ resistor for Rx4, and fitting a wire link across V0 W. Finally, we install the two 1N914 diodes; the first with anode to X and cathode to Y, and the other with anode to T and cathode to U. ATSB connects to either MUTEl or MUTE2 and MUSB connects to the other. That's all there is to it! How about a Philips CD104? This machine uses the SAA70x0 series devices, so: for HFD, we link J-L and K-M and tap onto SAA7010 pin 6; for FC0, link E-F and G-H and tap onto pin 14 of the HEF4094 adjacent to the MAB8440 microprocessor; for UNEC, link A-C and B-D and connect to SAA7000 pin 5 or SAA7020 pin 36; and for MUTE, link R-N and Q-S, wire link T-U and connect pin 39 of the SAA7020 or pin 14 of the HEF4094 (adjacent to MAB8440) to the MUTEl input. Just take your time to avoid careless mistakes. Once you have installed the required components, connect small wires from the input holes/pads and cut to length to suit the location of the tapping points. Also connect up the 6-core data cable, then mount the satellite PC board in a suitable place inside the CD player. I used self-tappers to mount the PC board on 3mm spacers attached to a nylon support bracket. Double check that the wiring of the data cable leaving the CD player is in the same order as the cable coming from the CDEA. Remember that the polarity/direction of the pins of a plug or socket change when you view it from the other side. Don't forget also to connect the satellite board to a 0V rail and to a +V supply, usually +5VDC. Now connect the satellite board to the CD player's circuitry, being very careful not to overheat the tracks or components, especially surface mount components. Once you are convinced that all is well, power up the CD player and check that it is functioning normally. If it isn't, switch off immediately and locate the cause before powering up again. Checking the analyser On the main PC board, there are two spare pads next to the transformer. These are for a link to be fitted which bridges out the optocoupler so you can power the unit up before connecting it to the CD player to verify opera- This close-up view shows the satellite board mounted inside a Philips CD104 CD player. The power supply & signal input terminals are connected to the various points inside the CD player by flying leads. tion. Make sure you use insulated wire for this link, as it is at 240VAC. Apply power, then assuming there is no smoke, check the IC sockets for correct supply voltages on the appropriate pins. If the +5V and 0V lines are OK, turn off the power, wait for the filter capacitor to discharge and then install the lCs. You can also install the LED displays and the two LEDs. There are three pairs of holes provided for the interpolation overflow LED. Use the one closest to the most significant digit. Both LEDs should stand proud of the display board such that the tip is flush with the front of the ?-segment displays. The leads on the dropout overflow LED need to be bent in a zigzag fashion to move its position in closer to the displays. Cut a piece of thick black paper to form a mask around the outside of the displays and a small hole for the LEDs to poke through. This will enhance the unit's appearance by blacking out the area around the displays. Now reapply power and the displays should all light up as zeros. If not, or if either of the overflow LEDs is flashing, shorting the two PC stakes next to the heatsink should reset the condition. Now for the moment of reckoning. If you're satisfied that everything is OK, switch the power off, remove the 240VAC link and install the MOC3041, ensuring it goes in the correct way around. Now connect the CDEA data cable to the CD player, then turn the CD player on and check that everything is functioning as normal. If so, turn the CD player off and apply power to the CDEA. Nothing should happen. If so, turn on the CD player. The CDEA's displays should light up immediately. If you have done everything properly, there should be no dramas at all. Start a disc playing, then short out the two PC stakes next to ICl (4093B). Now put the player in a search mode. If all is working properly, both displays will begin counting. Congratulations, you made it. You can now check out the truth behind those green CD pens for yourself! If there are no sparks but the CDEA doesn't seem to working, it's most likely that the links on the satellite board are not in the correct positions, or the 6-core cable has wires crossed. Either way, go back and check your work. It's all too easy to make a mistake. SC NOVEMBER 1991 77 VINTAGE RADIO By JOHN HILL A simple junkbox receiver During the early days of radio, a simple home-built 1 or 2-valve receiver was a popular choice. This concept remained current for many years and supplied hours of entertainment for radio enthusiasts in the period before television. Those early "home-brew" radios followed a fairly standard format and consisted of a regenerative circuit mounted on a baseboard with a front control panel. The circuit components could either be mounted directly onto the baseboard or on a separate circuit board. Mounted on the front panel were the receiver's controls, such as the tuning dial , reaction, on/off switch and headphone jack or terminals. Regenerative receivers were easily built and consisted of relatively few parts. But despite their lack ofrefine- ment, these little radios performed surprisingly well, although they did have certain limitations. One and 2-valve regenerative receivers could be bought in kit form or built from miscellaneous bits and pieces from one's radio parts junkbox. This latter method was almost a necessity if one wished to build a small radio receiver during the war years, when new radio components were difficult to obtain. In the early 1940s, radio magazines often featured "junkbox specials" which could use a A pair of old 30 valves were used in the receiver, together with baseboard mounting valve sockets. These valves can be replaced with earlier 4V or 6V triodes which give similar performance. 78 SILICON CHIP wide range of substitute components if the recommended types were unavailable. The war years were challenging times for the radio hobbyist. A 2-valve receiver The basic circuit for my 2-valve junkbox radio comes from a 1941 radio magazine but I have made a couple of modifications. Who blindly follows a proven circuit without making a few alterations? The additions to my version consist of: a back bias circuit to eliminate the "C".battery (I hate "C" batteries; as if" A" and "B" batteries aren't enough to contend with)! Also added was a 200 filament rheostat and a 75kQ rheostat in the plate circuit of the detector, to vary the plate voltage. The filament rheostat was necessary because a 3V filament supply was used, while the valves specified have 2V filaments . This was not an uncommon situation in the old days; the choice of filament supply being either a 2V accumulator or two 1.5V dry cells in series. There were two reasons for adding the plate rheostat. The main one was because the original circuit specified 22.5V as the detector plate supply, and this meant using a tapped "B" battery, which I wished to avoid. I hate tapped "B" batteries too! The other reason was to assist regeneration control. Although the circuit c;;alls for a lOOpF regeneration capacitor, the one actually used is less than 80pF. This restricts the range of regeneration control and this can be compensated for by using the plate rheostat. The use of a rheostat to control regeneration in this way is rather unconventional and a departure from normal procedure. However, this ad- ANTENNA 100pf .,. RFC Vl 30 200pf 200pfl 500pf .,. 75k VR2 .,. 20!1 VR1 .,. p. A- 3V A+ B+ 45V B- Fig.1: the circuit of the "Junkbox 2" receiver was taken from a 1941 publication but has been modified by the addition of a filament rheostat and a detector plate voltage rheostat. dition allows the reaction to operate smoothly over a wide range of voltages and without the need for a tapped "B" battery. It was found to work very well and is a useful control. The final modification involved the addition of a switch and a small capacitor. The switch connects (or disconnects) this capacitor in series with the tuning capacitor, thus effectively halving its capacity. This could be of benefit if the plug-in broadcast band coil is ever replaced with a set of shortwave coils, the advantage being easier tuning. However, until some more 5-pin coil formers are located, this will remain a future project. (Note: this modification is not shown on the circuit). Fortunately, my junkbox contained all the odd bits and pieces one would expect a vintage radio enthusiast's junkbox to contain and I was able to select fairly appropriate components valve sockets and a Philips audio transformer were there for the taking. The valves chosen were a pair of 2V 30s, the ones used in the original circuit. Other interesting old bits and pieces were an ancient radio frequency choke, a reaction capacitor, and some square bus bar that was salvaged from a 1920s wreck. Many early sets used square wire (bus bar) and this offers a wide contact surface when connected to the thumbscrew terminals which were used on so many early radio components. An old Emmco dial and an ancient 500pF tuning capacitor are used in the Junkbox 2. Quite a few hours were spent cleaning and restoring these components to working order. for my "war years" receiver. Items such as an old Emmco dial, black Bakelite "vintage" control knobs, metal screw top terminals, baseboard Valve specifications The valve specification manual revealed that the old 30 was no startling performer. As the valve has an amplification factor of only 9.7, it was a good thing that the proposed receiver had two of them. The 30 is a 4-pin battery triode from about the mid 1930s and was considered fairly old and obsolete way back in the 1940s. As my junkbox had half a dozen good 30s in it, it seemed appropriate to use them rather than some more modern type. Incidentally, there is an octal equivalent of the 30 in the form of the 1H4. Although both valves are electrically the same, the 30 is 4-pin based and can be used with the old style baseboard valve sockets. Scrounging around in my garage also produced suitable material for the baseboard, circuit board and front panel. Although black Bakelite would have looked nice, the circuit board and front panel were made of Masonite. Although Masonite may not be very traditional, many a homemade receiver has been constructed with this material. Layout These four front panel components were all scrounged from the author's junkbox. They are, from left: 75-ohm pot, phone jack, reaction capacitor and filament rheostat. When assembling a radio from a kit, one has instructions and a suggested layout of components to fol low. When working from a circuit only, one must think ahead and mount the parts in the appropriate places. The coil should be mounted close to the tuning capacitor and reaction control, and the wiring to these components kept as short as possible. Thought must also be given as to where the dial and other control panel items should be mounted. Both the front panel and the circuit board need to be set up with their NOVEMBER 1991 79 These circuit board components were also scrounged from the junkbox. They include the radio frequency choke, gridleak holder, screw top terminals, a capacitor and an old Philips audio transformer. the number of turns on the reaction coil. The coil specification can only be found by trial and error and my coil ended up with the following number of turns on a 1.5-inch diameter coil former: aerial coil 15 turns; tuning coil 74 turns; reaction coil 70 turns. Failure to experiment with the right number of turns for each winding can have many undesirable side effects. Too many or not enough turns on the aerial coil can make tuning either too broad or too sharp. Too many or not enough turns on the tuning coil can displace the tuning range, resulting in the set not covering the full broadcast band. And too many or not enough turns on the reaction coil can lead to uncontrollable or not enough reaction. There are many variables involved and the ultimate arrangement will differ for each set, depending on the components used. The number of turns on the reaction coil alone varies with the distance it is from the tuning coil, the diameter of the former, the gauge of wire, the capacity of the reaction capacitor, the inductance of the radio frequency choke, and the amplification factor of the valve and the plate voltage it operates at, to name just some of the factors involved. Performance Front view of finished receiver. Having the phone jack between the dial and the reaction control helps keep the headphone cord out of the way. respective components and their positions marked out in pencil. It is only when you are absolutely sure that everything is in the best possible place that the holes are drilled and various components mounted. There are plenty of options as to the layout of the parts and some thought should also be given to aesthetics as well. In other words, having the components neatly spaced and appealing to the eye is important too. Nothing looks worse than a circuit board with most of the parts all cramped up at one end. All the receiver components were mounted and wired according to the circuit diagram. Most of the connections and the back bias components (l.ZkQ and lOµF) were on the underside of the circuit board, with leads coming out through holes near the 80 SILICON CHIP front edge of the board. These leads connected to the various control panel components. The square bus bar was not easy to work with as it was very stiff and difficult to shape. As most of this wiring ended up underneath the circuit board and out of sight, it was a bit of a lost cause anyway. At this stage, everything was complete with the exception of the coil. Winding this was quite time-consuming and very tedious due to the fact . that the coil former was barely long . enough for the job. A little extra former length would have made all the difference . When winding such a coil (three separate windings on the one former), one must take into account the number of turns on the aerial coil, the number of turns on the grid or tuning coil, and It was found that the set performed quite well on 45V, even though the original circuit called for a 90V B battery. When operating on 45V, B battery consumption is approximately lmA. By using a wave trap to suppress a very close local station (3CV Central Victoria) and no earth connection to maximise selectivity, it was found that the little two-valver worked extremely well, although the reaction really needed to be kept on the boil. It pulled in several low-powered interstate stations on a 25-metre aerial in daylight hours, which seemed rather good for such a simple receiver. These stations were ZQN Deililiquin, SRM Renmark and· 7BU Burnie in Tasmania. Reception at night was even better, with a number of Queensland stations coming in loud and clear. In addition, Adelaide's SAN and Sydney's ZBL sounded like local stations. Even 2YA New Zealand came through for a short period before surging off into a prolonged fadeout. Resurrection Radio Vintage Wireless Specialists Repairs - Restoration - Sales Our skilled technicians offer QUALITY repairs and restoration . We also have a large stock of Bakelite and Timber radios fully restored and for SALE. This close-up view on the construction detail clearly shows the square bus bar that was used to make the wiring connections. All the unsightly bits and pieces are underneath the circuit board. Parts are available for the enthusiasts including over 900 valve types, high voltage capacitors, transformers, dial glasses, knobs, grille cloth etc. Circuit diagrams for most Australian makes and models. Send SAE for our :aloglie . WANTED - Valves, Radios , etc. purchased for CASH 51 Chapel Street, Windsor,Vic 3181 PO Box 1116 Telephone: (03) 529 5639 UV PROCESSING EQUIPMENT e KALEX LIGHT BOXES UV2 Exposure Area 40cm x 27cm $650.00 Rear view of the Jurtkbox 2. The coil, tuning capacitor, detector valve and reaction control are at one end of the circuit board and the audio section at the other. A neat practical layout is essential for such a project. Of course, reception conditions in central Victoria are quite different to those in metropolitan areas, where the chances of picking up distant signals between the powerful local stations are remote. One thing that did not impress was the discomfort of the old STC headphones that were being used with the receiver. It brought back childhood memories of crystal sets and the calloused ears that went with headphone listening. Those hard Bakelite earpieces become quite painful after a while! Using a pair of 8-ohm stereo headphones and an output transformer changed this situation for the better. Not only were the stereo headphones much more comfortable to wear but they also gave better sound reproduction. These improvements were made only by sacrificing a little volume, however. But despite the restrictions, there is a lot of pleasure and satisfaction to be gained from building such a basic radio. There is nothing quite like listening to the receiver that you built yourself. SC • Portuvee 4 Exposure Area 25cm x 14cm $220.00 • Portuvee 6 Exposure Area 43cm x 40cm $625.00 3M Scotchal Photosensitive Rist.on 4600 PCB Material All prices are plus sales tax if applicable KALEX I VISA 111111 40 Wallis Ave East Ivanhoe Vic. 3079 (03) 497 3422 (03) 497 3034 Fax (03) 499 2381 ELECTRONIC COMPONENTS & ACCESSORIES SPECIALIST SCHOOL SUPPLIERS NOVEMBER1991 81 DIGITAL MULTI METER HC -4510 DISPLAV:41 /2 DIGIT BASIC ACCURACY: 0.5% DC V DC VOLTAGE: 0-1000V DC CURRENT: 0-10A AC VOLTAGE: 0-750V AC CURRENT: 0-10A RESISTANCE: 0-20M OHMS CONTINUITY TES1 , DIODE TEST DATA HOLD 013030 ........... RAP $149.95 ~'<,c~':> 20 MHz DUAL TRACE OSCILLOSCOPE NOW DISPLAY: 3 1/2 DIGIT BASIC ACC4RACY: 0.5% DC DC VOLTAGE: o: 1ooov DC CURRENT: 0-10A AC VOLTAGE: 0-750V AC CURRENT: 0-10A RESISTANCE : 0-20M OHMS CONTINUITY TEST, DIODE TEST s~~~ ~\l) 013010 ........... ... ...... RRP $119.95 INIDJW$11BSIS CTR DISPLAY: . 150 mm rectangular VERTIACAL DEFLECTION: • Deflection Factor: 5mV to 20V I Div on 12 r~nges in 1-2-5 step with fine contro l , Bandwidth DC: DC to 20 MHz (-3dB) AC : 10Hz to 20 MHz (-3d8) , Operating modes CH-A, CH-B, DUAL aad ADD (ALTtCHOP L202 only) • Chop Frequency: 200 KHz Approx. , Channel separation: Better than 60dB at 1KHz TI ME BASE , Type: Automatic & normal triggered in automatic mode, sweep is obtained w.ithout input signal , Sweep Time: 0.2m Sec to 0.5 Seel Div on ranges in j..:2-5 step with fine - - - - - - , control and X-Y. 1 THIS MONTH ONLYI I • Magnifier: X5 at all times. I · I TRIGGERING : 2 FREE CRO •Sensitivitylnt:1 Divormore Ext:1Vp-pormore. 1 PROBES! I • Source: INT, CH-B, LINE or EXT . . l L_______ ____ :_ ___ J • Triggering Level: Pos1t1ve and Negettve, contmuous1y variao1e 1eve1; Pull for Auto. • Sync: AC, HF Rej, TV (each + or- ) at TV Sync. TV-H (line) and (frame) sync are switched automatically by SWEEP TIME!Div switch. HORIZONTAL DEFLECTION • Def lection factor: 5mV to 20V/ Div on 12 ranges in 1-2-5 step with fine control • Frequency response: DC to MHz (·3dB) • Max Input Voltage: 300V DC + AC Peak of 600V p-p , X-Y operation: X-Y mode is selected by SWEEP TIME/ Div switch. • Intensity Modulation Z Axis: TTL Level (3Vp•p- 50V) +bright, · dark OTHER SPECS:. Weight: 7Kg Approx • Dimensions: 162 (H) x 294(W) x 352(D)mm. IDIISIPILAY: 3 1/Q IDIIGIIT DC VOLTAGE: 0-1000V DC CURRENT: 0-10A AC VOLTAGE: 0-750V RESISTANCE: 0-20M OHMS CONTINUITY TEST, DIODE TEST, DATA HOLD , TR HFE GAIN, AUTO RANGE DMM WITH BAR GRAPH 013040 ................. .. .. RRP $99.95 NOW $89.95 012105.......................... RRP $750 NOW $695 DIGITAL MULTI METER HC-3500T DISPLAY:3/12 DIGIT BASIC ACCIJRACY: 0.So/AD DC DC VOLTAGE: 0-1000V DC CURRENT: 0·20A AC VOLTAGE0-750V AC CURRENT 0-20A RESISTANCE : 0-20M OHMS TEMPERATURE:-20C -1200C CONTINUITY TEST, DIODE TEST TEMPERATURE CAPACITANCE FREQUENCY, hie TEST, DATA HOLD. 013000 ... ................ RRP $169.95 lflliffll $114'9..!15 ANALOGUE/DIGITAL MULTIMETER HC-5050DB 3 1/2 DIGIT BASIC ACCURACY: 0.5% DC DC VOLTAGE: 0·1000V DC CURRENT: 0-10A AC VOLTAGE: 0•750V AC CURRENT: 0-10A RESISTANCE: 0-20M OHMS DC AC RMS:•45dB -+50dB TEMPERATURE: ·20C-1200C AC FREQ SPREAD: 50Hz-2KHz CONTINUITY TEST, .DIODE TEST 013020 ........ .......... RRP $169.95 lfD&' $11419..95 LOGIC PROBE (LP-2800) USEFUL FOR TTL AND CMOS. HIGH & LOW INDICATORS PULSE MEMORY. FOR THE HOBBIEST OR SERIOUS TECHNIICIAN FOR TRACING THOSE HARD TO FIND FAULTS ON LOGIC BOARDS. O11272 ...................... .... .. RRP$29.95 NOW $19.95 100 MHz 3 CHANNEL 8 TRACE MODEL 5510 This instrument meets the customers needs •in quality of performance, efficiency, function , design, and cost! Being rugged, highly reliable and a multi•purpose 3 · ch annel, 8 trace oscilloscope with a 6 inch domed mesh type 14kV post deflection acceleration cathode-ray tube and with a fine red internal graticule. FEATURES: • Compactness, lightweight, ruggedness and simple design . • The diecast frame provides compactness lightweight and ruggedness . • Easy Operation Light torque lever switches and push button switches are used . • High Brightness CTR, high acceleration voltage and high beam efficiency of the 150mm rectangular CTR ensures a bright high speedsweep observation • Multi mode display system CH1 , CH2, CH3, Add any combination or all the channels may be viewed simultan iously. Maximum 8 trace displaying is possible with the ALT sweep function. • High sensitivity and wide frequency bandwidth . The maximum vertical sensitivity is 1 mVIDIV (when x 5 MAG)at 20 MHz or greater 3dB and mVIDIV at 100 MHz or greater •3dB. • High input impendance The input impendance of CH1, CH2, CH3, is 1Mnt2%, 25pFt3pF Q12109 ...... ... RRP $2995.00 NOW $1,995 SCHOOLS & COLLEGES TAKE NOTE! ONLY $1,695 tax exempt. 141D ........ $1.Q5 141E ....... ..$2.95 142E or Teccor 008L Trlac .$ 2.25 1460 ........ $2.8S 1510 .... .... $2.QS 038 or R 100·6 ... ..$0.90 060 Equiv. Tag 403DE ...... $1.50 22D .. .... $2.50 22E ........ .. $1.95 ........ $1.Q5 ....... . $1 .20 ........$ .......... $1,00 ...... $0.QO ........ $1.00 .. $1 .Q5 ... $1.10 .. $1.QO ........ $2.00 .. $0.35 ..... $0.30 ........ $0.30 ....... . $0.30 .... .... $0.30 ........ $0.30 .... $0.30 ........ $0.30 ........ $0.30 ···· •· $0.30 ........ $6.96 ....... $5.70 ........ $7 .95 ....... $1 .50 ........ $2 .Q5 •. . $1 .00 .... $1 .00 ....... . $2.20 ....... $0.40 ........ $0.50 ······ $1.50 ····· $1.50 .. $0.30 ........ $3.90 ········ $1 .50 ····•··· $1 .00 ········ $1.00 ....... $0.35 ........ $0.90 .... $1.00 ... $1.15 ········ $1 .30 ....... $1 .20 . . .. $1 .90 ........$6.95 ...... ... $9.Q5 .... $14 .50 ..... $9.95 .... $14 .50 BC54L ........$0.15 BC550 ........... $0.30 BC556 ........... $0.30 BC557 ........... $0.15 RC558 ........... $0.15 BCSSQ ........... $0.15 BC63Q ........... $0.80 BC640........... $0.80 BD13L ........ $0.90 B0140 ........... $0.90 B0237 .. ... .... $0 .90 B0238 ........... $0.90 B0650 ........... $1.95 9064Q... ..... $1.65 90647 ........... $1.80 90681 ........... $2.00 90682 ....... .... $2.00 9F115 .. ..$1.00 9F180 ...... .....$1.20 BF199 ........... $0.60 BF245A ......... $1.Q5 BF469 .......... $1.20 BF470 .......... $1.20 BFY50.. ... $1.50 BFY90 ........... $3.00 BU208A ........ $4 .90 9U326A ........ $4.Q5 BUXBO .......... $5.9ll 9 U806 ........... $7. 95 MFE131 ...•....$2.90 MFE3001 ......SQ.90 MJ10012 .. ..... $5 .Q5 MJ802 ........... $7.80 MJ15003 .......SQ.50 MJ15004 .......$9.70 MJ15024 ...... SQ.60 MJ2955 .... $2.95 MJ4502 .... .... $8.50 MJE340 .... ....$2.00 MJE350 ........ $2.50 MJE2955 .. .. ..$4 .90 MJE3055 ...... $3.90 MJE13007 .... $4.95 MJE13009 .... $9.95 MPF131 ........ $2.90 MPSA06 ........$1.00 MPSA13 ........ $0.50 MPSA42.. ..$0.80 MPSA43 ........ $0.50 MPSA93 ..... ...$0.50 MPF102 ........ $0.90 MPF109 .. $0.90 MPSU56 ........$1 .75 PNl00 ....... ... .$0.25 PN200 .......... . $0.25 TIP31 B .... .. ... $1 .00 TIP31C ..... ....$1.20 TIP32B .. ... $1.00 TIP32C .......... $1.20 TIP41A. ..$1.QO TIP41C .......... $2.00 TIP42A... ..$1.90 TIP42C . . .. .$2.00 TIP49 ....... .....$1 .90 TIP50 ............ $2.20 TIP53 ... ... ... ...$2 .!50 TIP112 ..... .. ...$2.50 TIP116 .. ........ $2.50 TIP117 ..........$2.50 TIP120 . ....... $2.90 TIP122 ......... $1.Q5 TIP125 ..... ....$2.90 TIP127 ...... ...$1.95 TIP147 .. .. ..... $4 .95 TIP2955 ..$2.25 TIP3055 .... .... $1 .95 t·lltltl ..l.AMf. ........... . $3.50 .Descripti on . 1 N4002 200V .$0.10 1 N4004 400V .$0.10 1 N40071CXX>V .$0.20 UMf. .. $6.50 Description .. 1NS401 50V ..$0.40 1 N5404 400V$0.40 1 N54081 OOOV$0 .65 GERMANIUM DIODE ......... $6.50 ........ $6.75 ...... $8.40 t!iPirir1fN1 AC 128 ... ........ $2.95 BC107 ...... ..$0.80 ec108 ........... so .80 BC109 .......... .$0.80 .......... $0.30 .......... $0.30 .......... $0.30 ··········$0.30 ...$0.40 ......$0.40 .......... ,0.30 . ......$0.15 ....$0 .15 Description .. ...... $ OA47 OA90 OA91. OA95 . ..$1 .50 .$0.75 ..$0.75 ..$0.75 lii!JI 1 N746A 3V3 .$0.25 1N747A 3V6 .$0.25 1 N748A 3V9 .$0.25 1N749A 4V3 .$0.25 1N750A 4V7 .$0.25 1N751A 5V1 .$0.25 1N752A 5V6 .$0.25 1 N753A 6V2 .$0.25 1N754A 6V8 .$0.25 1 N755A 7V5 .$0.25 1 N756A 8V2 .$0.25 1N757A OV1 .$0.25 1 N758A 10V .$0 .25 1N962A 1N75QA 1Nll64A 1N965B 1N966B 1N067B 1N9689 1N969B 1NQ70B 1NQ71B 1N9729 INll73B 1N974B 11V.. $0.25 12V ..$0.25 13V .. $0.25 15V.. $0.25 16V .$0.25 18V .$0.25 20V .$0.25 22V .$0.25 24V .$0.25 27V .$0.25 30V .$0.25 33V .$0.25 36V $0.25 1W ZENER DIODE Description ........$ 1N4728 3V3 ..$0.35 1N4729 3V6 .. $0.35 1N4730 3V9 ..$0.35 1N4731 4V3 ..$0.36 1N4732 4V7 ..$0.35 1N4733 5V1 ..$0.35 1N4734 5V6 .. $0.35 1N4735 6V2 ..$0.35 1N4736 6V8 .. $0.35 1N4737 7V5 .. $0.35 1N4738 8V2 .. $0.35 1N47311 QV1 .. $0.35 1N4740 10V .. $0.35 1N4741 11V ..$0.35 1N4742 12V .. $0.35 1N473313V .. $0.35 1N474415V ..$0.35 1N4745A 16V$0.35 1N4746 18V .. $0.35 1N4747 20V ..$0.35 1N4748 22V .. $0.35 1N4749 24V ..$0.35 1N4750 27V ..$0.35 1N4751 30V ..$0.35 1N4752 33V .. $0.35 1N4753 36V .. $0.35 1N4761 75V .. $0.80 1 l i&i1I SW ZENER DIODE De scription ... ... ... $ 1N5339 B 5V6$1.50 1N5342B 6V8$1.50 1NS349B 12V$1.50 1N53S8 1SV$1.SO 1NS361 27V $1 .S0 1N63SQ 24V $1.50 1N5363 30V $1.50 1N5372 62V $1.50 ••U1-i0!--W Description .. ..... $ 1MHz .... $6 .00 1.8432MHz ... .$7 .50 2MHz ... ......... $3.00 2.4576 MHz .. .$2.00 3MHz .............$4.90 3.57954MHz .. $3.00 4.00 MHz ....... $3.00 4.19430MHz .. $3.00 4.433618MHZ$2.00 4.44 MHz ...,... $2.00 4.9562 MHz ... $3 .00 5MHz ...... ....... $2.00 6 MHz ... ..$2.00 6. 144 MHz..... $3.00 8.00 MHz ... .... $3.00 8.86723MHz .. $3.00 10 MHz ... ....... $2.00 11 MHz ......... $3.00 12.00 MHz .... $3.00 14.318 MHz .. $2.00 15 MHz ......... $2.00 16.00 MHz .... $3.00 20.00 MHz ... .$2.00 24 MHz ........ $3 .00 48MHz ...... .. .$2.00 32.768KHz .... $2.00 ■rD=NU◄ Desc ription ... ...... ..$ 74HCOO ... $0.75 74HC02 ......... $0.75 74HC04 ......... $0.75 74HC08 ......... $0.75 74HC10 ......... $0.75 74HC11 ..... .... $0.75 74HC14 .........$1 .60 74HC30 ......... $0.60 74HC32 .........$0.80 74HC42 ......... $0.90 74HC74 ......... $1.10 74HC85 ......... $1.40 74HC86 ......... $1.10 74HC123 ......$1.40 74HC132 .......$1.25 74HC138 ....... $1.40 74HC157 ....... $1 .25 74HC181 .......$2.2S 74HC184 ..... ..$2.25 74HC174 ....... $1.40 74HC244 .......$2.00 74HC245 ....... $2.50 74HC273 ....... $2.75 74HC367 ....... $1.85 74HC373 ....... $1.80 74HC393 ....... $2. 75 74HC4040 ..... $1.85 74HC4060 ..... $3.95 74HC4068 ..... $1.70 tnil't1\'l'l'f Descnpt10,:i .. . ..... $ 74S04............$1.20 74S08 ............$1 .50 74S30............$1.00 74S32......... ...$1 .00 74S132 ....... ... $3.50 74S133 ..........$1.20 74S136 ..........$2.SO 74S139 .......... $3.30 74S174 .......... $3.50 Description .. ...... $ 4000 .............. $0.75 4001 •·•·•• ····• ·••$0.45 4002 ...... $0.55 4006 .. . ·······'1.55 4007 ...... $0.45 4008 .............. $1.70 400Q .............. $0.90 4010 ...... ........ $0.90 4011 .............. $0.45 4012 .............. $0.45 4 013 .............. $0.70 4014 .... . ..... $1.00 4015 ......... ..... $0.90 4018.. ... $0.70 4017 ........... ... $1 .35 4018 ···••······ ···$0.50 401Q ... $0.80 4020 ......... .....$1.40 4021 ......... .....$1 .50 4022 .............. $1.45 4023 ............. $0.45 4024 ............. $1.60 4025 ............. $0.45 4026 .. ... $1.10 4027 ·· ········ ···$0.85 4028 ............. $1.15 4029 .. $1.50 4030 .. . ... $0.50 4033 .. .. ... $2. 75 4038 . . ... $2.25 4040 .......$1.20 4042 ..... ........ $1.50 4043 ......... $1.20 4044 ........$1.25 4045 ............. $4.90 4046 .......... ... $1.00 4047 ..... .......$1.90 4049 .. ...$0.60 4050 ............ $0.60 4051 ..............$1 .20 4052 ··• .. .. ..... $1.20 4053 ............. $1.20 4060 .. ........... $2.50 4066 .......... ... $0.80 4068 ...... $0.50 4069 .. ... ........ $0.50 4070 ............. $0.50 4071 ....... ... $0.50 4073 ........ ..... $0.50 4075 ..... $0.50 4076 ..... ...... $1 .90 40n .. ...... .. ...$0.50 4076 .......$0.50 4081 .. ·······$0.50 4082 ............. $0.50 4093 ···•···· ..... $0.80 4098 ........ $1.90 45104 ....... $7.25 4503 .. ........... $1.30 4510 .. ...... ..... $1.40 4511 .. ...... ..... $1 .45 4512 . ............$1.40 4514 ... ········· ·$2.60 4515 .............$1 .90 4516 ..... ... ..... $1.60 4518 .. ........... $1 .50 4520 . ............ $1.00 4522 .. . .. .....$1.90 4526 .. . ... $1.00 4528 .. ..... ...s1.g5 4532 ... . ..... $2.65 4536 ... ····· ·····$6.50 4538 .............$1 .20 4543 .............$2.50 4556 .. .......... $1.25 4584 ..... ..... ...$1.00 40014 ··········· $'-50 40175 ..........$2.00 14\ili De sc ription ....... $ 74COO ... ..... ... $1.00 74C04 ..... $1.00 74C08 ........... $1 .00 74C14 ........... $1.75 74C74 .......... $1.00 74C86 ..........$1.50 74C90 ...........$2.50 74C192 ... .....$3.50 74C221 . ..... .. $3.95 74C244 ........ $3.Q5 74C373 .. ...... $6.95 74C908 ........ $2.110 74C922 .......$14.95 74C926 ...... .$13.95 74C948 ..... ..$24 .50 Description ... ....... $ 74F00 ............$0.25 74F04 .. .........$0.25 74F32 .$0.25 74F74 ..$0.25 74F10Q ..........$0.50 74F138 ... $1.00 74F151 .......... $1.20 74F153 .......... $1.20 74F157 .......... $1 .20 74F194 ... $2.41 74F244 .... $3."1'; Oescnpt,on .... ....$ 74LSOO ... ...... $0.30 74LS01 ...... ... $0.60 74LS02 ......... $0.60 74LS03 ......... $0.60 74LS04 ... ......$0.75 74LS06 .........$0.75 74LS08 .. $0.60 74LS10 ......... $0.30 74LS11 ..$0.75 74LS13 ...... ... $0.90 74LS14 .........$0.7S 74LS15 ......... $0.80 74LS20 .... ..... $0.90 74LS21 ........ .$0.90 74LS27 ...... ... $0.90 74LS30 ......... $0.30 74LS32 .. $0.60 74LS379 ....... $0.70 74LS38 ... ...... $0.80 74LS42 ......... $1 .20 74LS47 ......... $ 1.80 74LS48 .........$1 .80 74LS74 ......... $0.40 74LS75 ......... $1 .20 74LS76 ... $1.00 74LS85 ......... $0.85 74LS86 ......... $0.60 74LS90 ..... $1 .20 74LS92 ......... $1.20 74LS93 ......... $1.50 74LS95 ..$1 .20 74LS107 .... .. .$0.90 74LS109 .. .....$0.90 74LS112 ........$0.70 74LS123 .......$ 1.30 74LS125 .... ... $ 1.00 74LS126 .... ... $1.00 74LS132 .......$1 .00 74LS136 ....... $0.80 74LS139 ....... $0.80 74LS145 ... ... $1 .50 74LS147 ...... $2.50 74LS151 .... .. $1.20 74LS153 .. ... $1.00 74LS155 .......$0.50 74LS156 .......$1 .50 74LS157 .. $1 .20 74LS158 ......$1 .00 74LS160 .......$1 .50 74LS161 .... ... $1 .00 74LS162 .......$0.50 74LS163 ...... $1.10 74LS164 .. ....$1 .40 74LS165 ...... $1.20 74LS166 ....... $1.25 74LS168 . .....$2.10 74LS174 .$1.20 74LS175 ...... $0.70 74LS181 ..... ..$4 .00 74LS1111 .. $1.20 74LS193 ......$1 .20 74LS1Q5 .. ...$0.50 74LS196 ....... $1 .20 74LS221 ... ....$2.00 74LS240 .......$1.40 74LS241 .. ... ..$0.95 74LS243 ....... $1.10 74LS244 .... ... $2.20 74LS245 ...... .$2.95 74LS257 .... ... $1 .20 74LS258 ...... $1 .20 74LS2511 ....... $2.25 74LS266 ....... $0. 70 74LS273 ......$ 1.00 74LS323 .......$6.50 74LS352 74LS365 74LS386 74LS387 74LS373 74LS374 74LS375 .... ... $2.20 ... ... . $1 .00 ... ... $1.00 ... .. .. $ 1.00 .. ... .$2.00 .... ... $.2.00 ....... $1 .00 escnptlon ... 7400 ..............$0.80 7402 ..............$1.00 7403 ..............$1.00 7404 ............. .$0.30 7406 .............. $0.40 7407 ..... ......... $0.50 7408 .............. $1 .00 7409 ...... $1.00 7410 . .... $1 .20 7414 ..............$1.50 7416 ..... ········'0.50 7430 .. ............$1.00 7432 .. ...... ......$1 .00 7438 ....... $0.80 7442 .............. $1.50 7445.. . ......$1.00 7446 ............. $1.20 7447 ..... $1.75 7473 .............. $1.20 7474 .............. $0.40 7475 .............. $1.20 7476 .............. $1.50 7483 .. ........... .$1.10 7490 ..$1 .20 7493 ..... ······ ·'1 .25 74121 ....... .... $1 .55 74123 ..... ..$0.50 74125 ........... $1.00 74126 ........... $1.00 74150 ........... $1.90 74154 ....... $2.50 74157 .......$1.30 74161 ........... .$1 .20 74164 .. .........$1 .20 74177 ....... .... $1 .Q5 74193 ···········'1 .50 741Q5 .. .$1 .00 74197. ...$1.20 74283 .......... .$2.45 74290 .. $0.90 !ftl'Kf·TI•f Description .......... $ 0AC0800 .. $4.95 DAC0808 .. ...... $4 .90 ADC0800CN .. $29.95 AOC0803 ...... $13 .50 ADC0804 ....... .. $7.95 AOC0808 ....... $13.00 AOC0820LCN.$27.95 DAC0832 ......... $7 .95 DAC1020 ....... $16.28 11C90 ............ $16.50 DAC1220 ....... $22 .95 DAC1408 .........$1.00 .AD590J ......... $12.95 .LM393 .............. $0.60 .LM394CH ....... $7.Q5 .LM395T.. ......... $9.95 Description ........ .. $ LM395K .......... $7.95 2114 .... ........ .... $5.20 LM396K ........ $16.50 2716 .............. $12.50 .. LM399H .. ........ $7.50 2732-200 ........ $8.25 LM711 .... $1.20 2764-250...... . $8.95 LM725......... ... $7.50 27128 .............. $8.00 LM733 ............ $1.50 27256 -250 ....... SQ.SO LM741 ............ $0.60 27512-250 .....$14.95 LM747 ............ $1.50 27-lMEG .......$29.50 LM748 ........... $1.10 27C64-200NS. $8.95 LM759 ............. $3.90 27C128 ......... $12.50 LM833 ........... $2.10 27C256/ LM1830 ......... $4.90 250NS .......... $15.50 27C512 ........ $22.50 27C 1 MEG ... $34.50 LM1886 .......... .$9.10 4116 16K ....... $3.95 LM2907·14 ..... $3.50 4164-10 ......... $4.95 LM2907·8 ....... $5.10 4464·10 ......... $5.50 LM2917-14 ..... $2.50 4464-08 ... .. ..... $5.90 LM2917·8....... $4.80 41256-10 ... ... .. $4.95 LM3900 .......... $0.80. 41256-08 ..:: ... $5.50 LM3909 .......... $2.50 44256·10 ...... $13.95 LM3911 .. $3.95 44256-08 •·• ···$9.00 LM3914 ......... $2.90 44256-07 ...... $15.95 .LM3915 .. ......... $2.90 6116 . $5.50 .LM3999Z ....... $5.95 6264LP·10 .. $111.95 .LM 4250 .. ....... $2.45. 62256LP-10 . $39.95 .LM 11CN ..... .... $4.95 1M•10........... $9.00 LM13600 .... $2.70 ···$9.00 LMC555 .. ... ... .. $1 .25 lM-08 ~~::~~~::::::: :~:~ MAX232/ICC232 HMC232 ........ $11.95 OM350 .......... $21.00 MC1408L8 ...... $7.50 MC1458 .......... $1.20 MC1488 .......... $0.60 MC1489 .......... $0.60 MC1496 ......... . $2.50 MC3334P........ $6.95 MC340 1ilP... ... $8.95 MOC3021 ........$1 .95 - D escription . $ 256 X 9-80 . .$24.00 1M x 9-llO ... $89.00 1M X Q-70 ... $99.00 ..$1.50 1 NE555 ..... ..... ... $0 .50 NE556 ..... .... .. $0.95 NE558 . $6.50 .N E564 ............. $7 .00 NE566 ............. $2.90 NE567 ........... $2.00 NE570 ... $8.95 NE571 .. $6.95 NE572 ......... . $11 .20 .INS8250N .... $18.10 .TA7205P......... $2.95 TOA 1024 ........ $3.90 TEA1002 ....... $17.50 TL064 ............. $2. 10 TL071/ LF351. $1.20 TL072/ LF353.$1.60 TL074/ LF347.$1.40 TL081 ... .$1.90 TL082 $2.20 TL084 ............ $1.50 UA710CN ... ... $1.00 .UA73Q .. .......... $2.75 .UPD8288 .... $16.50 XR2206 .. ........ $9.95 Description .. .. ....$ 256K x 9-80 $24.00 1M X 9-llO .... $89.00 1M X Q•70 .... $99.00 111<at>1!-1 Description ....... $ 76489 ........ ... $12.50 ICL 7660 ... ...... $6.90 VN88AF. .........$5.95 MM536L ... .. $4.g5 Desc npt1on 6502A ..... ...... $16.96 6522A .. ......... $15.95 6802... $7.00 6809 .......... ... $17.00 6821 ............... $5.50 6845 ....... $9.95 6850 ........ ....... $3.50 7910. $29.95 8035N·6 ..... .... $6.90 8039 .... $9.90 8080 ......... $8.00 808 5A . ... $16.50 8088 ············ $12.50 ICL7106 ....... $15.95 . Descri ption .. $ AY·3· 1015 .... $11 .95 . XR2209 .. ... ..... $6.Q0 ICM7216B .... $59.50 LF13741 ...... .. $0.80 XR2211 . ........ $7.95 .AY-3-8910 .... $19.95 .AY-5-8116 .... $14.50 XR2216 .......... $5.90 NS16450 ..... $26.95 S3530 .......... $24.95 CA3028 ......... $3.95 XR2240 .......... $6.95 CA3086 .. ....... $1.20 XR2243 .. .. ...... $5.95 SP0256 .... .. $21.95 TR1883 .......... $8.90 CA3130E ....... $2.90 26LS30 ........ . $2.00. CA3130T... .... . $3.95 26LS31 .......... $2.00 V20A ....... .... $35.95 CA3140E ........ $1 .30 26LS32 ... ....... $2.00 V20 ............. $29.95 CA3140T... .... $2 .95 5534AN ..........$3.QS WD2123 ..... .. $29.QS CTS256A ..... $45.50 . 8155 .... ........... $8.95 XR8038 .......... $7.50 ...$8.50 Z80A CTC ..... $8 .50 OM2502 .... ... $13.60 8156 LF347 ............ $1.40 81 LS95 .. ... .$1.00 Z80B CPU ... s13.50 LF351 N ....... ... $1.20 81LS96 .......... $2.75 Z80A CPU ... ... $5.75 $3.00 ZBOA PIO . .... .. $4.50 LF353 ....... ..... $1.60 8216 ........ $14.60 Z80A SIO .... $14.50 LF356N .......... $1.50 8237 8255 ............... $6.90 LF357 ........... $2.95 LF398 ........... $5.90 8279 .............. $8.50 LM301 H ........ $1 .50 8830 .............. $6.95 LM301 N ......... $0.50 95H90 .......... $10.50 LM302H ....... . $6 .50 9667 ........... ... $0.90 LM305H ... ...... $1.50 . Q668 .. ·····•·· ··· $2.95 LM307CN ...... $1 .50 LM308 ........... $0.50 LM309K ........ $2 .85 LM310N ......... $4.95 . LM311 .......... $1.00 . LM324.. ...... $1.20 LM331 ............ $6.00. LM339........... $0.60 . LM348 .... $1.00 LM34L .... .... $2.95 LM358 .... ...... .. $1 .40 LM361 ... ....... .. $4 .Q5 LM380N-14 .... $US LM380N-8 ...... $1 .50 LM381 .... .. .... .. $4.QS LM382 ............ $3.50 LM383 ............ $4.95 LM384..... ..$3.50 LM388·1 ......... $1.40 LM387 ....... $2.75 LM390 ....... .... $2 .QS LM3Q2 . Description LM317T...... . LM317KC .... . LM320K12 LM320K-05 LM320T-5 ..... LM323K. LM326 .... LM329DZ .. LM334Z ........ $1.70 LM335Z .......... $2 .50 LM336Z •2.5V.. $2.95 LM336Z5 .0V... $2.95 LM337T. ... ...... $2.90 LM337KC ..... $12.50 LM338K $9.45 LM340T•5.. $0.90 LM340KC -5.....$2.95 LM340T-5 ...... $0.90 LM340KC•5.... $2.95 LM340T-12 ..... $0.90 LM340T·18 ... . $2.00 LM340T-15 ..... $0.00 LM340KC-12 .. $4 .95 LM3SOT. ......... $8.40 LM350K ...... .. $11 .50 LM378 ............ $6.95 TL494 .......... .. $4.90 LM723CH ...... $1 .50 LM723CN ..... .. $0.95 78HGK .. ...... .... $9 .50 78P05GC .... $14.50 7805 ................ $0.75 78L 12 ... ... ........$0.75 78L 15 ... ... ..... ... $0.75 79L05.... . $1.20 79L 12 .. ........... $1 .20 79L 15 ........... .. $1 .20 LM 396K ......... $16.50 Description . ... ...... $ 3 mm LEDS Rod $0.20 Green ....... ... .. $0.30 Yellow .. .. ..... ... $0.30 Orange .... ..... $0.30 5mm LEOS Red ................. $0.20 Green .... ........ $0.30 ve·llow ......... ... $0.30 Orange .......... $0.30 10mm JUMBO LEADS Rod ........ ......... $1 .50 Gr11n ... . ........ $1.50 Orange ..... ... . $1.50 SUPER BRIGHT LEDS Rod .. .......... .... $1.00 Green . ........... St.00 Yellow .. ........ .. $1 .00 5mm FLASHING LEDS Rod ............. .... $1 .25 RECTANGLE LEDS Rod ........ ...... $0.25 Green . .......... $0.30 Yellow .... ....... $0 .30 Orange .......... $0.30 5mm RED/GREEN DUAL LEO ..... $1.05 f"-Prices-arei-9.- 7 l 10-99 : : : : less 1cv.. 100+ less 20%. : : : L.----------.J I PRODUCT SHOWCASE Large screen TV from Sanyo This 78cm large-screen TV from Sanyo has an inbuilt teletext decoder, a stereo tuner and fully automatic tuning that can memorise all TV stations, as well as three VCR positions. Other features include: a combined VCR/TV remote control; last-status memory function; an on-screen function display; a sleep timer; and auto shut-off. If any feature or function is forgotten , it can give an on-screen demonstration to remind you. Recommended price is $3499 and it is available from selected retailers. For more information, contact Sanyo Australia on (02) 763 3822. I large handwound units which are cooled by two thermostatically controlled fans. Other nice features are quality meters, an inbuilt oscillator, inbuilt stereo speakers, and oscilloscope and frequency counter outputs. The price is $1495, including sales tax. For further information, contact Kingsley Instruments, 17 Blackburn Drive, Cheltenham, Vic. Phone (03) 583 4020. I Universal remote control for TVs & VCRs Audio interface for testing & repair For years, audio service technicians have had to endure an untidy mass of cables and connections to test audio equipment. The Audio Interface solves all that. This precision-made instrument enables you to link all the audio test gear on your service bench to one control panel, thereby eliminating the usual mess of connections that testing audio gear involves. You can test virtually any audio source, from a Walkman tape player to CD players and large stereo receivers. You can do gain and power measurements up to 800 watts on stereo gear. The inbuilt dummy loads are Sensitive FM wireless microphone This stylish wireless micro phone from Arista has a range of 100 metres and has high/low switchable sensitivity. The audio frequency response of the microphone is 50Hz to 15kHz and the unit can be tuned from 92-104MHz for reception on any FM radio. An electret condenser type microphone is coupled with a FET preamp to provide high sensitivity. The unit is powered by a 9V battery and is available for $24.95 84 SILICON CHIP from Rod Irving Electronics, 74 Parramatta Rd, Stanmore, NSW, or from their Melbourne stores. Losing the remote control for the TV, or trying to turn off the video with the CD remote can be a real bind. This universal remote control can replace the infrared remote controls of up to five audio/video components by learning and then mimicking their command codes. The unit has 8Kb of memory which enables it to store up to 85 individual codes. An LCD screen on the unit shows the device being accessed, as well as the time of day. Included is an alarm and a timer (for those who fall asleep in front of the TV)! A perspex stand with a list of the 85 memories is included so that you don't have to continually guess what codes you have stored. The universal remote control sells for $74.95 and comes from Rod Irving Electronics, 74 Parramatta Rd, Stanmore NSW, or from their Melbourne stores. 60 watt flush-mount loudspeaker system Now your music can be heard and not seen with a pair of these 2-way flush mounting speaker systems from Altronics. Rated at 60 watts, they feature a 165mm 5-).Jlch polycarbonate woofer and a 25mm soft dome tweeter, both with high-temperature voice coils. These speakers can be installed in either new or existing walls or ceilings and are supplied in a white finish. They can be painted to blend in with any decor. They are also weather resistant and may be installed outdoors. For large public address installations, they can be fitted with 100 volt line transformers. At $125 each or $225 a pair, they are ideal where speakers need to be out of sight. For further information, contact Altronics Distributors, 17 4 Roe St, Perth 6000. Phone (09) 328 2199 . NewSPDT GaAs switches George Brown now has in stock a series of broadband (DC to 4.6GHz) double-throw monolithic switches from Avantek. The MGS-70018 and MGS-71018 are both available in 8-lead surface mount packages and are actuated by a -5V control voltage. The difference between the two is that the 70018 version terminates "off" signals to ground while the 71018 terminates them to a 500 load. The current drawn for the "on" port is less than lO0µA. Both are designed for fast switching applications where low insertion loss and high isolation are important. Some of the varied applications include instrumentation, communications, radar and ECM circuits. For more information, contact George Brown & Co Pty Ltd, Unit 1, 38 South St, Rydalmere , NSW 2116. Phone (02) .638 1888. Hand-held LAN cable testers Hewlett-Packard has recently released a series of hand-held local area network (LAN) cable testers designed for network-servicing companies who install and maintain LANs. Called time-domain reflectometers (TDRs), they are scanners capable of quickly isolating faults in most LAN cabling systems including Ethernet and Arcnet networks. There are three models: the HP J2181A cable scanner, the HP J2177A pair scanner and the HP J2187 A quick scanner. The cable scanner locates faults in twisted-pair or coaxial LAN cabling and it can also monitor LAN traffic and graphically display and print out a 24-hour activity log. The pair scanner is suited to more complicated twisted-pair networks, including all the features of the cable scanner as well as network-testing and monitoring functions. The quick scanner troubleshoots networks and performs standard LAN diagnostic tests. For further information, contact Test and Measurement, HewlettPackard Australia Limited, 31-41 Joseph St, Blackburn, Vic 3130. Phone (03) 895 2869. Humidity sensor for elevated temperatures Novatech Controls has developed a humidity transmitter capable of operating at up to 600°C. The zirconia sensor, developed by the CSIRO , is capable of working in steam, fuel-fired and other heated environments. The new transmitter allows fine regulation of the water vapour content in a dryer or flue gas atmosphere, thus saving energy and attaining a higher level of quality control. For further details, contact Novatech Controls, 429 Graham St, Port Melbourne, Vic. Phone (03) 645 2377 or (008) 33 7063. Fax (03) 646 3027. Production aids for PC boards Scope has just released a squeeze-type flux dispenser and a brush-type solvent applicator. The 60ml flux dispenser comes with three capillary tubes to meter fluxes of different viscosities. A nylon-bristle brush is fitted to the 60ml solvent dispenser. Finger pressure controls the solvent flow rate through the brush. For more information, con- tact Scope Laboratories, 3 Walton St, Airport West, 3042. Phone (03) 338 1566. NOVEMBER 1991 · 85 The Story of Electrical Energy, Pt.15 While there is now considerable interest in battery powered cars, electric and dieselelectric heavy-haul rubber tyred vehicles have been in use for some time and they are huge. Imagine avehicle weighing 85 tonnes and powered by half a megawatt of electricity! By BRYAN MAHER The mining industry is a source of inspiration for electric and mechanical engineers alike. All modern mining concerns think big; big machines, big problems, big costs! This month, we take a look at three vehicles designed for very specific applications in underground and open cut mines. Each uses electrical and mechanical engineering in unique ways to increase material throughput at less cost. Deep underground hard rock mines, such as Mount Isa in western Queensland and Kristine berg in Sweden, produce vast quantities of valuable metals: copper, silver, nickel, lead and so on. The ore must be won, transported and crushed before smelting can extract the pure metal. Such mines invest colossal sums in vertical lift shafts more than 1000 metres deep, together with the cages and hoist equipment. At many levels, networks of horizontal tunnels, up to 6km long, criss-cross the ore body as the miners dig into the rock. Lifts versus ramps Sometimes, it is necessary to work a new ore body below areas presently accessed by lift hoist. For example, the Mount Isa 3000 ore body lies below the existing R62 and U62 vertical shaft systems. In such cases, engineers must assess the comparative costs and viabilities of either deepening the ·lift system or accessing the new ore by ramps from old areas. Where ramps are chosen, large rubber tyred vehicles are used to haul the ore up sloping tunnels to existing underground primary crushers. To maintain production rates, such vehicles must be high-powered so that they can transport large payloads uphill at a reasonable speed. As well, all such vehicles must be of low weight, low profile, highly manoeuvrable and should generate minimum noise, heat and noxious gases. Any heat and/or gases generated by underground vehicles only places an extra burden on the mine ventilation/cooling system. The Kiruna electric truck This old photograph shows one of the GE 100-tonne diesel electric dump trucks used in a South African copper mine. The overhead trolley wires gave an electric boost to the trucks as they drove up the steep access ramp. 86 · SILICON CHIP To meet such a need, the ABB company (ASEA-Brown Boveri), in cooperation with Kiruna Truck AB of Sweden, produced a very special electric dump truck in 1985. It amply fulfilled the above criteria, with the flexibility only a rubber tyred vehicle can provide. Although a large vehicle, its low cross section and small turning radius allow it to easily negotiate underground tunnels. In addition, the Kiruna truck is designed for most types ofloaders. Front loaders, side dumping buckets, Joy loaders and even small power shovels have all been successfully employed. Mount Isa Mines has purchased two Kiruna electric trucks and may obtain more, because of their ad- vantages over other types of rubbertyred load shifters. The Kiruna electric truck model K1050E is a 4-wheel drive vehicle powered by two 230kW DC locomotive traction motors. Electric power at 1000V 3-phase 50Hz is provided by an overhead assembly of three parallel conductors, together with two steel guide rails. As shown in one of the photos accompanying this article, the two outer grounded steel rails support sets of porcelain insulators which hold the three live overhead conductors. The truck makes contact with these conductors using a hydraulically hoisted multiple trolley pole. The driver can automatically raise the boom and accurately connect to the overhead wiring in 3-5 seconds. And that can be done even when the truck is not squarely below the conductors above. Because most deep hard rock mines have high ambient temperatures, the Kiruna truck includes air conditioning for the driver's cab, the computer and control boxes and the battery compartment. - J ,,,,, i!~ ---.... t.if.,,~-•i. fl ' ' .. The overhead system The overhead conductor assembly is of simple lightweight construction. The grounded outer steel members are of square section and are mounted cornerwise. These form the sup-port frame for insulator brackets which support the three live phase conductors, each a copper tube 50mm in diameter. The whole structure is bolted to the tunnel ceiling at 5-metre intervals. The minimum radius of curvature of the overhead trolley line is 15 m,etres. The current requirement is approximately 400-500 amps per truck, allowing for acceleration and uphill running. The trolley line is divided into 1km sections, each supplied at its centre by a 1600kVA transformer. The design provides for any section to power either three trucks running or two trucks accelerating uphill. The supplies to each section are set in the same phase rotation and in phase to allow trucks to run through section junctions at full speed. Control system The motor control uses a microcomputer system, high-powered This photo shows the Kiruna electric truck and the 3-phase electric supply on the mine roof. With electric trucks such as these, there is little noise or heat and no air pollution - all important considerations in an underground mine. thyristor converters and chopper circuits. The microcomputer is also used to accurately align the boom when the driver raises the trolley pole to make contact with the overhead conductors. A thyristor converter produces a variable 0-1200V DC rail from the 1000V 3-phase supply. The two 600V DC traction motors are connected in series, one motor driving each axle through planetary and differential gears. Each motor has its fields connected in series with the armature, giving immense starting torque proportional to the square of the starting current. Once accelerated on level track, the fields can be weakened, allowing the motors to run up to a maximum of 2000 RPM. During acceleration, the control sys- tern allows the motor current to rise to 600 amps. The vehicle is rated at 650kW for 30 minutes, reducing to 460kW continuous. Overhead trolleyline The act of attaching the trolleypole to the overhead lines is a veritable work of art in engineering design. This part of the development program was not at all easy. As the diagram of Fig.1 shows, the square steel bars hang lower than the conductors. With the electric contacts withdrawn (as a cat withdraws its claws), the trolleypole is raised, at first contacting the steel sections. Magnetic sensors establish the degree of misalignment. The computer then actuates small horizontal hydraulic rams to rotate the contact head until it is NOVEMBER1991 87 controllers in the truck in the correct sequence. MINE ROOF PORCELAIN INSULATORS ,.......~-,.--,------r----r7-\;.-~-~~ ooov ..,/ '1 LIVE 50mm COPPER TUBES Battery backup - FIXEO OVERHEAD STEEL VERTICAL HYDRAULIC RAM LIFTS CONTACTS - TROLLEYPOLE 3-PHASE 1000V SOHz TO TRUCK Fig.1: this diagram shows the main components of the 3-phase pickup system used by the Kiruna electric truck. The trolleypole is actuated and aligned by computer before the carbon brushes make contact with the lkV 3-phase supply. aligned with the overhead conductors. Finally, a vertical hydraulic ram raises the set of three separately insulated contacts. The actual connection to each overhead live copper tube is made via double carbon brushes , while multiple springs set the contact pressure. Phase rotation Because the truck may be facing in any direction before attempting overhead contact, once connection is made, the 3-phase supply as picked off by the trolleypole may be in forward or reverse rotation. Therefore, before connecting the current to the thyristor motor controllers , the computer first tests the supply phase rotation direction. It then closes either a forward or reverse electromechanical contactor, thus connecting the 1000V 3-phase supply to the thyristor motor !.E.,,;. ;r..~t.:.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. 88 SILICON CHIP A large 250 volt 70 amp-hour traction battery of nicad cells mounted in the truck enables it to be driven outside the range of the overhead trolley line. In this mode, it is limited to one quarter full speed and a range of about 200 metres. This is used during loading, unloading and at intersections. The on-board computer also monitors the battery charge condition and regulates charging current when operating on the overhead power. The actual battery power available for offline running depends on the amount of time the truck has just spent running on the overhead power, charging the batteries. The battery is also used for vehicle lighting, powering the computer and the pumps for the hydraulically activated trolleypole, and for truck dumping. The battery circuits operate through a separate chopper isolated from the 1.2kV system. Performance The Kiruna electric truck weighs 35 tonnes empty and can carry a 50tonne payload. Fully loaded at 85 tonnes gross weight, the truck can travel at 18-20km/h up a 12% incline - twice the performance of a diesel truck of similar capacity. Rated top speed is 50km/h. Other important characteristics are that the electric truck is very quiet, is pollution free and generates very little heat. These last attributes are extremely important in deep mines. Down there, the ambient temperature is already quite high, requiring a general mine cooling and ventilating system. Kiruna diesel truck For applications where overhead electric power is impracticable, ABBKiruna provide two diesel truck models of unique design. They both use front wheel drive , thus eliminating problems of bulky differentials, planetary gearing and intermediate shafts. Interestingly, the truck body doesn't just hold the load but is also part of the exhaust system. Firstly, the exhaust gases flow through cooling coils mounted in the body, then pass into the scrubber which contains a large volume of cold water. The poisonous nitrous gases in the exhaust are far more soluble in cold water. The hot gases do heat the water but such is the volume of the water that it does not reach boiling temperature. Therefore , no steam is ejected. Every second shift, the scrubber is flushed and refilled with cold water. Thus, there is no need for continual topping up. This cold water scrubbing process acts as a purifier, removing 95 % of all hydrocarbons and carbon monoxide from the exhaust gases. Also extracted are 95 % of the aldehydes, acroleins and formaldehydes present in diesel exhaust fumes. Unless removed, these toxic gases would be injurious to the eyes, noses and throats of the miners. Electric versus diesel Whether to choose the electric or diesel trucks is a question which must be considered for each project, as circumstances vary. In some mines, the installation of the electric trolley line may be a deterrent. But in others, the high cost of diesel fuel and extra ventilation systems may sway engineers in favour of electrics. Then again, the electric truck carries the greater payload. Variants of the Kiruna truck are also made for use in other materials handling applications, such as in steel works . OVERHEAD TROLLEY WIRES ABOVE RAMP +750V NEG ELECTRIC ASSIST CIRCUIT 4 TRACTION MOTORS STANDARD DIESEL ELECTRIC TRUCK SYSTEM 3-PHASE BRIDGE RECTIFIER Fig.2: this diagram shows the trolley system and 750V DC boost used to assist diesel electric dump trucks operating in an open cut mine with a steep access ramp. Early GE trucks Though open-cut mining may look like a straightforward operation, some giant-sized problems arise. The common practice is to have very large diesel-electric trucks loaded on the floor of the open cut, then driven up the steep ramp to ground level. In one application at the Palabora copper mine in South Africa in the late 1960s, as the mine deepened the slope became too great for the biggest trucks to climb up the ramp and out of the pit. Therefore, the GeneralElectric Company of the USA designed and built an attachment to a standard 100-tonne capacity dump truck. Each wheel is driven by an independent DC electric motor, all powered by an alternator driven by the supercharged diesel engine. High current rectifiers provided a heavy DC supply for the traction motors, using techniques similar to those employed in diesel-electric locomotives. Some mines use the Kiruna diesel truck and these need to be equipped with a complex exhaust gas absorbing system to ensure that pollutants do not enter the mine. They are more expensive to run, are noisier and not as powerful as their electric counterparts. This arrangement provided ample drive for running around the roughly level floor of the open cut pit but extra power was needed to climb the ramp. DC series traction motors can supply enormous power for short times but the limiting factor in this case was the diesel engine. To solve the power problem, twin overhead electric trolley wires were installed above the ramp roadway. These were supplied with 750V DC by a transformer and rectifier system. The truck was loaded and ran across the pit floor under its own power. Upon reaching the ramp, the driver simply raised the trolley poles to contact the overhead DC supply lines; this was done without stopping. This electricity source then provided much more current to drive the traction motors to full power. After reaching the level ground surface, the driver lowered the trolley poles and continued to the dump site self-powered. Acknowledgements .Thanks to ABB Action, ASEA Journal, John Burton and General Electric for information and photos. SC NOVEMBER 1991 89 Silicon Chip BACK COPIES 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 ; What Is Negative Feedback, Pt.3; Amplifier Headroom - Is It A Con? 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. Ironic Appliances ; Using Comparators to Detect & Measure. August 1988: Buildi r,,g 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. 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. 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. January 1989: Line Filter For Computers; Ultrasonic Proximity Detector 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; Marantz LD50 Loudspeakers. 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. September 1988: Hands-Free Speakerphone; Electronic Fish Bite Detector; High Performance AC Millivoltmeter, Pt.2; Vader Voice; Motorola MC34018 Spe;;ikerphone IC Data; National Semiconductor LM12 150W 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 ; Queensland's Powerful Electric Locomotives. 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 & Elec- 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. Use this handy form to order your back copies l --------- - - ----------------------- ---7 Please send me a back issue for: 0 October 1988 0 November 1988 O March 1989 O April 1989 O August 1989 O September 1989 O January 1990 O February 1990 O June 1990 O July 1990 O November 1990 O December 1990 0 April 1991 0 May 1991 O September 1991 O October 1991 0 O 0 0 0 0 July 1988 December 1988 May 1989 October 1989 March 1990 August 1990 o January 1991 O June 1991 O August 1988 O January 1989 o June 1989 0 November 1989 0 April 1990 o September 1990 o February 1991 0 July 1991 0 0 0 O 0 0 0 O September 1988 February 1989 July 1989 December 1989 May 1990 October 1990 March 1991 August 1991 Enclosed is my cheque/money order for $______or please debit my: O Bankcard Card No. $5.00 each (includes p&p). Overseas orders add $1 each for postage. NZ orders are sent air mail. Signature _ _ _ _ _ _ _ __ ____ Card expiry date_ _ /_ _ Detach and mail to: SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROY BEACH NSW 2097 _Name ______________________ ______ Street _ _ _ _ _ _ _ __ __ _ _ __ _ _ _ _ _ _ _ __ Suburb/town ______________ Postcode ______ 0 Visa Card O Master Card Or call (02) 979 5644 & quote your credit card details. Fax (02) 979 6503 l I I ------- ---- -----------------------------~-90 SILICON CHIP Metres; Phone Patch For Radio Amateurs, Pt.2; PC Program Calculates Great Circle Bearings. March 1990: 6/12V Charger For Sealed LeadAcid Batteries ; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. 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; Active CW Filter For Weak Signal Reception. June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586); Passive Loop Antenna For AM Radios; Universa l Temperature Controller; Understanding CRO Probes;.L.ED Message Board, Pt.3. May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors; The Mozzie 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. 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 Electric Locomotives. 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 A Computer; What To Do When Your Computer Goes Bung , Pt.2. 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 ; Modern 3Phase El ectric Locomotives. July 1990: Digital Sine/Square Generator, Pt.1 (Covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; Low-Cost Dual Power Supply; Inside A Coal Burning Power Station ; What To Do When Your Computer Goes Bung, Pt.3; Weather Fax Frequencies. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC13024 and TX7376P) Pt.1 ; AlarmTriggered Telephone Dialler; High Or Low Fluid Level Detector; Simple DTMF Encoder; Studio Series 20-Band Stereo Equaliser, Pt.2; Auto-Zero Module for Audio Amplifiers (Uses LMC669); A Guide To Hard Disc Drives. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); 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. October 1989: lntrcid~cing Remote Control; FM Radio Intercom For Motorbikes (Uses BA1404 & TDA7000) Pt.1 ; GaAsFet Preamplifier For Amateur TV; 1Mb Printer Buffer; 2-Chip Portable AM Stereo Radio , Pt.2; Installing A Hard Disc In The PC ; A Look At Australian Monorails. September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs ; Power Supply For Burglar Alarms; Low-Cost 3Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band . November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY and Morse); Super-Sensitive FM Wireless Microphone; 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. October 1990: Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; The Dangers of Polychlorinated Biphenyls; The Bose Lifestyle Music System; Using The NE602 In Home-Brew Converter Circuits. December 1989: Digital Voice Board (Records Up To Four Separate Messages); UHF Remote Switch; Balanced Input & Output Stages; Data For The LM831 Low Voltage Amplifier IC ; Install A Clock Card In Your PC ; Index to Volume 2. November 1890: Low-Cost Model Train Controller ; Battery Powered Laser Pointer; A Really Snazzy Egg Timer; 1.5V To 9V DC Converter; How To Connect Two TV Sets To One VCR; Introduction To Digital Electronics ; Simple 6Metre Amateur Transmitter. 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. December '990: DC-DC Converter For Car Amplifiers; The Big Escape -A Game Of Skill; Wiper Pulser For Rear Windows; Versatile 4-Digit Combination Lock; 5W Power Amplifier For The 6Metre Amateur Transmitter; The Great Green CD Pen Controversy; Index To Volume 3. February 1990: 16-Channel Mixing Desk; High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 January 1991: Fast Charger For Nicad 8:>.tteries, Pt.1; The Fruit Machine ; Two-Tone Alarm Module; Laser Power Supply; LCD Readout For The Capacitance Meter; How Quartz Crystals Work ; The Dangers When Servicing Microwave Ovens; Electric Vehicles - The State Of The Art. February 1991: Synthesised Stereo AM Tuner, Pt.1; Three Inverters For Fluorescent Lights; LowCost Sinewave Oscillator; Fast Charger For Nicad Batteries, Pt.2; How To Design Amplifier Output Stages; Tasmania's Hydroelectric Power System. March 1991: Remote Controller For Garage Doors, Pt.1; Transistor Beta Tester Mk.2 ; Synthesised AM Stereo Tuner, Pt.2 ; Multi-Purpose 1/0 Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateurs & TV ; A Look At Config.Sys & Ansi.Sys; High-Voltage DC Transmission Systems. April 1991: Steam Sound Simulator For Model Railroads; Simple 12/24V Light Chaser; Remote Controller For Garage Doors, Pt.2; Synthesised AM Stereo Tuner, Pt.3 ; A Practical Approach To Amplifier Design, Pt.2; Playing With The Ansi.Sys File; FSK Indicator For HF Transmissions. May 1991: Build A DTMF Decoder; 13.5V 25A Power Supply For Transceivers ; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1; Motors For Electric Vehicles. June 1991: A Corner Reflector Antenna For UHF TV; Four-Channel Lighting Desk, Pt.1; 13.5V 25A Power Supply For Transceivers ; Active Filter For CW Reception ; Electric Vehicle Transmission Options; Tuning In To Satellite TV , Pt.1. July 1991: Battery Discharge Pacer For Electric Vehicles; CD Error Analyser, Pt.1 ; Loudspeaker Protector For Stereo Amplifiers ; Four-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets , Pt.2; Tuning In To Satellite TV, Pt.2; PEP Monitor For Transceivers; The Snowy Mountains Hydroelectric Scheme. August 1991: Suild A Digital Tachometer ; Masthead Amplifier For TV & FM ; PC Voice Recorder; Error Analyser For CD Players, Pt.2 ; Tuning In To Satellite TV, Pt.3 ($1000 Satellite Ground Station Reviewed); Installing Windows On Your PC ; StepBy-Step Approach To Vintage Radio Repairs. September 1991: Studio 3-55L 3-Way Loudspeaker System; Digital Altimeter For Gliders & Ultralights, Pt.1; Build A Fax/Modem For Your Computer; Ultrasonic Switch For Mains Appliances; The Basics Of AID & DIA Conversion. October 1991: Build A Talking Voltmeter For Your PC; SteamSound Simulator MK.II ; Magnetic Field Strength Meter; Digital Altimeter For Gliders & Ultralights, Pt.2; Getting To KnowThe Windows PIF Editor. PLEASE NOTE: All issues from November 1987 to June 1988 are now sold out. All subsequent issues are presently in stock. For readers wanting articles from issues out of print. we can supply photostat copies (or tearsheets) at $5.00 per article, including posto.Q6. w,-,en supplying photostat articles or back copies, we automatically supply any relevant Notes & Errata at no extra charge. NOVEMBER 1991 91 ASK SILICON CHIP Got a technical problem? Can't understand a piece of jargon or some technical principle? Drop us a line and we'll answer your question. Write to:Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097. Different transformer for power supply I am considering building the 25 amp switchmode supply described in the May and June 1991 issues of SILICON CHIP. Before I start, could you answer a few questions? (1). Can another suitably rated transformer be used or does the circuit require the specific toroidal transformer by Harbuch Electronics? (2). Have there been any amendments to the circuit as published. If there are such changes, could I get a copy? (3). Who, or what, is "NSD" as a source of 70HFR20 stud diodes and likewise for "VSI" for MAC320A8FB Triacs? (L. M., New Lambton, NSW). • The circuit does not require a toroidal transformer although naturally a conventional transformer of equivalent rating is likely to be very much larger and may not fit in the case. The circuit definitely must be built around the two chokes supplied by Harbuch Transformers. There have been no alterations or corrections to the circuit. NSD Australia and VSI Electronics Australia Pty Ltd are the agents for the compo- Low voltage hiccup with train controller I am writing regarding the "Low Cost Model Train Controller" described in the November 1990 issue of SILICON CHIP. Having made up three units and given them a hiding at the 1st Brunswick Heads Exhibition, then the Brisbane Exhibition, I feel some feedback may be useful. One unit failed at Brisbane due to an open circuit LED, which in turn burnt the two 1.Q resistors and the TIP41 transistor due to failure of the current trip. Subsequent testing after the repair showed that if the input volt92 . SILICON CHIP nents listed. They both have cash sales counters. NSD's phone number is (008) 335 623. VSI's phone number is (02) 439 8622. Radio beacon for a car The other day, my wife and I went bush (spinifex!) and, after walking around, my navigation dead reckoning was out by about 0.5km to the car. No panic, but the problem was that we could have been in a very different position. Anyway, is there any form of project where a vehicle or whatever can put out a signal that a hand-held pointer can home in on? I'm thinking of something like a direction finder that has a needle pointing to the source, with a range of 1km or so. I have read as much as I can but cannot find a scrap of information on this subject. Or am I talking James Bond spy stuff? (J. K., Paraburdoo, WA). • Your idea is not new but we don't know of any commercial product which would suit. There are, of course, .a number of emergency beacons which are used at sea but these would not age is lower than about 12 volts, then the maximum output current can rise above 1.3 amps. In some cases, if the input voltage is only 6 volts, then the current can exceed 3-5 amps! The cause of low input at high output current can be caused by a damaged high resistance fuse! (S. D., Stokers Siding, NSW). • Your comments about excessive current being delivered when the input voltage is low are interesting. It would seem likely that the short circuit protection does not work because there is not enough voltage to allow the LED to conduct. be applicable to your situation. The best we can suggest at the moment would be to set up a CB radio and have it put out a pulse every 10 seconds or so on a designated channel. If readers are interested in this concept, we may do a project on it in the future. Problems with computer compatibility I have had trouble getting my printer, a Tandy TRP100, to work with my Amstrad 1640 computer, via the parallel port. The trouble is that the Amstrad calls pin 31 of the printer connector !NIT, while on the Tandy machine it is pin 33. I cured the problem by changing over the wires to pins 31 and 33 at the printer connector in the printer cable. Which is right, the printer or the computer? (J. J., Engadine, NSW). • The problem with the connector is not so much whether the computer or the printer is right but the loose standard of the Centronics parallel interface. Because the standard is not very tightly defined, it does mean that there can be problems of incompatibility, as you have found. The same problems occur with the RS232 serial interface. Modifying the alarm sector boards Sometime ago, I constructed the add-on sector boards (intentionally without the control board) for the alarm system described in the June 1990 edition. These have been used successfully to monitor several gates around the perimeter of my house. I have -connected a PNP transistor to two of the 4049 inverter's outputs (pins 6 & 10) which control a small piezo alarm and light a LED to indicate which gate is open. The trouble is, if a gate is left opened for an extended period, the continual ringing of the buzzer becomes annoying. I have tried to use a speaker de- thump circuit to turn off the buzzer but as the circuit switches high after approximately 5-6 seconds and not low, I have found it difficult to modify them without the use of a relay. Ultimately, I aim to complete the system without moving parts. If not too much trouble, could you please suggest how to modify the circuit to solve the problem. (T. T., Geelong, Vic). • It appears that you really need a time-out circuit which is triggered when one of the gates on your property is opened. We suggest you use the monostable circuit involving IC9b (or a 555) on page 35 of the same issue. The 555 could drive the buzzer and a LED but would need a negative pulse at its pin 2 terminal to trigger it. Your present 4049 circuit should do that. Speak!?rphone has tunnel effect Discolight clock runs faster than the beat I recently built the Discolight as des~ribed in the July and August 1988 issues of SILICON CIITP. No serious problems were encountered - in fact, the unit in most respects surpasses commercial units costing much more, or should I say it would if we could solve one small but perplexing difficulty. This involves the method of generating a clock pulse from the bass beat of the music. In the unit I have constructed, exclusive-OR gate IC5 produces a pulse and advances counter IC6 on every rise or fall of voltage at S5 , with the result that each music beat flashes two lights rather than one. This does not really achieve the desired effect. The same thing is happening with the oscillator however this is not directly observable by watching the pattern. I assume that the intention was only to clock positive transitions at S5 but I cannot see how this is possible with the circuit as it stands. I have just completed the "HandsFree Speakerphone" project from the September 1988 issue and I would like your advice, as to the reason my voice, when heard by the other person on the other end of the phone, sounds like I'm in a tunnel. It is not like listening to somebody using the normal telephone. Adjusting the volume makes no difference to the effect. (D. C. , Naranga, Qld). • It is normal for the user to sound as though he is in a tunnel or a large drum. This is because the Speakerphone microphone is picking up reverberant sound from the room. By contrast, an ordinary telephone has a "close mic" characteristic and does not pick up reverberant room sounds. You can minimise the reverberation problem to some extent by sitting the Speakerphone on a cushion or piece of carpet. By the way, all hands-free telephones have the same characteristic. Are there any other ways to prevent this problem, since most compounds of lead are dangerous? (R. P., Blacktown, NSW). • Normal solder fumes are generally regarded as non-toxic, although we certainly don't like breathing them ourselves. On the other hand, low temperature solders which may be alloyed with cadmium are extremely dangerous if the temperature of the soldering iron is too hot. These must be used with a temperature controlled soldering iron on a low setting and with good ventilation. Are soldering fumes dangerous? Triac dimming characteristics Here is a question that has been with me for some time now: is the smoke and fumes from solder dangerous to one's health? I try my best not to inhale any fumes but it seems that I always manage to. I have a small fan that blows across anything I solder but this makes the solder more difficult to use since the breeze cools it. I would like to draw your attention to the article on the Discolight in the July and August 1988 issues of SILICON CHIP. I am very interested in this article and the associated article in the October 1990 issue on adding dimming controls. I am a student at Mount Lawley TAFE, Perth, studying Electronic En- I can see that an output is produced from IC5 when pin 5 goes high and terminates when pin 6 goes high shortly after due to the time constant circuit used. It seems to me that when the voltage from diode D5 falls back to 0V, pin 6 will remain high long enough to produce another pulse. To eliminate the possibility that the problem is due to faulty components or tolerance problems , I have replaced IC5 and its associated components without any change in the results. Have I misunderstood the operation of this part of the circuit or have I missed some other possible explanation? (J. P., Everton Hills , Qld). • The circuit as published has been found to work satisfactorily with most music signals although your analysis would seem to in dicate that IC6 would be clocked twice by every beat of the music. If you wish to change this, you need to disconnect pin 5 of IC5 from diode D5 and connect it to the 0V rail. gineering. I have been studying these articles which you published because I am going to build the Discolight but I am going to design some new features into it. I would be extremely grateful if you could send me as much information on the Discolight and dimming circuits as possible, with emphasis on the effect that dimming circuits have on the voltage supplied to the lamps. (K. M., Thornlie, WA). . • Unfortunately, we are not able to provide any additional information on the dimming circuitry apart from the comment that the control action is more or less linear with respect to the Triac firing angle, not to the brightness ohhe lamp. If you consult a text on theatrical light dimming you will find that there are a number of suggested dimming characteristics to suit stage, TV and disco applications. As far as the lamp voltage is concerned, it is very non-linear. A relatively small change in voltage applied to the lamp causes a big change in brightness. NOVEMBER 1991 93 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon· Chip. r-------------------------, ANTIQUE RADIO CLASSIFIED ADVERTISING RATES ANTIQUE RADIO restorations. Your one-stop radio repair shop. Specialising in restoring vintage radios including chassis rewiring, re-condensing, quality new parts, valves, valve sockets, speakers, power & audio transformers. Secondhand radio dials & parts for most brands & models. About 400 radios in stock for sale, restoration & parts. Every restored wireless is covered by a 2year warranty on parts & labour. We restore damaged woodwork & cabinets & French polish (approx. 40 coats). Vintage car radios available for sale or restoration. Repairs done on tape decks & amplifiers. Open Sat. 10am-5pm; Sun. 12.30-5pm. 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or (02) 726 1613 AH. 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. To run your classified ad, print it clearly on a separate sheet of paper & send it with this form & your cheque or credit card details to : Silicon Chip Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02) 979 6503. FOR SALE Enclosed is my cheque/money order for $_ _ _ _ or please debit my o Bankcard O Visa Card o Master Card I I I I I I I I I I :k I ~~I l___,~____,I ~I'----'-----'----'I I~ '---'------'----' I I Signature_ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _-'/_ __ I I Name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ I I Street - - - - - - - - - - - -- - - - - - - - - - I Suburb/town _ _ _ _ _ _ _ _ _ _ _ _ Postcode- -- - - - I I L _________________________ J 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 & 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, 4004 Old. Phone (07) 358 2785. Card No. 94 SILICON CHIP IBM COMPATIBLE computer kits & accessories. Button spike protector $37.00. 6-socket power boards with surge/spike protection $49.00. Pack/ post $3.00. Send for a free price list. M.T.S. Electronics, PO Box 1013 Taree, NSW 2430. Phone (065) 53 1296. $115 OFF THE WORLD's first MSDOS Pocket PC. Australia's best price , ...._ MEMORY EXPANSION LEARN ELECTRONICS WITH UCANDO VIDEOS Prices at October 1, 1991 AC-DC power supplies, amplifiers, integrated circuits, oscillators. Average one hour each. $A48.00 each. Also build electronic kits for learning experience. SIMM 1MB x9 100ns 80ns 1MB»8 100ns 80ns 4MBx9 80ns 256 X 9 80ns (ForSIPadd$1) Mastercard & Visa accepted. DRAM-DIP 1MBx1 80ns 256 X 4 100ns 80ns 41256 120ns 100ns 80ns Electronics Assembly Co, PO Box 21191, Edgeware, Christchurch, New Zealand. Phone 3-795-570 KIT REPAIRS Kits repaired from all magazines. Switchmode power supplies repaired, design work from start to finish computer software consultancy. Ring anytime 9am-9pm Mon-Sun. EEM Electronics, 10 Bouverie Place, Epping, Vic. 3076 Phone (03) 401 1393 TRANSFORMER REWINDS ALL TYPES OF TRANSFORMER REWINDS TRANSFORMER REWINDS 58.00 55.00 48.00 56.00 240.00 16.00 6.00 5.90 6.00 1.80 2.00 2.20 PELHAM \.. COPROCESSORS 80387-DX To 33 80387-SX 16 & 20 80287 To 12MHz 80287 Over 12 250.00 157.00 100.00 147.00 FLOPPY DRIVES 3.5 Panasonic 1.44 3.5 Teac 1.44 5.25 Panasonic 1.2 80.00 86.00 92.00 EXPANSION CARDS LS 866N 32Mb OK 240.00 AST RAM plus 8Mb 350.00 BOCA AT plus 8Mb 250.00 Tel (02) 980 6988 SOCKETS Simm Sockets 30 x 1 Vert Simm Sockets 30 x 2 Ang Simm Sockets 30 x 2 Vert 1.70 3.50 3.20 ~ PRINTED CIRCUIT BOARDS FIX-A-KIT PCBs for all SILICON CHIP projects made to order. Prototype & kit repair service available. KIT REPAIR & CONSTRUCTION 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION . TECHNICAL ASSISTANCE HVCAL ELECTRONICS Hours 10-5 Wednesday to Friday, 9-12 Saturday. ETS, PO BOX 491, NOARLUNGA CENTRE, SA 5168. Phone: (08) 382 8919 Design, Manufacture & Repair of Electronic Equipment (02) 633 5477 , MAX 1/0 Board UNUSUAL ITEMS & components: 75mm diameter perspex IR filters $16; 130mm diameter pyrex IR filters $50; collimated 2.5mW IR laser diode assemblies (collimator lens) $45; 680pF/ 3kV disc ceramics at 50 for $1 0; 1On/ 3kV disc ceramics at 10 for $8; 1nF/ 15kV disc ceramics $12; 10kV avalanche diodes $1; used regulated 15kV 500µA EHT power supplies $45; 1mW 800nm IR LEDs at 10 for $3.50; dual element pyroelectric sensors with Fresnel lens $9.90. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02} 579 4985. 300.00 180.00 100.00 168.00 305.00 250.00 206.00 Fax (02) 980 6991 • 7 x Relays SPST 2 amps each • 8 x Switch inputs (TTL) • 1 x DAC (Digital to Analog converter) • 1 x ADC ( Analog to Digital converter) • 4 x Motor Drive outputs (40mA ea.) • 1 x Programmable timer output. MAX includes a 20-page manual with all schematics, parts layout etc., a 360K PC-compatible floppy with diagnostic and sample software in GW-Basic. MAX runs from a PC compatible printer port for full compatibility with a large range of computers. Same day dispatch of orders. Credit cards or personal cheques welcome. Phone (08) 332 6513 or Fax (08) 364 0902 (24 hours) PC Computers, 36 Regent St, Kensington, SA. CRYSTAL LOCKED ULTRASONIC movement detector kit. Compact reliable unit, see EAApril 1990, reduced by more than 20%: $27 for the complete kit with the onboard transducers, $35 for the same kit with the prewired free mounting transducers. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. CAR ALARM: top of the range, ready made, well known brand, commercial car alarm. UHF remote with two keys supplied, flashes vehicle blinkers for indication and during alarm, voltage drop detector, can be wired to existing door UNIDEN SCANNERS DON'T PAY MORE! 50XL RRP $299.95. Our price $211 10 memories, Lo-Hi VHF, UHF Kit $149.00. Built & Tested $269.00. PROFESSIONAL KITS & products. Ampl ifiers, power supplies, test 1equipment, PC driven devices & surplus parts. Send SASE for list to: Al Younger, 5/22 Albert St, Edgecliff, NSW 2027. 4Mb 1Mb 1Mb 2Mb 4Mb 4Mb 2Mb Sales Tax 20%. Overnight Delivery. Credit Cards Welcome 1st Floor, 100 Yarrara Road, Pennant Hills, NSW 2120. Reply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph : (065) 761291. Fax: (065) 761003. on Atari Portfolio $380 incl. tax, postage & insurance. 80C88 CPU, video cassette size. Lowest prices on accessories. For more info, send a 43c stamp to Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. SPECIALS Sun SLC Sharp 6220 Sharp 8081 PS/2(ALL) PS/2(ALL) Mac FX/NIX Laser Printers 100XLT RRP $449.95. Our price $409 100 memories, Lo-Hi VHF, Air, UHF 200XLT RRP $549.95. Our Price $477 200 memories, Lo-Hi VHF, Air, UHF, 800 MHz All prices include delivery. Phone anytime today! (03) 883 9535; Fax (03) 432 0716 ~ TopCom Communications PO Box 336, Greensborough, Vic 3088. ~ switches, 120dB siren, back up battery, ignition cutoff, flashing LED supplied, instructions and all installation items such as the bonnet/boot switches and wiring loom are supplied. You could pay over $600 for an alarm like this but we can supply this alarm and a Crystal Locked Ultrasonic kit for a total of $269! Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. BIGGER LASER BARGAIN: for the bigger displays, discos, etc. A high quality Hugh~s brand, low divergence 10mW He-Ne tube, supplied with our 12V Universal Laser Supply kit at an incredible NOVEMBER 1991 95 Market Centre - continued from page 95 Advertising Index Adilam Electronics .... .. ........... OBC Altronics ................................ 28-31 Antique Radio Restorations ....... 94 Av-Comm ........................ .... ....... 25 Back Issues .................... ...... 90,91 David Reid Electronics ........ 2-3,69 Dick Smith Electronics .......... 12-14 SUSIES COMPUTERS EEM Electronics .... .. .................. 95 36 Regent Street, Kensington (08) 364 0902. 75 Main South Rd, O'Halloran Hill (08) 322 4299. Electronic Toy Services ............. 95 Electronics Assembly Co ... ........ 95 price of $400 for the pair. That's . less than half the price of the tube itself. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. INFRARED NIGHT VIEWER: not a complete kit but just the absolute essentials - an tR image converter tube and a ready-made power supply. The supply has approximate dimensions of 105 x 56 x 37mm, draws approx. 35mA from a 9V battery, and can power any IR tube. The tube is a 6032A and the instructions are provided. Giveaway at $150 for the pair. $5 certified p&p. Major cards accepted with phone and fax orders. NZ air-mail $10. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. Fax (02) 570 7910. PC VOICE RECORDER software for project published in SILICON CHIP, August 1991. Plugs into the printer board of any genuine IBM PC/XT/AT/ 386 or compatible. Record up to 20 seconds of sound, save it to disc & replay it in the future. Software only available on 5.25-inch 360Kb disc plus documentation & instructions for $25 plus $3. Talking Clock software also available - turns your computer into a talking timepiece. Only $15 plus $3 p&p. (VGA, EGA, CGA, Mono). Send :,._ cheque or money order to Darren Yates, PO Box 134, French's Forest, NSW 2086. UNUSUAL BOOKS: Fireworks, locksmithing, radar invisibility, surveillance, unusual chemistry and more. Send SASE for catalog to Vector Press, Dept. S, PO Box 434, Brighton SA 5048. SC Elmeasco .. ...... .... .............. .. ..... IFC Geoff Wood Electronics .... .. .... ... 23 Harbuch Electronics ............ .. .... 44 Hycal Instruments ........ ........ ...... 95 Jaycar Electronics ................ 45-52 J.V. Tuners ............................ ..... 43 Kalex ......................................... 81 Kingsley Electronics ...... ....... ..... 44 Oatley Electronics ........... 27,95,96 PC Computers .................. .... .... . 95 PC Marketplace ........................... 7 Pelham ......... :............................ 95 RCS Radio ................................ 88 Resurrection Radio .................. .. 81 Rod Irving Electronics .......... 38,39 58,59,82,83 Subscriptions ...................... ....... 15 r-------------------------, l 1 To: Silicon Chip~u~~:.~~s~P~I ~o~ :,DERS Collaroy Beach, NSW 2097, Australia. i Yes! Please send me _ ___ SILICON CHIP binder(s) at $A11.95 plus $A3 p&p each (NZ $A6 p&p). Enclosed is my cheque/money order for $_ _ _ _ or please debit my D Bankcard D Visa Card D Master Card Card No. Signature_ _ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _~/_ __ Name _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Street _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Suburb/town _ _ _ _ _ _ _ _ _ _ _ _ Postcode_ _ _ _ __ L _________________________ J 96 SILICON CHIP Susies Computers .................. ... 96 TopCom Communications .... ..... 95 Transformer Rewinds ................ 95 Yokogawa ...... ........................ .. IBC PC Boards Printed circuit boards for SILICON CHIP projects are made by: • Electronic Toy Services, 2/111 Glynville Drive, Hackham West, SA 5163. Phone (08) 382 8919. • Jemal Products, 5 Forge St, Welshpool, WA 6106. Phone (09) 350 5555. • Marday Services, PO Box 19-189, Avondale, Auckland, NZ. Phone 88 5730. • RCS Radio Pty Ltd, 651 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491. YOKOGAWA ♦ \ 1 ! ► ► 12Bk MAXIMUM RECORD LENGTH 100 MHz ANALOG BANDWIDTH ► ► B BIT VERTICAL RESOLUTION - , - - - , , -- ;- l l L _ _., '----- VIOi\/ , 1 I 4 FULL CHANNELS 100 MS/ e MAXIMUM SAMPLE RATE - VION ► ' VIDIV VIIJW CPO$ft1QN ~ 1'0$/NON l L_ _______ ,-._____ ."°" ,-, ,-, ,....., ,-, ,-, ,-, r , ~ POl,ITKJN ~ t: 128K RE::COF1D LENGTH All This Measurement Capability For $6900* Capture and view detailed information over long time intervals easily with the DL 1200 's 128k record length and 100Ms/sec sample rate, 300 page Test & Measurement catalogue available Capture up to 4 simultaneous events to speed the analysis of complex digital systems with the Yokogawa DL 1200 YOKOGAWA Worst case jitter measurements become a simple matter using the DL 1200's Dynamic Accumulate Mode, Increase your measurement repeatabi lity using the DL 120Ll's Automatic Measurements Call (02) 805 0699 Tor brochure now! Centrecourt D3, 25-27 Paul Street North, North Ryde Private Mail Bag 24 P.O . North Ryde N SW 2113 Phone : (02) 805 0699 Fax : (02) 888 1844 · Pri nter & Memory Card Extra