Fullscreen HTML5Med Res (??MB)HTML4

Getting The PIF With Windows - AUSTRALIA'S DYNAMIC ~ ELECTRONICS MAGAZINE~ SERVICING - VINTAGE RADIO - COMPUTERS - AMATEUR RADIO - PROJECTS TO BUILD Digital Altimeter The full circuit details CI-118A 20MHz Dual Trace Os,;ilJ◄~s 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 calibrated steps with 1-2-5 seq.) ■ ■ ■ mV /DIV: Accuracy, %: Max. input (AC/DC) V: -- . .._-,'"J, - ...,. ~ ..""- r. -:, Bel .. 5-10 ' .. +/ - 4 .. 250 Input Impedance, Mohm/pf: ■ ■ ■ DC coupled input: with external divider in position 1:10 with external divider 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 external synchronization, V, Max.: ■ lOHz to 20MHz .. 0.2 Typical external synchronization ■ Input Imp. kohm/pf Note: for Government Dept's, Schools, Sales Tax No. holders, etc only $430.43 ea. (ex-tax) - ollicial order must be produced .. 70/15 Available from: David Reid Electronics Universe Computers 127 York Street, 127 Melbourne St, SYDNEY N.S. W. 2000 Nth ADELAIDE S.A. 5007 Ph: (02) 267 1385 Fax: (02) 261 8905 Ph: 018 292080 Fax: (08) 332 1617 {Mai/orders welcome) {Mai/orders welcome) The meter you all been waiting tor!! FLUKE 79 SERIES II MULTIMETER ■ Capacitance measurement. ■ Frequency measurement. ■ Fast analog bar graph. ■ 4,000 count display. ■ Automatic Touch Hold. ■ 0.3% basic accuracy. ■ Continuity beeper. ■ All inputs protected. ■ 3 year warranty. CDA 1FM Stereo Transrnitter * Input: 3.5mm plug. * Tuneable 89 - 91 MHz. * Range: 100 meters/15mV * Power: 1 x AAA battery. * Temperature adjustable: 200 - 480 deg. C. * 24voll o 50 watt element. * Ceramic heati ng element. * Control accuracy:+ /- 5 deg . C. * Large range of spare tips available. Now$49.95 S8'19 * Made in Japan. * 12 months warrany. $20.00 •why buy a kit at this pries• Automotive PORTABLE CD MOUNT The POS1 Portable Oisc Shuttle with the new NAVCOM suspension system allows you to mount your DiscMan in your car and virtually eliminates skipping or mistracking. Complete with swivel base, platform, brackets and all mounting hsrwsre. Made in U.S.A. * NEVV LOVV PRICE HAKKO 926/50 SOLDERING STATION only $199.00 Adjustable Bench Regulated POVVER SUPPLY 0-30 volt DC<at> 0-5 amps Reverse polarity protection. Current Limiting. Dual Meters. Fully Built only$49.95 only "What a Brilliant Idea" $199.00 Model: APS305 4 ZONE "KEYPAD" CONTROLLED ALABII SYSTEM "The Control Panel has 4 sectors for N.O. and N.C. inputs, a o amp relay output, horn speakllr output and wore. H is all controlled via a remote keypad, (four wire hook-up). That weans you can bide away the main control panel, out l)f veiw, and operate all your functions via the keypad. All you have to do is 1.o remember your PIN number. A very versitial, hut simple to use alarm system." Alarm Pac~kag" Inc:luclc,s:1 1 1 1 2 1 1 1 1 1 2 1 1 3_6 volt LITHIUM BATTERY * TADIRAN TL-5242/W * Back-up battery for clock on PC. 10 volt AC PLUG PACK * 10 volt AC o 1 amp. * suitable for NetCom * P/R-B612 Pulse Count PIR Detector modems. phone's, etc DC plug fitted. only$59.95 David Reid Bectronics Battery Operated Engraving Tool • Requires 2 AA batteries x Control Panel x x x x x x x x x x x x Remote Keypad Power supply Bac:k-up buttery Pulse-c:ount PIR's Horn speaker siren Internal siren Siren cover Blue strobe Panic button Reed switches l00mtr. cable Instruction manual Car Alarm 276P WARNING INDICATOR • A claytons car alarm · * 12 volt operation. BATTERY (equivalent) only$4.95 * clip to suit $2.50 Post and Pocklng SS - 525 ........ $4.00 526 - SSO ..... . $6.00 $51 - $100 ...... $7.00 $101 • $499 .... 59.00 $SOO • ............ FREE 127 York St. SYDNEY 2000 PH: (02) 267 1385 P.O. Box Q103, SYDNEY 2000 FAX: (02) 2618905 (!~ E' ~·- . SAME DAY MAILORDER DESPATCH* .;;.Din<nOub \~ lnttmlliiond' ' •. -· ! ~ ·' i October 1991 FEATURES THIS MAGNETIC FIELD strength meter features an LCD readout & is capable of measuring magnetic field strengths from 020mT over three ranges. Build it & check the field strengths in your home. Details page 12. 8 Road' Testing The HP54601 A 100MHz CRO by Leo Simpson The first of a new generation 86 The Story Of Electrical Energy, Pt.14 by Bryan Maher Making electrical energy use more efficient PROJECTS TO BUILD 12 Magnetic Field Strength Meter by John Clarke Check your exposure to power line fields 32 SteamSound Simulator Mk.1I by Darren Yates New version fits in the locomotive's tender 54 Build A Talking Voltmeter For Your PC, Pt.1 by Darren Yates It talks and gives an on-screen readout 60 Digital Altimeter For Gliders & Ultralights, Pt.2 by John Clarke ARE YOU INTERESTED in model railroads? This new version of the SteamSound Simulator will work with a wider range of locos & is more compact so that it can be mounted in the tender, rather than a following wagon. See page 32. Second article has the circuit details SPECIAL COLUMNS 20 Serviceman's Log by the TV Serviceman Murphy has two bob each way 42 Computer Bits by Jennifer Bonnitcha Getting the PIF with \l\lindows 68 Amateur Radio by Garry Cratt Optimising HF antennas for multihop operation 72 Vintage Radio by John Hill Two vintage radio museums 80 Remote Control by Bob Young The military applications of radio-controlled aircraft FANCY A VOLTMETER that talks? - just build this simple project & combine it with the PC Voice Recorder described in the August issue. It plugs directly into the printer port of your PC & also gives an on-screen display. Pt.1 begins on page 54. DEPARTMENTS 3 Publisher's Letter 26 Circuit Notebook 40 Back Issues 53 Bookshelf 76 Product Showcase 2 SILICON CHIP 90 Ask Silicon Chip 93 Subscription Page 94 .Market Centre 96 Advertising Index Note: space restrictions have again made it necessary for us to hold over Pt.3 of the CD Error Analyser. This article will now be published in the November issue. Publisher & Editor-in-Chief PUBLISHER'S LETTER Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) 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 Being cautious with electromagnetic fields This month, we are publishing a magnetic field meter with LCD readout. It is intended for measuring the magnetic fields emitted by all mains operated appliances and computer and video monitors. A number of readers have asked us to do a feature on this subject and it is one that is hard to ignore since it has been covered very thoroughly by such eminent journals such as "Electronics World + Wireless World" and "IEEE Spectrum". Up till now though, we have devoted little space to this sensitive subject because the evidence that 50Hz magnetic fields are harmful is still pretty tenuous. Now before all those people who believe that these fields are positively harmful jump up in a rage, let me state that the statistical evidence for such conclusions is "right down in the noise". The message so far seems to be that yes, there is some correlation between exposure to magnetic fields and some cancers and some other biological effects. And since no-one knows what the safe long-term exposure levels are, there is a move to minimise the emissions from all electrical and electronic equipment. Hence, in order to be able to measure these fields, we have published the magnetic field meter. However, having published the meter, we would caution people about becoming paranoid about 50Hz magnetic fields. There are far worse forms of radiation to which we are all exposed and we would be far better minimising those. For example, rather than worry about the very low level of 50Hz fields which might be emitted by your computer or its monitor, consider that your low voltage halogen desk lamp may be emitting high levels of ultraviolet radiation which definitely can harm your vision. To a lesser extent, the same can be said of fluorescent desk lamps. Or when you are out driving in traffic, close your car's windows and put the ventilation or airconditioning on "recycle" so that you are not exposed to carbon monoxide and lead emissions. Compared with these hazards and many others, 50Hz magnetic fields seem pretty innocuous. So by all means, build the magnetic field meter and if you are so inclined, arrange your household appliances to minimise your exposure. But don't go as far as some people and refuse to use appliances at all because of their magnetic emissions. That is being paranoid. Leo Simpson Brendan Akhurst Jennifer Bonnitcha, 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 Pty Ltd. All material copyright ©. No part of this publication may be reproduced without prior written consent of the publisher. Printing: Magazine Printers Pty Ltd, Alexandria, NSW; Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $42 per year in Australia. For overseas rates, refer to the subscription page in this issue. Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or se lling 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 O CTOBER 1991 3 MAILBAG Good report on the high energy ignition system I recently installed a Transistor Assisted Ignition (SILICON CHIP, May 1988) kit in my 1976 Datsun 120Y and am very pleased with it. Last Wednesday, I had the first opportunity of giving the car a proper run to Ballina and back; 80 miles each way. It pulled up hills in top gear better than I can remember and in some cases even at increasing speed. Traffic was light and I was able to keep a steady 80km/h or better when traffic signs permitted. The petrol consumption was 14.75 litres for 245km which is 46.92mpg. The device certainly lives up to your claims and my only regret is that I did not install it years ago. A friend who installed one in his fairly modern van reports much smoother running but the real test will be in September when he will be travelling a long distance. W. A. Easterling, Burleigh Waters, Qld. Stereo AM tuner could have had lower distortion Congratulations on the complex but apparently very successful AM stereo tuner described in the February, March and April 1991 issues of SILICON CHIP. The only gripe I have is not with your project, but with Motorola. They have gone to all the trouble of making a phase locked loop stereo decoder, operating from a reference osc'illator at 3.6MHz, but yet apparently have not provided nearly as much thought to the envelope detector which is "much the same as in a conventional (mono) AM radio". Your specifications published in the June magazine tend to support this with a quoted THD of less than 1 %. Why couldn't Motorola produce a synchrodyne detector? They had the 3.6MHz reference oscillator which is divided down to produce the required signal. All it needed was one extra divider stage to produce a control signal 90° out of phase, which can then be used to control a simple switch. Such an arrangement would produce very low distortion signals, even at 4 SILICON CHIP minimum and maximum modulation of the radio signal. I may be wrong, but if this had been done, I would have expected to see lower distortion figures than you have quoted. Judging by the circuit diagram, it would appear that it is not even possible to adapt the chip to an external detector. D. J. H. Stringer, Christchurch, NZ. Comment: we don't have the answers on why Motorola did not incorporate a better detector into their MC13024. Nor do we know .why they did not go into production with their much better chip set, the MC13022 AM stereo decoder and MC13021 AM stereo tuning stabiliser for which they produr:Ad advanced production samples. Splitters can work as combiners K. T. Andrew asked, in Mailbag for the July 1991 issue, for some information about designing and constructing a "combiner" for MATV distribution. He is no doubt correct in surmising that somewhere there must be information about designing a combiner, but when the exercise was completed, he would have a device exactly like a splitter built back to front! I have been using splitters as combiners for 15 years and have never found need to seek out a different device. I seem to recall that even Hills, the industry leaders, recommend the one device for both services. Just the same, users should be very careful not to mistake a Tee unit for a splitter. A Tee will not work as a combiner, even though it will work after a fashion as a splitter. J. Lawler, Geilston Bay, Tasmania. Guitar preamplifier wanted Some time ago, I wrote a letter regarding the LM12 integrated circuit and its possible use as a guitar amplifier. There has also been some correspondence from other readers in your letters column requesting such an amplifier. A purpose-built power amplifier stage may not be desirable on the SILICON CHIP, PO Box 139, Collaroy Beach 2097. grounds of development costs and inconvenience but a preamplifier on a separate board should be quite reasonable in all regards . Ideally, the circuit should be suitable for all musical instruments, Please (beg, plead, grovel) publish a musical instrument preamp. A truly universal preamp would be well received indeed. Tim Newsom, Balmain, NSW. On fighting noise with noise Whilst sorting through some copies of SILICON CHIP yesterday, I came across your editorial of March regarding "noise'', May I please be permitted to add my thoughts on the matter "from the other side of the fence" so to speak. There is a good reason why we sometimes have to play our high fidelity stereophonic amplifiers so loudly. Around here, supposedly in a very "quiet" area, we have to endure noise from heavy earth-moving machinery (virtually every day); from new house sites (every day of the week); "loud" motor cars every few seconds (virtually everyone has one); noisy neighbours (why is it that the noisiest one always lives next door?); endlessly barking dogs and endless motor mowers (some people are so keen they even mow their lawn in the pouring rain!) . Why do we play the "hifi" so loudly? Because we can't hear it! Anyway, thanks for a great magazine. T. Robinson, Woodend, Vic. Rare issue wanted I would like to be contacted by any reader who has for sale a January 1988 issue of SILICON CHIP magazine. I am willing to pay up to $10.00, provided that the magazine is in good condition. May I also take this opportunity to express my thanks for such a top quality magazine. Keep up the good work. J. Vergios, Rockdale, NSW. Phone (02) 599 2241. 30V VARIABLE POWER SUPPLY QQQ Cost Effective! BARGAIN QQQ BENCHTOP l1J POWER SUPPLY 11] A versatile benchtop power supply that takes a practical approach to what's really required .. . and comes up with a money saving solution. Features include 2.5 to 18V variable output voltage, switchable current limiting (30mA & 1.2A), switchable voltage and current metering ..... and it's all in a compact package. Full form kit is supplied with all components, case and pre-punched silk screened A one amp, fully metered, power supply that's ideal for technicians, designers or hobbyists. It's adjustable up to 30 volts 1 amp with full overload protection and features a current limit LED. It's a full form kit & comes with a sturdy case, all components, PCB & front panel label. Cat K-3475 ETI 11 /82 Now Only Was $99 s7995 ~.";~:;:' Until Sold Out! <at>s191 l~ j Only$89'15 Increase Your 'Talk Power' QQ Q Suitable for 4,6 & 8 Cylinder Cars! SPEECH PROCESSOR FOR TRANSCEIVERS DIGITAL TACHOMETER Watching the rev count on your car is a sure way to maximize afficiency and engine life. This low cost ditigal tacho is certainly the way to go. It's relatively easy to build and it's designed to work with all ignition systems and with 4, 6, & 8 cylinder motors. Short form kit comes with LED display, all components~.a~d PCB. Cat K-3241 g:)JJJ:i!J& ,t;Jf "%.!'f)/ I ~ 8/91 The very effective and successful method for controlling the dynamic range of speech through your transceiver. This simple device fits between the microphone and transceiver acting as a form of compressor so your speach level at the other end is as clear as possible. As a bonus, it automatically generates a 'beep' each time the PTT button is released. Comes as a full form kit with all components, PCB, die-case box and front panel label. rl s3995 CatK-6002 Ifs Back! QQQ FAN SPEED CONTROLLER Warmer weather is fast approaching, so while you 're thinking about dusting off the old fan you might like to make it more effective by building this Fan Speed Controller. It's easy to build and comes as a full form kit with PCB, all components, plastic case with pre-punched & silk screened front panel, plug and socket and a plastic pot so there's maximum insulation for By popular demand! Technicians, antenna installers, anyone who deals with FM/TV antenna installations will find this kit invaluable. This Field Strength Meter is the easy way to solve antenna position problems. It's battery operated (with charging circuit) or it can be powered by an external DC source (9 - 14V). You can even use it to convert a video monitor into a TV set. Full form kit comes with all components, PCB, case and pre-punched, silk screened front panel. Battery not included. -<at> 8/88 s199 ~~td:-~:B~ety. QUAD 'DI' BOX s39>5 Q Added Insulation for Extra Safely! TV FIELD STRENGTH METER Cat K-6329 <at> 9, 91 Ii rZ1 Mains - -<at>7 /91$39'15 Kits marked with this symbol involve mains power wiring. L_ZJ Take extreme care when workinp with this equipment. Q QQ QQQ Degree Of Simplicity Simple Intermediate Detailed QQ ----·----~ At last, a practical solution to the problems confronting stage and studio _ _ __ _ _ _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ __ performers needing to connect several devices to a mixing box! This mains powered (requires M-9527 plug pack) Quad 'DI' box kit has significant advantages over battery powered versions and will replace up to four separate direct injection (DI) boxes ... at a fraction of the cost. It's easy to build and comes with all components, PCB, case and silk screened & pre-punched front and pre-punched rear panels. , Cat K-5012 <at>6/91 s7995 B1197/ M1 SERV . b alittleeasier. ake , ,ourJO •·· To m :::, .~ ( Bargain Priced! r1ITT. TT'"~IT·~TT.2IT:~~r~,cls·;~· ~·~m-~ ~mm. m 25 PIECE ALLEN KEY SET HOBBY'G' CLAMP SET Three handy 'G' clamps that are perfect for most hobby work, model making, etc. All fit the 30mm (diam.) magnetic base supplied. Sizes include 40mm x 35mm, 30mm x 30mm & 20mm x 25mm. $595 CatT-4755 Cat T-1380 This set is a must for any toolbox. It contains a superb range of Allen Keys in both metric and imperal sizes to suit most applications. Short-arm Metric key sizes range from 1.5mm to 10mm while the long-arm Imperial keys range from '!,•"to¾" in size. All 25 pieces are stored in a handy plastic wallet. Cat T-SOSS ifg~i~~ENCIL It's incredibly convenient and ideal for heatsink work, silver solder, gold, silver, brazing, glass work, etc. The Butane Pencil Blowtorch fits easily in the pocket (it's not much bigger than a pen)and it's powered by butane gas (the same as they use in cigarette lighters, etc). A great idea for site-work and it's super value as well! Value Plus! $C)95 HOBBY'F' CLAMP SET Just like a spare set of hands for the workbench or toolbox. Three sizes: 20 x 120mm. 20 x 80mm & 20 x 40mm. All three clamps fit to the 38mm magnetic base included in pack. $ Electronic Ignition! BLOW-TORCH WITH STAND It's new! This high power blow-torch has a fully adjustable flame so you get just the right amount of heat.... where you want it. The build quality is exceptionally high and it comes with a handy stand which allows you to keep both hands free while you get on with the job. CatT-1390 595 CatT-4750 ■ ELECTROLUBE■ I SERVICE AIDS Safe And Effective! I PCB CLEANER To remove contamination from PCBs before soldering and remove flux residue afterwards. Handy also as a degreaser. 500g spray. S1C)95 Cat N-1105 Special Introductory Offer! ELE<;TRONIC CLEANING SOLVENT Now's the time to stock up on cleaning solvent with this great introductory offer! For this month only you can pick up a huge 400ml can of cleaning solvent at a price that's too good to pass up. This fast acting solvent is suitable for cleaning live components, leaves no residue and is non-corrosive. $11.95 200ml Spray. Cat N-1100 Introductory Special! 400ml Cat N-1165 ONIY $19.95 AIR DUSTER The ideal way to clean inaccessible or . delicate parts .... with high pressure gas. Includes pressure control valve. 400ml spray. CONTACT CLEANER LUBRICANT Improves electrical contact, suppresses arcing, cleans and lubricates contacts to help reduce wear. fantastic for keeping pots clean and silent. 300g spray. CatN-1115 SPRAY FREEZER Non-corrosive refrigerant for rapidly cooling small components in live circuits. The ideal way to detect faulty solder joints and overheated components. 450g spray. Cat N-1110 S249!i TAPE HEAD CLEANER An efficient cleaner for magnetic tape heads in audio, video and computer equipment. Will not harm plastic or rubber. 150g spray. Cat N-1155 SC)95 S2 795 CLEAR PERMAGARD PROTECTM LACQUER A penetrating lubricant which displaces Cat N-1150 moisture. Use it to protect tools and components from corrosion, free seized parts and minimize wear. 200ml spray. Cat N-1120 s1095 A protective coating for printed circuit boards to keep-out harmful salts and moisture. Coating can be soldered through . 200ml spray. Cat N-1130 $1495 HEAT TRANSFER COMPOUND NICKEL SCREENING COMPOUND For efficient and reliable thermo coupling of electronic components and heatsinks. 22g syringe. $89!1 Cat N-1200 Protects both plastic and metal components from RF interference. High attenuation level across a wide frequency range. 450g spray . Cat N-1135 $4495 Red Hot Price! SUPER VGA GRAPHICS ADAPTOR More colours, higher resolution and faster screen loading! This super fast, Super VGA adaptor will bring that boring old computer display to life. With an incredible 256 colours and an astounding 1024 x 768 pixels resolution (that's sharp!).... or perhaps 768 x 1024 pixels resolution for when you're working on Desktop Publishing applications, etc. This has to be one of the best value Super VGA graphics adaptors available. It's easy to fit to just about any IBM compatible (XT or AT) and, it comes with a huge 1Mb RAM on board! Just look at these features ..... • • • • • • • • Super Fast 1Mb of DRAM 16-Bit (can also be used on XT's) Video modes compatible with all standard IBM modes Plus Super VGA! Up to 1024 x 768 pixels in 256 COLOURS 7 Selectable display modes Text modes include .... 80 column 25, 30, 43 & 60 rows 132 column 25, 30, 43 & 60 rows • Comes with drivers for a huge range of the most popular software! Want The Best Computer Display? VGA COLOUR MONITOR When you're working, or playing, on your computer, the monitor is the vital link .... why would you settle for anything but the best? This superb Digitor 30cm VGA Multisync Colour Monitor is capable of displaying VGA and Super VGA screens in 256 vivid colours! It's beautifully designed with controls conveniently located on the front of the monitor and a swivel base which gives you the freedom to adjust the monitor for the best, most comfortable viewing angle possible. And it comes complete with cable to suit IBM compatibles. Cat X-2414 A Fantastic Buy! $499 MONITOR EXTENSION CABLE Like to put your screen on the desk and away from your CPU? This bargain priced monitor extension cable makes it possible. It looks incredible! Just imagine what it would be like to see an image on your computer screen that was so sharp, so clear, so finely detailed that it looked just like a photograph .. . with the Super VGA adaptor, that's just what you can get. Cat X-2603 CatX-2001 You'll find a full range of ready made computer cables available at your nearest store. Outstanding Value! Some stock lines may not be available at all stores . YES! Just $C)95 DS XPRESS PHONE & MAILORDER SERVICE Outside Sydney (FREE Call) 008 22 6610 Sydney And Enquiries - 888 2105 FAX: (02) 805 1986 or write to DS XPRESS, PO BOX 321 N/RYDE NSW 2113 All Major Credit Cards Accepted. O/Nite Courier Available. 24 HOUR DESPATCH OF ALL ORDERS PHONES SECURITY AUDIO COMPUTERS NSW • Albury 21 8399 • Bankstown Sq uare 707 4888 • Blacktown 671 7722 • Brookvale 905 0441 • Bondi 387 ·1444 • Campbelltown 27 2199 • Chatswood Chase 4111955 • Chullora 642 8922 • Gore Hill 439 5311 • Gosford 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 66 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 328 8086 & 246 Bourke St 639 0398 • Richmond 4281814 • Ringwood 879 5338 • Springvale 547 0522 QLD • Brisbane City 229 9377 •Buranda 391 8233 • 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 3471900 • Elizabeth 255 8099 • Enfield 260 8086 • St. Marys 277 8977 WA • Cannington 451 8886 • Fremantle 335 9733 • Perth City 481 3281 • Midland 250 1480 • North bridge 328 8944 TAS • Hobart 31 0800 NT• Stuart Park 811977 ORDER BY PHONE OUTSIDE SYDNEY (008) 226810 FREE CALL - SYDNEY AREA 888 2105 YOUR EIGHT SPECIALTY STORES IN ONE DICK SMITH (WHOLESALE) PTY LTD ACN 000 908 716 81197/PB Road testing the HP54601A 100MHz oscilloscope In the April 1991 issue, we previewed the new Hewlett-Packard 54600 series 100MHz oscilloscopes. We were quite impressed but first impressions are not enough to judge a new product like this. So now we present a more detailed review. By LEO SIMPSON Flying to Melbourne to see the latest oscilloscope from HP is all very well but to really come to grips with an instrument like this you need to spend many hours with it on the bench, using it in a wide variety of situations. It is only then that you can make a realistic assessment. Having had a model 54601A 4 channel unit on trial for a couple of weeks we can now present some conclusions. First, it is, as we thought, a dramatic improvement on all previous digital sampling scopes. Second, it is easier to use than just about any equivalent analog oscilloscope, with or without CRT readout. And third, it is the first of a new generation of oscilloscopes which will eventually make all but the most basic analog scopes obsolete and uneconomic. Having said all that, there are some applications where the analog oscilloscope still does a better job - we'll mention those later. First impressions of the 54601A are that it is compact, relatively light and essentially not much different from an analog scope apart from its large screen and buttons below the screen. Not including the handle and accessory case on top, it measures 317mm wide , 175mm high and 305mm deep. Weight is 6.4kg. The all plastic handle makes it very easy and comfortable to carry and it can be set up as a tilting bail. One clue that this is not a normal scope is the size of the screen which is quite large at about 130mm wide and 105mm deep. Active display area, not counting the space taken up by alphanumeric information at the top and bottom of the screen, is about 125 x 83mm. ' Compare that with a typical scope with a 105mm by 85mm screen (ie, 10 x 8cm) and an overall case depth of over 40cm. With the larger screen, you'd expect the HP unit to have a depth of about 50cm. The reason why it doesn't is that the HP does not use a This is the split screen mode for the HP 54601A. The upper trace runs with the normal timebase (tµs/div) while the lower trace is the delayed timebase (10ns/div). In this case, the pulse rise time is shown as 29.47 nanoseconds. 8 SILICON CHIP This waveform shows that the 54601A can display waveforms which are ostensibly well above its useable bandwidth. In this case, the signal is around 184MHz. Note that the display is clean (apart from the dots), bright and well spread out with a timebase setting of 2ns/div. On most analog scopes with equivalent bandwidth, this waveform would be impossible. At the high end, it runs to 2ns/div (10 times faster) while at the low end it creeps across at 5 seconds/division (25 times slower). At the very lowest speed, it takes 50 seconds for a waveform to be retraced across the screen. That's really slow but it gives an absolutely steady waveform, as you would expect from a raster scanned display. There is another big advantage from using a video monitor style tube and that comes about in terms of cost, life and reliability. Conventional analog scope tubes are very costly, especially those with PDA (post deflection acceleration) and they require expensive mu-metal shielding. Worse still, they may only last a few thousand hours before needing to be replaced. Against that, a cheap and readily available video monitor tube stacks up pretty well. Quiet fan While relatively unimportant when related to the high technology in this unit, we must comment on the fan - it is quiet. This is a nice change from the fans on many oscilloscopes (and computers) which are often tiny units which make an unseemly racket. Another nice feature is the soft vinyl bag on top of the unit for storage of accessories such as the probes. While HP and other upmarket scopes have had this as a feature for quite a few years, it is worth noting that it is very convenient. It certainly helps stop probes and the user manual from going missing. Driving it Amplitude modulated waveforms are easily displayed on the 54601A. This display shows a waveform with a frequency of about 65MHz and 400Hz modulation. normal scope tube. Instead, its tube is exactly the same as would be found in a small green screen computer monitor. It is not vector scanned like a scope (ie, with the waveforms exactly traced out by the electron beam) but is raster scanned like a conventional TV or computer video monitor. This means that the display is made up of very fine dots, (500 x 255 pixels). Because the 54601A has a raster scanned display, the trace or traces (up to four) are always constant in brightness. By contrast, in a conven- tional scope, the beam has to "write" at a faster and faster speed as the timebase is switched up (maximum, around 20 nanoseconds/div). So for high frequencies and very fast pulses, the trace brightness becomes very faint and difficult to see. At low timebase speeds, the traces become very flickery, until at the lowest speeds (0.2 seconds/div), the trace flares badly as it becomes a bright dot moving very slowly across the screen. With the 54600 series, the range of timebase speeds is a great deal wider. We've already noted in our April preview of this scope that it is easy to drive and having now spent a few weeks with it we can emphasise that point. But reading through the manual and then using the recommended procedures therein shows just how well thought out it is. Consider, for example , how you can make time (frequency, etc) and voltage measurements off the screen of an ordinary scope, provided the variable vertical gain and timebase controls are in their "calibrate" positions. Once you start using these vernier controls to get a better look at a waveform though, you don't know what your voltage and timebase settings are. On the 54600 series units you can engage a vernier facility for both the vertical sensitivity and timebase, via OCTOBER 1991 9 This is the sort of waveform you can expect when you push the 54601A right to the limit of its sensitivity. Here it is running at 2mV/div and there is really not enough signal for it to work properly in the Normal display mode. Selecting an "Average" display mode cleans up the signal but it then responds to changes much more slowly. Frequency and period measurements are a snack with the 54601A. This waveform was fed in, displayed using Autoscale, the Time button pressed and then the Freq, Period and Duty Cy softkeys pressed to display the readings at the bottom of the screen. one of the softkeys immediately below the screen. The difference here is that not only is the exact sensitivity and timebase setting displayed (eg , 4.76V/div, 184µs/div) on screen but automatic and manual measurements are still available. Some of the automatic measurements possible are illustrated in the photos. The "Autoscale" facility is a very worthwhile feature .You just feed in a signal, press the Autoscale button and the scope computes the optimum set10 SILICON CHIP tings (some upmarket analog scopes also have this feature). There are some conditions under which the facility won't work: frequencies below 50Hz; pulse waveforms with a duty cycle of less than 1 %; and signals with an amplitude of less than about l00mV RMS, depending on frequency. For those conditions, pressing Autoscale will bring up an on-screen message saying "No signal found" even though, in some cases, the display will appear on screen! There are some traps involving Autoscale too . Say you want to view a small signal on Channel 1 and you are feeding a sync signal into Channel 4. You can set up the display manually and get a stationary waveform but if you then accidentally press Autoscale the scope will pick Channel 4, the stronger signal, as the one to be displayed. Even then, after momentarily kicking yourself, the situation is easily fixed. Just press the Setup button, to bring up a new Softkey menu and then press "Autoscale Undo". This reverts the scope to your previous settings. You can also save your screen setup and there are two trace memories which can be recalled at any time so that you can compare a previous waveform (displayed at half brightness) with those presently on the screen. Rise and fall times Making rise and fall time measurements with a conventional delayed timebase scope can be very tricky but with this HP unit, dare we say it, it is dead easy. With a signal being fed in, you push the Main/Delayed button, select Delayed timebase operation and you immediately get a split screen display. You can see this in one of the photos. At the top is the waveform · being measured while below is the expanded/delayed timebase display. For a quick measurement of rise and fall times, you need only press a few buttons. Push the Time button and it brings up the "Time Measurements" menu on the bottom of the screen (for Frequency, Period and Duty Cycle). Press the "Next Menu" button and it brings up RiseTime, FallTime etc. You can then get a reading for both rise and fall time by just pressing the two buttons required but if the times are very short (ie, in nanoseconds). then you have to go a bit further. At the top right hand corner of the screen, is the legend RUN, STORE or STOP, depending on the Storage mode in use. To the left of that is a legend showing which channel is the trigger source and what is the trigger slope; normally positive. For measuring rise time, it is best to use the positive slope which then shows the pulse rising edge on the delayed screen. To measure the fall time, you need to display the trailing edge on the delayed screen. This is easily done by ELECTRONIC WORLD Riston negative acting precoated circuit board Single Double sided sided 76mm x 127mm $2.60 $ 3.25 100mm x 160mm $5.70 $ 7.20 127mm x 152mm $5.70 $ 7.20 152mm x 254mm $10.70 $12.95 254mm x 304mm $20.50 $24.80 Instructions supplied with PCB This photo shows how easy waveform voltage measurements are with the HP54601A. It's all done by simply pressing a few buttons. pushing the Slope/Coupling button which then allows you to select positive or negative slope triggering. To get the most accurate figure, you need to run the delayed timebase so that the expanded wavefront (or trailing edge) spreads over a couple of divisions or more. Then, if you press for positive slope coupling, you'll get an accurate figure for the rise time and an approximate figure for the fall time, expressed symbolically as less than or equal to, say, lO0ns. Then, as you select for negative slope coupling, you get an accurate figure for fall time and an approximate figure for the rise time. All these measurements and a great many more besides, are much easier and quicker to run through on the scope than they are to describe in this text. By now then, you should have the idea that the 54600 series machines are particularly ' well thought out and easy to use. As an indicator of that, all the photos accompanying this article were taken before we had a chance to familiarise ourselves with the user manual; we weren't using the instrument to the best of its capabilities at that stage! Special situations At the start of this review, we mentioned that analog scopes could still do a better job in certain applications and there are at least two that we canthink of. First, where you need absolute waveform fidelity on the screen, the dot waveform structure of the HP is something of a drawback. In most cases though, this probably does not apply and the 54600 display will be entirely adequate. It is very good at picking up very fast glitches in wavetrains and better than normal scopes where you generally have to focus very carefully and then use a viewing hood in order to avoid missing very faint transients. A second situation entails low signal levels, say below 50mV peak to peak. Here there is really not enough signal for the digital to analog converter to process properly and the resulting display is only approximate and made up of a series of very short horizontal lines rather than dots. You can improve this situation by changing the Display mode to Average rather than Normal. This averages the display over a number of sweeps which may be selected at 8, 64 or 256. This changes the display back to a dot structure but now it is slow to update and very slow if you pick the 256 average. Interestingly, even here the 54600 does pretty well because even though it may not show a really good waveform (and that can be a real drawback in some measurement situations), its own noise level is generally better than typical analog scopes and so there is less noise on the screen. Well, as you've guessed by now, we're pretty impressed and we think that this is the precursor of all future oscilloscopes. The fact that it costs less than equivalent analog scopes is a sure indicator of that. SC Riston PCB developer $3.00 Riston PCB stripper $2.50 Reversing film (if required} 250mm x 300mm $8.10 Positive resist spray Positive developer $34.95 $15.95 Giant 3-inch ?-segment red display common cathode $25.50 8mm ?-segment green display common cathode $1 .25 Toggle Qty: 1-9 250V/10A 10-49 SPST switch 50+ $1.25ea $1.00ea $0.95ea 12VDC to 240VAC 40W Inverter Kit form K6705 $99.00 12VDC to 240VAC 300W Inverter Kit form K7659 $279.00 Built & tested K6755 $379.00 12/24VDC to 240VAC 600W Inverter Kit K6770 $499.00 Built & tested $625.00 Specify DC voltage required Commercial heavy duty units 12V/240 200W SP1200 $429 .00 12V/240 480W SP1480 $749.00 12V/240 650W Magnum $899.00 12VDC to 240VAC 300W Inverter Sinewave Output $835.00 Larger inverters to 1200W available on request. Mail orders and retail sales: Electronic World, 30 Lacey St, Croydon Vic. 3136. Telephone: (03) 723 3860 (03) 723 3094 Fax: (03) 725 9443 Disposals bargain store at: 27 The Mall, South Croydon, Vic 3136 Telephone: (03) 723 2699 OCT0BER1991 11 Check your exposure to power line fields with this Magnetic field st, Are you concerned about the 50Hz magnetic fields in your home and workplace? By building this low-cost Digital Magnetic Field Meter you can accurately measure these fields and then take steps to minimise any possible effect they may have on you and your family. Appliance <100mm distance 300mm distance 1kW radiator 2.5uT .04uT 60W light bulb 0.3uT 0.15uT TV set 2.0uT 0.3uT Computer monitor 0.2uT .02uT Stove element 200uT 10uT Hair dryer 30uT 1.5uT Electric shaver 1.5mT Fluorescent desk lamp 250uT 0.2uT Lov voltage desk lamp 250uT 0.2uT Food mixer 0.3mT 5uT Vacuum cleaner 250uT 10uT Electric drill 200uT 8uT endocrine and nervous system disorders, including chronic depression, are also under investigation. Placing these health concerns into a proper perspective, the effects of 50Hz magnetic fields are not in the same league as those caused by Xradiation, nuclear radiation, vehicle accidents and chemical toxins. These are extremely well documented while the health effects of 50Hz magnetic fields are only just beginning to be researched. It appears that magnetic fields may be "cancer promoters" rather than a direct cancer source. That is to say, if a person if exposed to a set of circumstances which cause cancers, the risk will be increased slightly if the person is also exposed to low level magnetic fields. The increased risk is assumed to be proportional to the strength of the 50Hz (or 60Hz) magnetic field, as well as the overall time of exposure. With an electric blanket for instance, although it produces a very low field, the fact that a person may sleep on it for many hundreds of hours each year while it is energised suggests that it might be associated with increased risk. Just how much exposure is considered safe is open to debate. The International Radiation Protection Association has issued interim standards based on research to date. They set an upper level of 100 micro Teslas (µT) for the general public. For exposure in the workplace, the level is higher at 5D0µT over the entire working day. However, other research has indicated that exposures to fields as low as 0.25µT have some correlation with an increase in cancer rates. Circular saw 150uT 15uT Field sources 1A plug pack transformer 300uT 3uT There are various sources of magnetic fields to be found in the home Ever since the advent of electric power, people have been increasingly exposed to 50Hz or 60Hz electric and magnetic fields produced by the power lines and related equipment. Up until recently, there has been little concern about this but in the last few years, people have become very concerned. Why? Partly because people are now more concerned about the environment but more importantly because low level magnetic fields have been shown to have an effect on living organisms. In particular, it has been suggested that there are links between low level magnetic fields and an increased incidence ofleukaemia, lymph tumours, brain tumours and birth defects. Links between 50Hz magnetic fields and Table 1 12 SILICON CHIP - 2uT By JOHN CLARKE ength meter environment, the most obvious being power lines. In particular, your home could be located near to high-voltage transmission lines or distribution transformers. Inside the home, just about every electrical appliance is a source of magnetic fields. The amount of radiation and exposure depends upon the actual appliance and the type of use. Table 1 lists some typical magnetic field readings of some household appliances, measured with our Magnetic Field Meter. So what can be done to reduce exposure to these sources of radiation? The first thing to do is to use the Magnetic Field Meter to measure the field strengths about the house when appliances are on. In particular, check on places where people spend a long period of time such as in the bedroom and lounge room. If the radiation is high, you may well be able to rearrange the layout of the room to minimise exposure. The Magnetic Field Meter is capable of measuring magnetic fields from 0-20mT over three ranges. Using the meter is simple: you just switch it on, move it close to the source to be measured & select the appropriate range. The reading is displayed directly on a 3½-digit LCD. Magnetic field meter Our Magnetic Field Meter is housed in a plastic case measuring 95 x 45 x 145mm. It has a 3½-digit liquid crystal display (LCD) which indicates the magnetic field strength in micro Teslas or milli Teslas (µT or mT). A 3-position rotary switch selects the ranges which are 2µT, 200µT and 20mT. A push-on/push-off switch is used as the On/Off switch while a momentary contact pushbutton checks the battery condition by lighting a LED. If the LED glows brightly, the battery is OK. To use the meter, all you need to do is switch it on, bring it close to the radiation source and select the best range. You should also adjust the orientation of the meter to get the highest reading. As you move the meter away from the source, the radiation level will drop off at a rate determined by the type of appliance or source of radiation. Some sources will have a fast drop off while others will drop off only slowly. Circuit details The circuit of our Magnetic Field Meter uses a pickup coil to sense the magnetic field. This is followed by an amplifier (IC1), a precision rectifier (IC2) to change the AC signal to a DC level, and a digital voltmeter involving IC4 and the liquid crystal display. The three ranges are provided by 4pole rotary switch S3. You will find these four poles in different parts of the circuit but they all operate together, to vary the amplifier gain (S3a & S3b), shift a reference voltage (S3d) and switch the decimal point (S3c) of the liquid crystal display. IC1 is an LM324 quad op amp package which is used for the amplifier stages. The signal picked up by Ll is coupled via a 4. 7µF capacitor to IClc which functions as an inverting amplifier with a gain of 3.3. Signals above lkHz are attenuated by the .0047µF capacitor in parallel with the 33k0 feedback resistor. The output ofIClc feeds IClb via a 4.7µF capacitor and passive RC network comprising a 10k0 resistor and .033µF capacitor to attenuate signals above 500Hz. IClb functions as anoninverting amplifier. Its gain is set by the 4 70k0 feedback resistor and the resistors switched by S3a. When S3a is in positions 1 & 2, the gain is set to 100 while for position 3, the gain is unity. OCT0BER1991 13 PARTS LIST 1 plastic case, 95 x 45 x 145mm, DSE H-2503 1 PC board, code SC04211911, 75 x88mm 1 PC board, code SC04211912, 89 x43mm 1 front panel label, 88 x 42mm 1 3½-digit liquid crystal display, 50 x 31mm, Farnell Cat. H1331CC or equivalent 2 20-way wirewrap pin headers 1 9V battery holder, DSE S-6150 or equivalent 1 216 9V alkaline battery 1 SPOT push-on/push-off switch 1 SP momentary push-on switch 1 PCB mount 4-pole 3-way rotary switch 1 knob with pointer 1 50cm length of 12-way ribbon cable 1 50cm length of 0.5mm enamelled copper wire 1 50cm length of 0.8mm tinned copper wire 6 PC stakes 4 3.5mm screws and nuts 4 small adhesive rubber feet 1 20kQ miniature horizontal trimpot (VR1) 1 1O0Q miniature horizontal trimpot (VR2) Semiconductors 1 LM324 quad op amp (IC1) 1 OP77GP low offset op amp (IC2) 1 4030/4070 quad EXOR gate (IC3) 1 l<i;L7106CPL AID converter & LCD driver (IC4) 1 4.7V 400mW zener diode (ZD1) 1 3mm LED (LED1) 2 1 N4148 signal diodes (D 1,D2) Capacitors 1 100µF 16VW PC electrolytic 1 47µF 16VW PC electrolytic 3 10µF 16VW PC electrolytics 3 4.7µF 16VW PC electrolytics 2 0.22µF metallised polyester (5mm lead spacing) 4 0.1 µF metallised polyester (5mm lead spacing) 2 .033µF metallised polyester (5mm lead spacing) 1 .0068µF metallised polyester (5mm lead spacing) 1 .0047µF metallised polyester (5mm lead spacing) 2 470pF ceramic 1 100pF ceramic Resistors (1 %, 0.25W) 1 1 MQ 2 470kQ 1 220kQ 5 100kQ 1 82kQ 1 33kQ 1 22kQ 7 10kQ 1 8.2kQ 2 4.7kQ 1 2.2kQ 21kQ 1 330Q 2 47Q Fig.1: the circuit diagram for the Magnetic Field Meter. The magnetic field is picked up by coil Ll, amplified by IClc, IClb & ICla, & precision rectified by IC2 & D1. The output from the precision rectifier then feeds AID converter IC4 which then drives the 3½-digit LCD. The output signal from ICla is coupled to the rectifier circuit via a 47µF capacitor. The combination of the 47µF capacitor and the lkQ resistor provides a low frequency rolloff of 3.3Hz to further reduce noise from the amplifier stages. The rectifier works as follows. When the signal goes positive, pin 6 of IC2 goes negative since it is connected as an inverting amplifier. This reverse biases diode D1 and so the output at pin 6 is effectively disconnected from the signal path. The positive signal therefore passes through the two 10kQ resistors to the output, at the cathode of D1, without attenuation (there being very little loading by the following circuitry). When the signal to the rectifier goes negative, pin 6 of IC2 goes positive and diode D1 is forward biased. IC2 then acts as an inverting amplifier with a gain of -1. Therefore, both halves of the input signal appear at the output (at the cathode of D1) in fully rectified form. 4V reference Following IClb is an identical amplifier stage consisting of IC la and its associated components. In this case, the gain is set by switch section S3b. When S3b is in position 1 (2µT), the gain of ICla is 100 while for the other two positions , the gain is unity. The 4. 7µF input coupling capacitor to each stage (IClc, IClb & ICla) rolls off the response below 3Hz. In addition , when IClb & ICla are switched to provide a gain of 100, their response is rolled off above 700Hz by a 470pF capacitor in parallel with the 470kQ feedback resistor. At the same time, their response is furth er rolled off below 3Hz by the 10µF capacitors associated with S3a and S3b. In combination, IClc, IClb & ICla are capable of providing a great deal of gain. When set to the 20mT range, 14 SILICON CHIP the gain is just 3.3, as set by IClc. For the 200µT range , the gain is 330, as provided by IClc & IClb. Finally, for the ZµT range , all three amplifiers provide a total gain of 33,000. This gain only applies for those frequencies between about 10Hz and 500Hz, to minimise noise pickup as much as possible. Precision rectifier Following the amplifier stages is a precision full wave rectifier. This is based on IC2 , an OP77GP manufactured by PMI. This is a very high quality operational amplifier with very low offset voltage and exceptional gain linearity. It is ideal for use as a precision rectifier and uses only three other components: two 10kQ resistors and diode D1. The three amplifier stages and the precision rectifier involving ICZ are all biased from . a 4V rail which is provided by ICld. ICld is connected as a unity gain buffer and is fed with +4V from a voltage divider consisting of a l00kQ and 82kQ resistors. The next stage in the signal chain is the analog to digital (AID) converter and 3½-digit display driver, IC4. This is an ICL7106 chip made by Intersil and used in many digital multimeters. IC4 measures and displays the voltage qifference between its INHI and INLOW inputs. The output from precision rectifier IC2 is applied to the INHI input of IC4 at pin 31 via a filter consisting of a lMQ resistor and the 0. lµF capacitor (connected between the INHI input and the common input). The INLOW input, pin 30, is connected to the 4V reference supply via switch S3d. .0047 -- ■■ 33k 10k 1% .... 1Qk 470pF 8.2k .033: 470k = 1k .... PRECISION FULL WAVE RECTIFIER 470pF 4.7k 1% 4.7k 1% -2uT 10 16VW 47~~ 1% ---·.. - s3a 47n~ 1% ~ 10 16VW -- -■■• 020mT JuT _ S3b 0200uT 020mT --------------r-""""1r----f---•9v 22k 2.2k 1M VR1 20k 1k ~ VR2 100n ~ 31 2UT- ► -----------------7 ------------------7 5 A1~ 4 B1ag REF HI 3 C1~~ - - - - - - - - - - - - - - - - , D12 35 REF LOW TP202 I ~ 1N4148 ,;: L vcc 8 E11-2- - - - - - - - - - - - - - , 6 F11-2- - - - - - - - - - - - - , 7 G11! A2 12 IN HI 3o IN LOW r::T - S3d 0.1:: -------------7 0.1:~ 32 ' - - - - - - - . - -'1 COMMON 82 +4V D21l!9' - - - - - - - - - - , E2 14 IC4 ICL7106CPL 0.1 33 ' - - - -"1 REF CAP 40 - - - --1osc1 100k F213 62 25 A3t=2_,._3_ _ _..., lso ::: ~~ ·I i--, LCi--, F/~) 8 OSC3 ' - - - -3"1 29 ....-----tAUTO ZERO ... 0.22: POWER S1 I I :.L T 9V ..l... I 1 .,- BATTERY11l TEST II J S2 -- I~~ 4.7V j"! ZD1 400mW 3 '• / DP2 '• e/ 01 DP1 2 DP3 DP1 16 /c 1 BPr- DP2 12 +9V---t---, l I~ M 100J;16VW+ 100k •4V 82k K = +9V '°).. 3300 K/ DP3 • / K'~1"':l K 9_ _ _ -!;6 l~AB LED1 l: : :; : 2i BUFFER 27 ~ - - --tlNT BP TEST GND 21 37 I I I 21 1,~ 13 14 115 ?4 25 is 122 11 1s 19 20- 21 A3 G2 F2 E2 DZ C2 82 AZ 61 F1 E1 01 C1 81 A1 39 OSC2 100pF== 220k 11 cz 10 _ _ _...,34-'IREF CAP .,. 01f IC3a 121:"--,. 4 r~ 2· 4030 4070 14 - J; 10 16VW? +4V t-4 IC3b 6' 4 e~10 9- 7 ~B11- -~ - S3c - 20mT 100k I 100k 100k BIAS VOLTAGE MAGNETIC FIELD METER OCT0BER1991 15 ------65mm------ r 1 ! 11 " , "'· ,.~. '"' '""'""" "'"" ~I Fig.2: here's how to install the parts on the main PC board. The pickup coil (L1) is made by winding it around the outside of the fully-assembled case & then moulding it to the required dimensions. 1i1 1 :11 L Because ICZ is also biased from the 4V reference , its output will normally sit at +4 V, with no signal being picked up by coil Ll. Thus, there will be no difference between the INHI and INLOW inputs and the display will show zero. At other times, when signal is present, the INHI input will be above 4V and a positive value will be shown on the display. Noise cancelling Because the amplifier stages provide so much gain (x33,000) on the most sensitive range, there is some noise present in the signal applied to the INHI input and normally this would cause the display to jitter quite a bit. To reduce this effect, an offset voltage is applied via trimpot VRZ to the INLOW input when S3 is set to the most sensitive range (ie , the ZµT range). The offset voltage for VRZ comes from diode DZ which is supplied via a 2.ZkQ resistor from the 9V rail. This diode gives a stable reference which is 0.6V above the +4V rail. The voltage from DZ is then fed to VRZ via a lkQ resistor. 11 1 - J The liquid crystal display is not multiplexed which means that there is a connecting line from the display to IC4 for every segment to be energised. Liquid crystal displays are energised by an AC voltage. Hence, there is a backplane (BP) square wave signal of 5V and each segment is turned on by applying an equal but complementary (inverted) 5V square wave. So that's what IC4 does when driving the display. IC3 is used to drive the decimal points. It is connected to produce a signal complementary to the backplane signal. This complementary signal is applied via S3c which feeds it to one of three decimal points, according the range selected. Battery test Power for the circuit comes from a 9V battery, as already noted. Switch Sl is the On/Off switch and the supply is decoupled with a lO0µF capacitor. A simple battery test feature is included in the circuit. This comprises pushbutton switch SZ, LED 1, a 330Q resistor and a 4. 7V zener diode , ZDl. When SZ is pressed, the LED lights if the battery is OK. Since the LED requires about 1.8V across it to light and the zener diode requires 4.7V across it to allow current to pass, it follows that the battery must be able to deliver about 8V in order to light the LED reasonably brightly. As a final note on the circuit, to avoid the need for a complicated calibration procedure, we have specified 1 % resistors throughout. Of course, not all the resistors really need to be 1 % but to avoid confusion, we have made them all the same. Construction The Magnetic Field Meter is constructed in a standard plastic case measuring 95 x 45 x 145mm. This case has two halves which ·clip together - no screws are required. The circuitry is carried on two PC boards: a main board coded SC04Z11911 and measuring 75 x 88mm, and a display board coded SC0421191Z and measuring 89 x 43mm. Inside the two halves of the plastic case are a number of integral pillars and reinforcing webs. Some of these PCB ] " TI LC NUT ·s1 -'-~ i' 2120-WAY FOR MOUNTING LCD Fig.3: take care to ensure that there are no shorts between adjacent links on the display PC hoard (use insulated wire if necessary). 16 SILICON CHIP ~STAR WASHER NUT Fig.4: this plan view shows how the display board is secured to the front panel using the switch nuts. The LCD mounts in two 20-way wirewrap socket strips. CAPACITOR CODES □ □ □ □ □ □ □ □ Value 0.22µF 0.1µF .033µF .0068µF .0047µF 470pF 100pF IEC Code 220n 100n 33n 6n8 4n7 470p 100p EIA Code 224 104 333 682 472 471 101 must be removed from the base before the boards can be installed. You can do this using a utility knife or sharp chisel. That done, you can begin assembly of the main PC board. Fig. 2 shows the wiring details. Start with the PC stakes and low profile components such as the links and resistors , then install the two diodes and the zener, making sure that they go in the right way around. Now the ICs and capacitors can be installed. The ICs must be oriented as shown on the overlay diagram and the electrolytic capacitors must go in with the correct polarity. When all the components are installed, there are seven short ribbon cables to be made up which link it to the display board. These are shown as bus connectors on the board overlay diagram: A, B, C, D, E, F, G and H, but we wired .the cables directly to the boards, without plugs and sockets. The two PC boards are wired together using short lengths ofrainbow cable, as shown here. Be sure to connect the leads in the correct order & solder them directly to the copper pads on the back of the display board. The A and B buses are 7-way, the C bus is 4-way, the D, E, F and H buses are 3-way, and the G bus is 2-way. Make each ribbon cable at least 10cm long. The display PC board requires a fair amount of work, even though there are less components to be installed on it (see Fig.3). First, the corners need to removed so that the PC board fits inside the case. If you have a look at the PC artwork, it will be obvious just how much of each corner has to be removed. There are quite a lot of links to be installed and these must be done before you proceed further. Make sure that the links do not touch each other (or run them with insulated hook-up wire). Next, install the three 10okn resistors. The three front panel switches and the LED are mounted directly on the display board and are eventually secured to the front panel. The mounting detail diagram (Fig.4) shows the relative h eights required. Similarly, the two 20-way wirewrap sockets for the display are soldered in place so that when the LCD is plugged in, it RESISTOR COLOUR CODES □ □ □ □ □ □ □ □ □ □ □ □ □ □ □ No 1 2 1 5 1 7 2 2 2 Value 1Mn 470kn 220kn 100kn 82kQ 33kn 22kn 10kn 8.2kn 4.7kn 2.2kn 1 kn 33on 47n 4-Band Code (1%) 5-Band Code (1%) brown black green brown yellow violet yellow brown red red yellow brown brown black yellow brown grey red orange brown orange orange orange brown red red orange brown brown black orange brown grey red red brown yellow violet red brown red red red brown brown black red brown orange orange brown brown yellow violet black brown brown black black yellow brown yellow violet black orange brown red red black orange brown brown black black orange brown grey red black red brown orange orange black red brown red red black red brown brown black black red brown grey red black brown yellow violet black brown brown red red black brown brown brown black black _ brown brown orange orange black black brown yellow violet black gold brown OCT0BER1991 17 The pickup coil is secured at each corner by wire loops which pass through holes drilled in four reinforcing webs in the lid of the case. Be sure to shape the coil to the exact dimensions shown in Fig.2, so that the unit is accurately calibrated. Power comes from an internal 9V battery mounted on the rear panel. will be 15mm above the top of the PC board. Once all these parts have been soldered in place, the display can·be installed. Before doing this, you should check its orientation by looking at the digits in some strong light. The correct orientation is with the decimal points at the bottom of the display and with the rotary switch S3 to the right. Front panel The front panel must be drilled and cut out for the switches, LED and display window. This can be done using the front panel artwork as a marking template. The display window cutout is best made by drilling a series of small holes around the inside perimeter, then knocking out the centre piece and filing to shape. 18 SILICON CHIP Once all the holes have been drilled, the adhesive label can be affixed. This is done by firstly cutting it out to the size of the border with a utility knife or sharp scissors. The backing paper is then peeled off and the label stuck down onto the front panel. The switch holes and display cutout can be made with a sharp knife , followed by a reamer and file to clean up the edges. This done, secure the front panel to the display board using the securing nuts of the switches (see Fig.3) . The two boards can now be connected together via the ribbon cables. Make sure that you connect each wire in the right order. Note that the leadouts of each bus connector are shown on the wiring diagram with a "1" designation. Now you are ready to install the two boards in the case but this should be done so that the main board does not interfere with the display board. For that reason, the main board is secured to the base of the case using four machine screws and nuts and located 26mm back from the front of the case. It should then just clear the display board when it is installed. Pickup coil The pickup coil for the circuit is made using 14 turns of 0.5mm enamelled copper wire. To obtain the same dimensions as our coil, we recommend that you put the lid on the case and tightly wind the coil in one layer around its outside. Once the 14 turns have been made, you can slide the wires off the case and secure the completed coil inside the lid of the case. We mounted our coil by drilling a small hole in each reinforcing web of the lid. Stiff wire is then passed through the holes and looped around the coil corners. Once secure, mould the coil so that it is rectangular and to the dimensions shown in the wiring diagram. Strip the enamel from the ends of the coil and solder a 10cm length of hookup wire to each end. Finally, connect the pickup coil to the PC stakes on the main board. The battery holder is mounted on the rear of the case at the lefthand side, so that it clears the components on the main PC board. Use double sided tape or 2mm screws and nuts to do this job. The wiring can then be installed between the battery holder terminals and the main PC board. MAGNETIC FIELD METER + BATT. 1:~ + + ON/OFF ~ + RANGE Testing Before applying power, check your construction thoroaghly to ensure that all components are correctly positioned and that all the wiring is correct. When you are satisfied that everything is OK, set your multimeter to read DC volts cin the Z0V scale and connect the negative lead to the (-) supply PC stake. Now switch on and measure the voltage at pin 4 of IC1, pin 7 of ICZ, pin 14 of IC3 and pin 1 of IC4. These voltages should all be at +9V. If there is no supply at these points, switch off immediately and locate the problem before re-applying power. Now check that the display is functioning. On the lower µT range, the lower two digits should be jittering slightly. The second µT range and the mT range should display either 00.1 or 00.0, assuming of course that the meter is not close to a magnetic field (ifit is, it will show some value). If the display does not function correctly, check your wiring for incorrect connections or shorts. The range switch should shift the decimal point from .000 on the lower µT range to 00.0 for the next µT range, to 0.00 in the mT range. The battery test switch should light the LED when pressed. Since the battery should be in good condition, the LED should light brightly. Adjustments There are two adjustments required to calibrate and set up the Magnetic Field Meter. First, VR1 calibrates the unit by adjusting the reference voltage for IC4. To do this, connect your multimeter between TP1 and TPZ and adjust VR1 until the meter reads 330mV. This sets the full scale for IC4 to 660mV and the meter is now cali- Fig.5: actual size artworks for the front panel & PC boards. brated to read correctly in µT and mT with the 11 pickup coil. The second adjustment involves using VRZ to null out the noise caused by the very high gain on the lowest µT range. To adjust this pot, you need to short out the 11 coil by connecting a length of wire across the coil terminals on the PC board. This will prevent any pickup from the coil from interfering with the adjustment. Now select the lowest µT range and adjust VRZ until the reading is as close to zero as possible. Note that because the noise varies over time, it will not be possible to completely null it out. The best result will probably only null the noise sufficiently to allow the display to show .0 with the last two digits varying. Finally, unsolder the short across 11 and clip the case together. SC OCT0BER1991 19 SERVICEMAN'S LOG Murphy has two bob each way Coincidence, chance, luck, law of probability, Murphy's law - call it what you will, it plays a large part in servicing. Sometimes it helps; sometimes it hinders. And when it hinders it has the potential to make an innocent serviceman look like a rogue. No, it didn't happen this time; but that was mainly because the customer has been dealing with me for nearly 20 years and he does trust me. Had it been a new customer, of the suspicious type, it could well have been a different story. In more detail, the customer is the proprietor of a local motel and the story concerns two colour TV sets from his units. They were identical sets - 48cm HMV Model B4803s - but with quite different faults. When he rang me, he explained 20 SILICON CHIP that the more serious fault was a complete picture failure, although there was still normal sound. The other set was still working but had a pronounced red cast. He suggested I take the more serious one first, since the second one was still usable to some extent. When customers say "no picture" it prompts a series of logical questions. Is there any light on the screen? If so, is it a steady raster or is it just a snowstorm? Provided the customer can give clear answers to these questions, one can usually get a pretty good idea of what it looks like and where, in broad terms, the fault is likely to be. In this case, the customer was able to give a clear answer; it was a steady raster, suggesting that the sync pulses were being processed but that the video was being lost somewhere down the track. But that was about as far as I could go at that stage and so I left it to him to bring the set in. I was familiar with the set in general terms and didn't anticipate any real problems. This model is about 12 years old and although carrying the HMV label, with the doggie on the front, it is actually a Japanese chassis, from JVC. And since I was very familiar with most JVC chassis and had a good stock of manuals, I reckoned it would be straightforward. When it turned up, I found it much as the customer had described; normal sound and a nor- mal raster. The only difference was that I detected a faint image and a few faint blobs of colour, particularly when I subsequently fed in a test card. But there was another effect which the customer hadn't mentioned; the raster on the screen was very bright and the brightness control had virtually no control over it. On the other hand, I noted that adjusting the colour control did have an effect on the brightness - not a very great effect mind you, but it was there. It also had a slight effect on the saturation of such colour blobs as were visible. A strange chassis I pulled the back off and took a closer look at the works. And that was the first setback. I thought I knew most of the JVC chassis but this was a strange one. More to the point, a thorough search through both my HMV and JVC manuals confirmed that I didn't have the correct manual, or even a circuit, for it. Tracking down a circuit diagram was obviously going to take some time and so I rang the customer to explain that there was going to be some delay. And that was the first bit of good news; he had kept the instruction books for each of the sets he had bought and these included a circuit. He had a stack of them and I was welcome to one for keeps. As he put it, they were double Dutch to him and so that problem was solved. He duly delivered one of the books and the relevant portion of the circuit is reproduced here (see Fig.1). On the left is the video sync separator, IC201, and to the right of it the video output transistor, X201, fed from pin 16 of IC201. Next on the right is the matrix/ colour IC, IC302. This delivers the RY, B-Y and G-Y signals from pins 6, 2 and 4 respectively to the CRT board, SU-3033A, at extreme right. Also, pin 16 of this IC takes the colour control voltage from the colour control pot (R13) which is on the control board, SU-4205A, at top right. (As an aside, note that the 7.2V on pins 2, 4 and 6 mysteriously becomes 7.4V on the bases of the blue, red and green output transistors, XlOl, 102 and 103. But contradictions like this are nothing unusual in modern circuits.) I checked the voltage on pin 16 of IC302 and this appeared to be responding normally to any adjustment of the colour control. From there, I moved to the three output transistors on the CRT board and checked the collector voltages. These were significantly lower - by about 20V - than the figures suggested on the circuit and enough to make them suspect. Similarly, the base voltages seemed to be marginally high, as one might expect, although it was difficult to be sure since it doesn't take much change here to upset the collector values. In any case, this all added up to a theory that all three guns were being turned hard on, effectively masking any video that might be present. And that was the next check; the luminance path. This starts at pin 16 of IC201 and goes to the base of the video output transistor, X201. The output appears at the emitter of this stage and is fed to pin 1 on the CRT board and thence to the emitter circuits of the RGB output stages. A voltage check around X201 produced figures very close to those on the circuit; nothing really suspicious there. The CRO also confirmed that there was normal video into and out of this transistor and from there into the emitters of the three output transistors-all of which further supported the idea that it was a hard turn-on problem. So what about the brightness control, R30, on the control board? Basically, this is between the +12V rail and chassis, with the moving arm coming out on pin 1 and connecting to pin 14 of IC201. However, the voltage range that this provides is nothing like 12V. Limiting resistors R31, R32, R33 and R34 restrict the range considerably. But by how much? I had no way of knowing but a measurement on pin 14 indicated from 9.5V to a little over 10V; only about half a volt. This seemed to be rather small but, on the other hand, seemed to tally with the .-.·~~-] - :~ r - ~ Wi I ~ , o :6a : [f ___ f]Oa- ~:'i 0 J ~? ;., ::~ - - l l - -- L-..J--------1-+------H----+--' I ' - - - - --- - - . - - ; , . _ . . . . - - - - l - + - - - - - ~ E: -----, ....__......._.. ug~ ]~ ~~ ,1 g~ ~ -· :~ - : pn-u : ~: f '-Y,••~ -- - -- -- - t - , ~ Fig.1: relevant section of the faulty HMV B4803. IC201 is the video sync separator and drives video output transistor X201 which in turn drives the emitter circuits of the RGB driver transistors (X101, X102 & X103). OCT0BER1991 21 SERVICEMAN'S LOG - CTD 1-\0W M\JC~ WOOL.'0 1\-\~ !V\\SSIJ'S &. l<\t)'S F6--rC-H ?.. -- "" ,,. . 1/ ' the almost unbelievable; two faulty ICs in the one set and both contributing to the same major symptom. See what I mean by Murphy having two bob each way! Of course, the prognosis still had to be confirmed. So another IC was ordered, delivered and fitted. And that really fixed everything. The set was given a routine grey scale adjustment, a soak test for a day or so and returned to the customer. And that was the end of that story. It had taken a lot longer and cost more than either I or the customer had anticipated. But he accepted it all philosophically, collected the set and delivered the second one; the one with the red cast. Too much red 9.6V shown on pin 14 ofIC201. So we put that one on hold for the moment. My thoughts went back to IC302 and the fact that adjusting the colour control not only affected what colour there was to be seen, but also the brightness which, in my book, was all wrong. A toss-up So what it all boiled down to was a toss-up between these two ICs. Was it IC201, as suggested by the seemingly small voltage change on pin 14, but about which I was not sure? Or was it IC302, as suggested by the interaction between the colour control and the brightness function and which I felt sure was incorrect? Not having either IC in stock, I had to make a choice and hope I ordered the right one. If Murphy had his way, of course, which ever one I ordered would be wrong, but I had to make a decision. After some thought I plumped for IC302 but, as it turned out, Murphy was having two bob each way. So the IC was ordered, was duly delivered and fitted. I then switched on and waited for the tube to warm 22 SILICON CHIP up. As it did, I was relieved to see a picture come up on the screen; it seemed I had made the right choice. But the joy was short lived. We had a picture all right and we had proper colour saturation control, but the picture was still too bright. It was not as bright as before but was still brighter than normal and, more importantly, there was insignificant control from the brightness pot, R30. So it was back to IC201 and the brightness control voltage. It appeared that my original doubts about the voltage range might be justified. In an effort to determine what this range should be, I disconnected this line from the main board, at pin 1 on the control board (this is actually a wirewrap connection). It was a different story now. With the line effectively disconnected from IC201, the voltage ranged from 9.5V to 11.5V; figures which made a lot more sense. But there was still about 9.5V on pin 14 and the picture was still too bright. I tried bridging pin 14 to chassis with some low value resistors, hoping to brute force the situation, but this had little effect. All of which forced me to accept Once again, his description of the fault was quite accurate; it was very red. Initially, I tried juggling the cutoff and drive presets, R102, R104, R106, R108 & Rl 10. However, it quickly became obvious that, while this produced some improvement, the error was far beyond such adjustments, even assuming that such an approach could be justified. And clearly, it wasn't. A voltage check around the red output stage confirmed what I now suspected; the stage was turned hard on. The voltages marked on the circuit suggested that this stage was normally turned on the least, but its collector voltage was now well below the other two. So, after a few more routine checks, I was forced once again to the conclusion that it was IC302. It was all getting rather monotonous but I ordered another one, which duly arrived and was fitted. And that fixed it. Or, rather, it did after a grey scale routine, my fiddling with the drives and cut-offs having put everything out of whack. So that finished that job and, after the customer had taken delivery, I mentally wrote both sets off. Murphy strikes But there was more to come. Some six weeks went by and then the customer was on the phone again. The first set was in trouble again and, judging by the customer's description, behaving just as it had the first time. I didn't trust myself to say more than, "Bring it in again". TETIA TV TIP Philips KT3A-2 chassis. Symptom: Bright red, blue or green screen, with similarly coloured retrace lines. The effect is exactly like a heater-cathode short in the picture tube but the heatercathode voltages remain near normal. The other cathode voltages can be greatly modified. Cure: Transistors 0241 (red), 0257 (green) or 0273 (blue) short circuited. The transistor is a PNP type BC558. On this occasion the fault was heat sensitive and was totally absent while the cabinet back was removed. is TETIA TV Tip supplied by the Tasmanian branch of the Electronic Technician's Institute ofAustralia. Contact Jim Lawler, 16 Adina St, Geilston Bay, 7015. Privately, I had a horrible fear that one of the ICs had shot its bolt again and that wasn't going to look very good, even to a trusting customer. And a quick check on the bench did little to reassure me; it was turned on just as hard as before, if not harder. The only bright spot was that I was now much more familiar with the circuit and layout. I went straight to the collectors of the three driver transistors, which all turned out to be well down; more so than before. This difference encouraged me a little; perhaps it wasn't an IC after all but something more fundamental. I went straight to pin 16 (video out) of IC201 and checked the voltage. It was close enough to normal. I moved on to the base of the video output transistor, X201. This was still normal, being virtually the same point, but the emitter and collector voltages told a different story. The emitter should have been at 6.5V but was actually closer to the +12V on the supply rail. And the collector, normally at 0.3V, was also way up, only slightly below the emitter voltage. Well, that was the answer, at least in broad terms. But why? My first impulse was to suspect the video output transistor and I went through the voltage check again, while I speculated. And as I prodded one of the legs , the set suddenly came good. And that was it. I had moved the collector resistor, R214, and further investigation revealed a subtle, but quite definite, dry joint between one of its pigtails and the copper pattern. A hot iron and some solder had it fixed in a jiffy. Well , that was a relief. But imagine the fuss a suspicious customer could have made. I can just hear the complaint. "Had the set for nearly a fortnight, charged me "x" dollars , then six weeks later it broke down again. Y'can't trust these blokes; leave themselves another job every time". Of course, nothing like that happened with this customer. In fact, we both had a bit of a laugh about it when I explained what had happened. And I didn't even charge him; it was on the house. But it can be a trap. Australian Made TEST EQUIPMENT YOU CAN TRUST SHORTED TURNS TESTER Built-in Meter to check EHT transformers including split diode type, yokes and drive transformers . $78.00 + $3.00 p&p DEGAUSSING WAND Strong magnetic field , larger than usual coil with multicore centre. Double insulated for your safety, also fitted with momentary on/off switch. 240V A/C 2.2 amps. Just about as important as having a soldering iron in your toolbox! $75.00 + $10.00 p&p HI-VOLTAGE PROBE Built-in meter reads positive or negative 0-50kV . For checking EHT and focus as well as any other Hi-tension voltages. Anew twist $98.00 + $5.00 p&p To change the subject, I have had several examples recently of a new twist to an old fault; a twist which fooled me the first time and cost me a couple of wasted hours. The sets in question were the old faithfuls, the Philips K9 and K11. I have had three of these in for repair recently, in as many weeks. And, yes, there is still a lot of them around, alive and kicking. The twist was that, while it was a fault with which I was very familiar, the symptoms were quite different. Add to that a sneaky red herring and one of them had me running around in circles. The K9 and Kl 1 use very similar circuits, the main difference being that the K11 uses a varicap pushbutton type tuner. However, the sections of interest in this story, the power supplies, are so similar as to be virtually interchangeable. The set that caused me all the problems was a Kl 1. It belonged to a long standing customer and I had serviced it on a number of occasions over the years. This time, it was suffering from a madly hiccuping power supply. It's not an unusual fault in these sets and, over the years, I have developed various approaches to it. Basically, one needs to determine whether the fault is in the power supply itself or whether it is a fault in the set which the power supply doesn't like. Often, one can get a clue by monitoring the main HT rail, which nor- REMOTE CONTROL TESTER (INFRARED OR ULTRASONIC) Designed to test lnfrared or Ultrasonic control units. With the extension lead you can also test infrared units which cannot be placed in front of the testing unit. Requires a 9V battery. Output is via the LED diode and piezo speaker. $85.00 + $4.00 p&p LASER DETECTOR PROBE A new addition to the remote control tester. Comparable with units costing $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 tester. Helps you determine if you have a tuner problem, an AGC problem or a fault in the IF stages. $250.00 (Tax inc.) TUNER REPAIRS from $17.00 exchange + p&p Cheque, Money Order, Bankcard or Mastercard ~v. TUNERS) · ·· · ·· · ······ · ••·.•-•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:-;-;,;,:-:•:•:-:-:•:•:•:•:::::::::f::;:::-:-· 216 Canterbury Road, Revesby, NSW, AUSTRALIA, 2212 'iEr (>~ (02) 7741154 (02) 774 1154 OCT0BER1991 23 SERVICEMAN'S LOG - CTD But replacing it, essential though it undoubtedly was, did nothing for the hiccups. By now there was only one component left; the chopper transistor, TSl 70. Initially, I simply disconnected the leads to it and made an in -situ test. This indicated that the transistor was perfect but, having been caught that way before, I decided to pull it out and replace it anyway. And what a mess I found. The insulating washer between the transistor and the heatsink had carbonised to the point where it fell to pieces when I tried to remove it. And that was it; I fitted a new washer and the set was up and running. Damaged T0-3 insulating washers are a common problem in the power supplies of old Philips K9 & Kll sets. A third washer completely disintegrated when it was removed. Why didn't I twig? mally sits at around 155V, and noting I had a chance to look at it again. By the value it reaches before it collapses. this time, however, the Variac was I do this by connecting the set to a tied up with another job, which I Variac and winding the supply voltdidn't want to disturb. age up until the set hiccups. In this I thus decided to apply full mains case, the system collapsed at around voltage and see what happened; 65V which is similar to the effect cre- maybe the faulty component would ated by a faulty tripler. I tended to show itself under pressure. Imagine doubt this possibility in this case, bemy surprise when the set produced a normal picture, without so much as cause a new tripler had been fitted only a few months previously. Still, any sign of a hiccup. stranger things have happened, so I An intermittent fault? There was disconnected the tripler. But it had no nothing for it but to pull the Variac effect. out of its current role and go through The next trick is to substitute a the previous test again. And, sure known good power supply. This is enough, at around 130V it hiccuped. somewhat easier with these sets than But when I notched the Variac up a with many others, for a couple ofrea- few more volts it stopped and I pressed on until I had the normal 155V HT. sons. One is that it is physically relatively simple and the other is that I And there it ran for the next half hour have several such units on hand, sal- and never missed a beat. I fished out a second spare board, vaged from other sets which have long fitted it and went through the whole gone to their last resting place. procedure again, with exactly the same It took only a few minutes to fit a spare, then I wound the supply ·volt- result. By now I realised I'd been had. I couldn't explain the spurious hicage up again, while monitoring the HT rail. This time, all went well as it cup, but spurious it certainly was; the went past the previous 65V limit and whole incident was a red herring. I was hoping for a clear run. But at It was all very frustrating but at around 130V the system began hic- . least I was now sure that the fault was on the set's own power board. So I cuping again. This different voltage level was a proceeded to go over the board, combit of a puzzle but I now felt sure that ponent by component. A frequent the power supply was not at fault . cause of this fault is the 225µF smoothHowever, after spending some coning capacitor, Cl 78a, following the siderable time checking out all the bridge rectifier. This sometimes has a other likely possibilities in the set, I dry joint to the board pattern and drew a complete blank. sometimes it simply dries out. Pressure of other work intervened In this case, the capacitor was .at this stage and, in any case, I needed quickly cleared. Next, I discovered time to think. So it was that the set sat that a 680kQ resistor, R171, was open on the bench for a couple days before circuit and I thought I'd struck oil. Now I know that someone is going to say that I should have twigged to this fault in the first place, since it is a regular problem in this set - and others. What's more , I have described this breakdown, in the K9 and Kl 1, in these notes in the past. Which is fair enough. Except that, in all previous cases, this fault has taken out the chopper transistor and the 2A fuse between it and the bridge rectifier. They are classic symptoms; never has it simply caused hiccuping. In fact, the first of the three sets exhibited those classic symptoms and I had it up and running in short order. And that's what threw me. That and the aforementioned red herring. Of course, I swore I'd know better next time. And I did too but the next time came sooner than I had expected; less than a week later, there was a K9 on the bench, hiccuping away merrily. I despatched it in short order. More to the point, I am wondering about that insulating washer. While we tend to refer to these as mica washers, they are not always mica and this one certainly wasn't. It was (blue) plastic. Now I've no doubt that, commercially, the plastic version has much to recommend it; it's probably cheaper, more robust and easier to store, to name just a few of the advantages that I can think of. But is it as good as mica? Is it, in the long term, chemically unstable with a couple of hundred volts across it? Some plastic capacitor dielectrics have exhibited characteristics along these general lines, limiting their use in certain applications. Well, it's just a thought. SC 24 SILICON CHIP --;.-;,-;,-;,_-;..-;.,-;..""'.'"...,-..,.--::--.-.---.-----... .. - --..._-r<,-r",_S'_S_-::!'_~,;;~;.;;.;;- 8088-12 8088-31 286-12 286-16 286-16Neat 386SX-16 386SX-20 386-25 386-33 486-25 486-33 Was OK RAM OK RAM OK RAM OK RAM OK RAM OK RAM OK RAM OK RAM OKRAM OK RAM OK RAM $ 135 $ 199 $ 245 $ 449 $ 499 $ 695 $ 795 $1495 $1995 $3995 $4495 Now $ 99 $ 149 $ 199 $ 299 $ 325 $ 525 $ 625 $ 895 $1195 $2650 $2795 386SX- N';;t";bo';;k\ 1 ·------------------ 11 Processor: 80386CPU8/16MHz 11 Display: Backlit LCD640x480pixels. VGA,EGA, CGA, &MDA Compatible I I Memory: 1MbofRAMonboard,expandablero8Mb 11 Drives: 1.4Mb3.5"FloppyDiskDriveplusa40MbHardDrive I I Ports: RS-232 Serial Port, Parallel Port, External 16 bit extension Port. External VGA & External FDD ( 1.2M) 11 ports.BuiltinNi-Cadbatterywithlowbatterywarning 11 lampandACadapter.Dimensions:280mm(W)220mm(D) 50mm(H) 11 Weight: 3.2kg,'7lbs 11 II II ~-- - - -- - - --- - - -- - -J ~ : 42mB Western Digital : IDE Hard Disk : : I I I I I I To suit all XT's Including Controller card Normally .$'195.tm : This : Month • • $395. 00 l _________________ ) ~ (f\fTl 1YlI~J~i(£}l.!JllJ 286-16MHz Landmark Speed 21Mhz Computer Includes: $4495 •00 __ --- --_ ________________ J 14" Super VGA 1024 x 768 .28mm Dot Pitch $650 $874 Now $549 $649 $925 $995 $799 Was 14" Monitor with 16 bit 256K card with 16 bit 512K card (expandable to 1Mb) with 16 bit 1Mb 8514A mode VGA Card $699 rn~ I 2Year Compu:-=;w;;;;;t;----------..1 l Now includes DOS Ver 4.01 at no additional charge (Value $155.00) 386SX-16MHz Landmark Speed 21Mhz 386-25MHz Landmark Speed 41Mhz 386-33MHz Landmark Speed 56Mhz Includes: Includes: Includes: (No Cache) Includes: 64kCache lMbRAM-(Exp. to2Mb) I.2Mb or 1.44Mb Floppy, 42Mb Hard Drive 256K 16 Bit VGA card, 14" Super VGA Colour Monitor - 1024 x 768 2 S, 1 P, lG ports. Enh anced 101 keyboard 1Mb RAM - (Exp. to 4Mb) 1.2Mb or 1.44Mb Floppy, 42Mb Hard Drive 256K 16 Bit VGA card, 14" Super VGA Colour Monitor - 1024 x 768 2 S, 1 P, 1 G ports. Enhanced 101 keyboard 1Mb RAM - (Exp. to 8Mb) 1.2Mb or 1.44Mb Floppy, 42Mb Har,d Drive 256K 16 Bit VGA card, 14" Super VGA Colour Monitor - 1024 x 768 2S, IP, lGports. Enhanced 101 keyboard 1Mb RAM - (Exp. to 8Mb) 1.2Mb or 1.44Mb Floppy, 42Mb Hard Drive 256K 16 Bit VGA card, 14" Super VGA Colour Monitor - 1024 x 768 2 S, 1 P, G ports. Enhanced 101 keyboard $1795.00 $2195.00 $2995.00 Larger Hard Drives for all Systems: Western Digital 85Mb add Conner 104Mb add Conner 120Mb add Extra Memory (per 1Mb) add $350.00 $495.00 $645.00. $125.00. Electronic Solutions Sales P/L YOUR GUARANTEE OF SATISFACTION: 5 Waltham St. Artarmon 2064 PO Box 426 Gladesville 2111 Telephone: (02) 906 6666 Fax: (02) 906 5222 $3395.00 .. • - == BI • All products carry a 14 day money back guarantee ( except software and chips). • All prices include sales tax. • All computer systems carry a full 24 month warranty. • All cards come with full documentation • All other products carry a full 12 month warranty. • All specials are for the month of magazine inserted or until stocks are exhausted Due to Technical advances, products we supply may in some cases vary from those pictured. In all cases the products supplied are guaranteed to perform to an equal or higher standard than those pictured CIRCUIT NOTEBOOK 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. Dual tracking power supply uses cheap parts This dual tracking regulator combines a 3-terminal regulator with discrete transistors. The positive regulator circuit is conventional enough. It consists ofan LM317 adjustable regulator which is used in conjunction with an MJ2955 (Ql) to boost its output current capability. Depending on the output voltage setting, it should deliver z amps or more. Op amp IC1 and transistors Q3 & Q4 provide the. adjustable negative supply. It works as follows: the two 4.7kQ resistors between the positive and negative output supply rails form a voltage divider which will normally result in 0V being applied to the inverting (-) input of IC1. This op amp drives Q3 & Q4 which act as current amplifiers to give a current capability in line with that of the positive regulator circuit. Transistor QZ and LED 1 act as a power monitor for the positive regulator. Provided that the output is around 1.ZV or more, LED 1 will be alight. Hence, if LED 1 goes out, the output is severely overloaded or short circuited. Q5 and LED 2 provide the same function for the negative regulator. Steven Merrifield, Newlyn, Vic. ($40) DC offset canceller for amplifiers Ideally, an audio amplifier should have no DC at the output but this is not easily achieved. Usually there is some input filtering (to block DC) and the feedback network often employs an electrolytic capacitor which sets the DC gain at unity. Even so, there are always DC offsets at the input and so these inevitably appear at the output. This proposed circuit eliminates most of these problems. It reduces the DC gain of the amplifier to much less 26 SILICON CHIP 02 BC548 240VAC V+ 10 + TANT+ .01+ 4.7k .01! .,. +5V ~ov 03 2N6124 4.7k -5V - 1+ 04 2N6130 V4700i 4.7k Fig.1: the circuit of the dual tracking supply. A TIP41 is a suitable substitute for the 2N6130, while a BD139 may be substituted for the 2N6124. than unity and it allows the lower 3dB frequency to be accurately set. It avoids electrolytic capacitors and even the need to block DC at the input of the amplifier. In fact, the output offset of the stabilised amplifier is determined by the difference in input offset voltages of two matched op amps and a gain factor in the circuit, such that offsets ofless than 5mV could be expected. If high tolerance components are used, then the lower 3dB frequency could easily be set to within several percent (less than 5%) without trimming. Another worthwhile feature is that the stabilising circuitry is effectively out of the signal path for those frequencies that we expect the amplifier to cover (ie, the audio band). The circuit is not ideal, though. It relies upon the matching between the two amplifiers in a dual op amp package and unfortunately this is not guaranteed. In my experience, you may expect to see a difference in input offset voltages equal to about half the offset voltage in a dual op amp. This is a bit disappointing but for op amps with reasonable specifications, good performance can be obtained from the Battery charging for garage door controller This circuit was designed to provide improved battery charging for the Garage Door Controller published in the March & April 1991 issues of SILICON CHIP. It also provides improved voltage regulation of the supply to the motor and the lamp. Refer to the circuit; the input bridge rectifier is retained but is now fed by 12V AC only. Its output drives a 7812 3-terminal regulator which delivers a +13.8V DC rail, as set by VR1. This +13.8V rail is then used to charge the battery. The advantage of this scheme is that battery charging tapers off smoothly after each operation of the door. For example, if the volt- circuit. The circuit is shown connected to the SILICON CHIP Studio 200 power amplifier module. Essentially, the circuit works as follows: IClb attenuates and inverts the . voltage appearing at the amplifier to be corrected (in this case, the Studio 200). IClb's output is connected to the input of ICla which is operating essentially without feedback for DC and low frequencies. Its output feeds into the inverting input of the power amplifier being corrected. In effect, ICla and IClb cancel any voltage appearing at the output of the power amplifier. Since we don't want this happening for audio frequencies, the 0. lµF capacitor between pins 1 & 2 of ICla rolls off the gain of the "corrector circuit" and thus determines the lower 3dB point of the power amplifier. Note that the normal 1QµF feedback capacitor of the Studio 200 is deleted. The design process requires some empirical working and it could take several attempts to get an acceptable set of component values. Start by selecting R3 . It should be several times greater than R2 so that the stabilising circuit has as little impact as possible on the signal within the required bandwidth, although this is not always essential. Bear in mind that it affects the low frequency 3dB point, the midband gain of the stabi- 1N40D4 F1 2A 12VAC ADJUST 100n age is set to 13.8V, the current reduces to just a trickle charge after a few hours if the door is not used again. The additional parts can be mounted on a small tagstrip which is then mounted adjacent to the bridge rectifier. It can then be wired into circuit by cutting the PC pattern between the output of the ·1 (OPTIONAL) INPUT •V1 AND BATTERY THROUGH 5A LINE FUSE bridge rectifier and diode D15 . Note that the 7812 regulator should be fitted to a small heatsink. Finally, the 12V lamp mounted on the case should be have a maximum rating of 12W to limit regulator current when the motor is running. P. Hunter, Bundaberg, Qld. $15 z.2k <>-7--fl--+-YIW,,--+-_.;;'-=f R1N llk.,. 330pf! R1 22k R4 470k R2 1k R3 22k .,. C R5 120k 0.1 lised amplifier and also the maximum low frequency input voltage (including DC) that the stabiliser can accommodate. The maximum DC input voltage that can be accommodated is given by: V1max = VA3max·R1R2/(R1R2 + R1R3 + R2R3) where VA3 max is the maximum output voltage of A3 (about 10V for an op amp operating from 15V supply rails). At this point, it might be necessary to adjust Rl or R2 to maintain the required midband gain of the stabilised amplifier using: VofV1 = 1 + R1(R2 + R3)/R2R3 Next, select capacitor C which should be in the range .00lµF to lµF and preferably polycarbonate or polypropylene. Plug the values into the following formula to get R4: R4 = R1/2n;R 3CfL where fL is the required low frequency 3dB point. Now, as op amp IClb amplifies the output of the stabilised amplifier, IClb's gain must be set to avoid b(:).ing overdriven. Set the gain of IClb using the following formula: R5 = R4 V Bmax/V 0max, where Vamax is the maximum output voltage ofICl b and VOmax is the maximum output voltage of the amplifier to be stabilised. P. Denniss, University of Sydney. ($50) OCT0BER1991 27 FREE CALCULATORS - AMAZING OPPORTUNITY An American lndustrlallst once remarked "I believe that half of our advertising Is Ineffective - the trouble Is, we don't know which halfl" Well - as the year draws to a close we've decided to conduct a survey on our advertising I.e. to see where our advts are noticed most. 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 delighted to send you absolutely without charge one of our fantastic X 2110 Desk Calculators - there Is no obligation - you do not need to make any purchase. (Limit one per customer). 300 Watt Inverter 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. Features: • 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 building • Built in piezoelectric siren gives different signals to indicate different functions • Sends signal down power line to activate remote siren • Programmab le arm/ disarm switch buttons Paaslve Infra Red Movement Detector Go anywhere 240V main■ powe r from your car battery with 1h11 tanta1llc 12V DC to AC Inverter. Remote Reed Switch This compact inverter will power lights, power tools, electric shavers, radios etc . A must for farming, camping, mini ng, boating and wherever 240V power isn 't available . This consists of an enclosed reed switch and transmitter with a magnet. Ideal for the loungeroom, family room or hallways. Mounts up on the wall or bookshelf. Detects movement within an area of 9 x 9m. Featu re■ : • Complete with over current circuit breaker • Fused 240V output • Built in panel meter to monitor output vo ltage • Strong steel chassis. Remote Plezo Alarm 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 the main control unit. SYSTEM 1 $ 39 1 x Mai r Cont rol ler 3 x Rem ote Reed Sw itches Pl us 4 Bonus Large Alar m Warn in g Sticke rs 9 This Month Only NORMALLYSB&,S- NORMALLY $249 $5,:Mr Includes: 1 _l( Mam Cont rol ler 1 x Remote Reed Swi tch 1 x Remote PIA Move men t Detec to r 1 x Re m o te Key pa d Plus 4 Bonus La rge Alarm Wa rn ing St ickers This Month Only Rated Power Input . ... 60W Max. Power Input . . ... 100W Impedance (300Hz) ... 8 Ohm Frequency Response . to - 4kHz Resonant Frequency . . 45Hz(+/ -9Hz) Sensitivity ...... ...... 98dB/W(0.5m) Excellent bu1 regl1ter performance C3065~o$6O 12" Woofer 100 Watts RMS Rated Power Input . .. . 100W Max. Power Input .. . .. 150W Impedance (200Hz) .. . 8 Ohm Frequency Response . to - 3kHz Resonant Frequency .. 30Hz(+/ -6Hz) Sensitivity .. .. .. .. . . . . 98dB/W(0.5m) . C 3070 $9Sho $ 8 5 15" Woofer 120 Watts RMS Rated Power Input . .. . 120W Max. Power Input ..... 20-0W Impedance (200Hz) ... 8 Ohm Frequency Response . to - 15kHz Resonant Frequency .. 25Hz(+/ -5Hz) Sensitivity .... . . . ..... 98dB/W(0.5m) C3075$~oo$95 $299 Thll Month $12.oo 10" Woofer 80 Watts RMS Rated Power Input .... aow Max. Power Input .. . .. 130W Impedance (400Hz) ... 8 Ohm Frequency Response . to - 4kHz Resonant Frequency .. 28Hz(+/ -5Hz) Sensitivity . .. . .. . . .. . . 97dB/W (0.5m) C 3026 $.9Sh5 $ 8 5 12" Woofer 80 Watts RMS Rated Power Input. . .. BOW Max. Power Input .. .. . 160W Impedance (30-0Hz) .. . 8 Ohm Frequency Response . to - 3kHz Resonant Frequency . . 25Hz( +/ -5Hz) Sensitivity . . . .. ..... . . 98dB/W(0.5m) C 3030 $j.26'.oo $ 1 0 5 10 up $ 1 O .oo Up to 30% Off Pol y Emulsion Coated Cone 10" Woofer 60 Watts RMS C 3012 S28':so NORMALLY~ Quality Speaker Bargains Polypropylene Dome Twuter With Fe rro Fluld 60 Watt Max. Power. Sil ky smooth frequenc y response 1.5Hz to 20kHz. Wide angle dispersion . Massive power handling capacity. Diam . 94mm . High spectrum . Purity. Incredible low price! SYSTEM 3 Includes: 1 x Mai ., Con troll er 3 x Remote Reed Sw itches 1 x Remo te PIA M ovemen! De tet::to r 1 x Rem o te Keypa d 1 x Remo te Si re11 Plus 4 Bon us Large A larm Warn ing Stickers This Month Only Superb Dome Tweeter Bargain of 1991 Less Than ½ Price! With Barium Ferrite magnet,. Very efficient extremely low JlItortlon (we 1upply the ■e driver■ lo 1ome highly re ■ pected 1peaker 1y1tem r,:,_aker■ ) '""''\;;, \ Carbon Fibre 6½" Woofer 30 Watts RMS Rated Po wer Input . . .. 30W Max. Power Input ..... 70W Impedance (300Hz) .. . 8 Ohm Frequency Response . to - 6kHz Resonant Frequenc y . . 65Hz(+/ -13Hz) Sensitivity ....... . .... 97dB/ W(0.5m) C 3034 $821's $ 6 9 8" Woofer 60 Watts RMS Rated Power Input .... 60W Max. Power Input .... . 100W Impedance (400Hz) . . . 8 Ohm Frequency Response . to - 5kHz Resonant Frequency .. 50Hz (+/ -10Hz) Sensitivity . ..... . . . ... 98dB/W(0.5m) C 3036 $ ~ 55 $ 8 9 15" Woofer 100 Watts RMS Rated Power Input. ... 10-0W Max. Power Input. .... 200W Impedance (400Hz) .. . 8 Ohm Frequency Response . to - 3kHz Resonant Frequency .. 25Hz(+/ -5Hz,' Sensitivity. . .. . 98dB/W(0.5m) C 3032 $ ~ 0 0 $ 1 6 9 With Barium Ferrite magnet ■ . Similar In performance to our emulaion cone range but with quite Hlonlohlng power handling capacity 4-Channel Lighting Desk 120 Watt Public Addre 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 . This professional quality Public Address Amplif offers performance equal to or better than commercial units at about half the price. Ide suited for Halls, Churches, Clubs and even temporary setups. Input• 2 balanced microphones with 3 Pin X connectors. 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 Watts into 4 Ohms; watts into 8 Ohms; 120 watts into 100V AC line . Ksm$329.oo Powerhouse 600W Digital Altimeter Get 240V AC Maino Power From Your 12V Battery With Thi• Handy 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 !O running power tools , l ighting (includ ing 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 1Oft resolution . It has a barametric pressure offset adjustment for heights up to 5000 feet and is ideal for use in ultralights, gliders, hanggliders and balloons. K258o$299.oo LED Digital Tachometer K6770 Kit Verolon $ 4 9 9 .00 K 6774 Fully Bull! $ 6 2 5 & Tailed 12V Input K 6775 Fully Bull! & Tailed 24V Input $625 .00 .00 300 Watt Inverter with Auto Start EA April '88 • 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 we ight • 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 • eas y to build as there is very little internal wiring. K 6750 Kit Verolon $279.oo S/C AUGUST '91 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 tel l you . It works with all ignitions from Kettering to Hall Effect systems and with 4, 6 and 8 cylinder cars. K 6755 Fully Bum and Teoted $379.oo EA Aug '85 This inverter is ideally suited for powering low wattage mains appliances from the car battery while camping . Typically , it can be used to power an electric shaver, electric blanket , electric can opener or a 40W light bulb . K 4320 $31.oo K 6705 Kit $99.oo 8 Channel Audio Mixer Credit Card 6 Mic & 2 Aux Inputs with Canon Soc kets. Treble, Bass & Master Controls. Multimeter 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. A2051 $ 3 9 9 .oo . a 1060 Normally $_65'.oo Thi• Month $32.so Casio Printin Calculator Bargain • 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. 10 Watt High Performance Wireless Microphone ?:'!!i ! ~p~pne Requires 8 x AA cells (not suppliPd ). Includes ~; ectronic wh istle activated by button in the handle. Incorporates ALC circu itry (Automatic Level Control ) which hel ps eliminates distortion caused when input levels are too high . Can be received on any FM radio. Very professional mic. Built-in Antenna. C 0328 $129.so A 198o.$-1-29:"oo High Quality Ent Microphone ,4. UHi the famou1 Shure SM 58 lnHrl ·Assembled in Taiwan, however in our humble estimation sounds every bit as good as the American assembled product. Fantastic value at this price. arris Four Channel Digital R Thl1 remarkable product can be ■Imply twitch Htect programmed to I LITERALLY DOZENS OF APPLICATIONS/ X 2125 Normally $.,149.95 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. Thi• Month $99.oo A 2100 $799.oo Toroid Power Transformers Why a Torlod? NEO,,RENE WASMEMS I Save 20% or more 160VA SEC Sec. V Current A Current B 12+12 6.6 3.3 18+18 4.4 2.2 25+25 3.2 1.6 30+30 2.6 1.3 35+35 2.2 1.1 $89:ss- 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 $ ~ 9 5 Now $ 1 1 ,00 'II~ I ?,0•• e:,► Cat. No M 3050 M 3055 M 3060 M 3065 ~ now$5O.oo SEC SEC Sec. V Current A Current B 12+12 13.3 6.7 18+18 8.9 4.45 25+25 6.4 3.2 30+30 5.3 2.7 M 3070 35+35 4.6 2.3 M 3075 40+40 4.0 2.0 M 3oao__4,..5+_4_5___3_._ 56...,._ _ 1_.7,.8 SO0VA now$72.oo SEC SEC Sec. V Current A Current B 12+12 • 18+18 25+25 30+30 35+35 40+40 45+45 ~ NEW MODEL NOW /NCORPERA TES JAPANESE CERAMIC CARTRIDGE I T 2446 $49.s5 now$4O.oo SEC • Smaller size and weight to meet modern "Slimline" 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 Cat. No M M M M M 3120 3125 3130 3135 3140 M 3145 M 3150 M 3155 now $99.oo $.l.29:oo SEC SEC Sec. V Current A Current B 30+30 35+35 40~40 45+45 50+50 55+55 60+60 65+65 16.6 14.2 12.5 11.1 10.0 9.0 8.3 7.6 8.3 7.1 6.2 5.5 5.0 4.5 4.10 3.8 Aviation Headset WHY PAY $400 OR MORE FOR A DAVID CLARK SET? • High performance. noise attenuating earphones. • Noise cancelling microphone• Cushioned head pad •Super sturdy • Great performance • Superb, professional pilot's headset will last a lifetime with reasonable treatment • Includes standard 8ircraft jacks. May be used to provide isolation between Telecom Australia lines and mains operated equipment. Telecom approved to specifications 1053 and 1054. Durable die cast aluminium frame. 240V Models 30CFM Air Flow 80mm x 80mm x 32mm F 1020 $32.95 80 CFM Air Flow 120 x 120 x 38mm F 1030 $32.95 24VDC Brushless Model t":M, •-----·- •···=~··=--· rooL . SELLING •h~ ~~~icf[o1i~NG Ideal for the service technician and hobbyist alike. This lightweight de-soldering iron allows components to be quickly and cleanly removed with one hand. Naturally it's SEC approved and comes with a cleaning wand. Can be used as a soldering iron. T1250$~5 This Month $ 4 9 .95 Micron Soldering Station 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 Impedance: 600 Ohm line/ 600 Ohm equipment. , Hi-Specification Computer Fans Multiple De-Soldering Tool Temperature Soldering Iron Multi purpose T 2440 Normally $:,..sg.95 1OOVA Transformer Thi• Month $14O .oo Another quality transformer from MK 11 Repla ce ment Tips Altronics. Wound on expensive grain oriented steel. HALF PRIC::!E:...:1;..i.~~~ lj;-1(-'.~2''::=_~':J} Primary: 240V Secondary '·1 12V 8.3A 15V 6.6A 24V 4.1A 27V 3.7A 30V 3.3A • ~• - •.JI · c 9070 Only $189.oo All $5.50 ea T 2427 0.8mm T 2428 1.6mm T 2429 3.2mm • ~· Dalo Pe~s Breadboards T 0033 $4.oo • Standard 0.1 inch spacings • Accepts all LSl's semis, transistors, diodes, leds and passives 120mm x 120mm x 38mm MA 2170 $--95 F 1040 $29.95 This Month Only $ 1 5 .00 'D' Series Computer Connectors. P 1000 100 Holes $3.25 P 1005 640 Holea $12.so P 1007 640 & 100 Holes $ 1 4 .so P 1012 400 & 1280 Holes $44.60 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 DB9 Male 9 pin connector DB9 Female 9 pin connector DB9 Male rt/ I PCB connector DB9 Female rVI 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 Backshell cover DB25 Male 25 pin connector D825 Female 25 pin connector DB25 Male rt/ I PCB connector DB25 Female rVI PCB connector DB25 Male straight PCB connector DB25 Female straight PCB connector DB25 Backshell cover WAS ,;ow 10 Up $ $ $ $ $ $ $1.55 $1.60 $3.40 $2.20 $2.50 $3.40 $1.50 $1.95 $2.40 $3.95 $4.40 $1.35 $1.40 $3.00 $1.95 $2.35 $3.00 $1.35 $1.65 $1.70 $3.75 $3.75 $4.40 $2.70 $1.90 $3.10 $3.75 $2.50 $1.75 $2.25 $3.30 $4.40 $4.40 $3.90 $5.50 $2.05 $2.50 $3.95 $3.50 $3.50 $5.25 $1.85 s$ .~o5 ·r $ . 5 $ P 1015 500 & 1920 Holes $65.oo Metal backing plate for shielding of sensitive clr,c uitry. Circuit Breakers Now there's no need to pay $10 or more for a circuit breaker. Altronics product is USA Underwriters Laboratories listed (and tha t speaks for itself) and once again is an Altron ics Price Breakthrough. S 5503 3 Amp S 5505 5 Amp S 5510 10 Amp S 5515 15 Amp :' S 5520 20 Amp ' . S 5525 25 Amp An$4.5o MU Metal Shielded Audio Transformers Oh~ -w ~ Microphone Type Primary: 200 Ohm Secondary: SOK M 0101~5 . , . . Brldglng/l1olallng Type -·use .,,- $2 S.oo each for coupling audio modules. Nominal impedance ratio 10K: 10K (1:1) M0702~95 Cet No. Unit A Height 5011 1U 44 5012 2U 88 5013 3U 132 5021 1U 44 5022 2U 88 5023 3U 132 H 5031 1U 44 H 5032 2U 88 H 5033 3U 132 H H H H H H FHtu'": • Raw aluminium, black or natural anodised finish • These beautifully crafted rack cabinet boxes will give your equipment a really 1_st 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. ~ ~ Australian Designed and Manufactured Professional Series Modular Rack Frames 32 76 54 32 76 54 32 76 54 38 79 122 38 79 122 38 79 122 Raw Alum. RawAlum. RawAlum . Nat Anod . Nat Anod . Nat Anod . Blk Anod . Blk. Anod. Blk Anod. • REVOLUTIONARY NEW EXTRUDED DESIGN EL/MINA TES THE NEED FOR l'ISABLE BOL THEADS THROUGH THE FRONT PANEL ------- 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 in either Natural Anodised aluminium or Black Powder Coat aluminium and the side panels in Electric Blue or Black Powder ~~!\ \~)s~se in home Hi-fi systems, Professional Aud io installations, Band· ~ Gigs, Computer Patch panel etc . H H H H H H tt H H H H H 5204 5205 5206 5207 5212 5213 5218 5219 5230 5231 5238 5239 Rack frame 4U Nat. Panel set for H 5204 Rack frame qU 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 Wer Now $1 $ $1 $ 5 $1 9 9 $ 89 10 29 159 289 195 $125 $44 $135 $49 $152 $80 $170 $99 $205 $143 $242 $175 Now 5304 5305 5306 5307 H 5312 H 5313 H 5318 H 5319 H 5330 H 5331 H 5338 H 5339 H H H H 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 $125 $44 $135 $49 $152 $80 $170 $99 $205 $143 $242 $175 Enables rack mounting of tuners , videos, C.D. players , amplifiers etc. which normally can 't be rack mounted. Supplied in flat pack form easily assembled in minutes. Available in black only. STOP PRESS - NOW AVAILABLE IN 2 I 4 UNIT SIZES I H 5352 2 Unit (88mm) $49.95 H 5353 3 Unit (132mm) $49.ss H 5354 4 Unit (176mm) $55.95 Great Value Altronics Kits 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. K 5560 $29.95 M 9020 12V AC Adaptor To Suit $16.95 Beat Triggered Strobe Add Some Life To Your Next Party Flashes in time to your music. Will also work as normal strobe. K 5790 $79.95 K 5795 Two Tube Option $16.50 Universal High Power Amplifier Module K 5140 $ 6 9 .oo 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 inc ludes angled heatsink brack et , main heatsink and unlike other kit suppliers, the in-bLl :11 Pol yswitch for loudspeaker protection. , Speech Synthesizer 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 open s. K 1915 $J.5,:tro Thll Month $29.oo Here 11 • Hlf contained Speech Syntheolzer thal doe1 not require a computer to control It. It can be connected to almost an y applian ce, vehicle or home remote control system to let you know when the kettle has switched off, t~,e doors are locked or the water in the radiator is boiling . Blank Eprom inc luded . Playmaster Pro Series 1 Power Amplifier Module K9500$~ Fantastic for use in Juke boxes, amplifier racks (multi-amplifier setups) discos etc . Thie Month Only $ 8 5 .oo K 5170 $85.oo K 9502 Pre-Programmed Eprom $2O .oo 174 Roe St . PERTH W.A. 6000 Phone (09) 328 2199 PHON E ORDER TOLL FREE 008 999 007 MAIL ORDE R C/ - P.O. Box 8350 Perth Stirling St . W.A. 6849 STANDARD DELIVERY I PACKING CHARGE $5 .50 to 1Kg, $8 1Kg-5Kg . AUSTRALIA WIDE - Via . Australia Post allow approx 7 days for delivery. OVERNIGHT JETSERVICE Up to 3Kg is $10.00, 3Kg to 5Kg is $28 .00. Overnight JetHrvlce Courier for delivery next day Country areas please allow additional 24-48 hours. HE AVY HEAVY SERVICE - All orders of 10Kgs or more must travel Express Road Please allow 7 days for delivery. $12.00 to 10Kgs. $15.00 over 10Kgs. INSURANCE - As with virtually every other Australian supplier , we send goods at consignees risk . Should you require comprehensive insurance cover against loss or damage please add $1.00 per $100 of order value (m inimum 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 . 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 DHlera are highlighted with a ■ These dealers generally carry a compreh ensive range of Altronic products and kits or we'll order any required item for you . Electronics ■ (098) 412681 Mic ro Electron ics (098) 412077 BUNBURY Micro Electroni cs (097 ) 216222 ESPERANCE Esperance Communications (090) 713344 KALGOORLIE Todays Electronics ■ (090) 215212 MANDURAH Lan ce Rock Retravision (09) 535 1246 Micro Electronics (09) 5812206 PORT HEDLAND Ivan Tomek Electronics (091) 732531 ROCKINGHAM TV Joe's (09) 5271806 NT ALICE SPRINGS Farmer Electronics (089) 522388 DARWIN Ventro nics (089) 853 622 VIC All Electronic Components (03) 6623506 The Electronic Component Shop ■ (03)_ 6706474 BORONIA Ray Cross E:ectronics ■ (03) 7622422 CHELTENHAM Talking Electronics (03) 5842386 CROYDON Truscott Electronics ■ (03) 7233860 PRESTON Preston Electroni c s ■ (03) 4840191 COUNTRY BAIRNSDALE LH & LM Crawford (051) 525677 BALLARAT Ballarat Electronics (053) 311947 BENDIGO KC Johnson ■ (054) 41 1111 MILDURA McWi lliam Electronics (050) 236410 QLO Delsound PL ■ (07) 8396155 NEWSTEAD ECQ Electronics (07) 2541153 WEST END B.A.S. Audiotronics (07) 8447566 WOODRIDGE David Hall Electroni c s ■ (07) 8082777 MAROOCHYDORE MALS Electronics ■ (074) 436119 MARYBOROUGH Keller Electronics (071) 214559 PIALBA Keller Electroni cs (071) 283749 ROCKHAMPTON Access Electronics (East St.) (079) 221058 TOWNSVILLE Super Solex ■ (077) 724466 SA Force Electronics ■ (08) 2125505 BRIGHTON Force Electronics ■ (08) 3770512 CHRISTIES BEACH Force Electronics ■ (08) 3823366 FINDON Force Electronics ■ (08) 3471188 HOLDEN HILL Force Elect·:onics ■ (08) 261 7088 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 Elect ronics ■ (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 Newtek Electronics ■ (042) 271620. WA COUNTRY ALBANY BP Special project for model railroads SteamSound Simulator Mk.11 Did you build the SteamSound Simulator project described in the April 1991 issue or are you contemplating doing so? Either way, this second version will be of great interest because of its improvements and its ability to be fitted into the loco's tender rather than a following wagon. By DARREN YATES & LEO SIMPSON There's no doubt about it, the SteamSound Simulator created a great deal of interest and already many hundreds (perhaps 500 or more) have been built. But like many new ideas, once it had been done, people could see ways in which it could be improved. And those people were not backward in coming forward so we had quite a lot of feedback on the project. 32 SILICON CHIP One big problem is associated with the idea of building the SteamSound Simulator into a wagon to follow the loco. It means that if you want steam sound with a particular loco it always has to be hitched to the wagon. That does not always lend itself to realism as there are times when the loco needs to be operated on its own (known as "light engine" to rail fans). Alternatively, if you want the steam sound with another locomotive, you either need another SteamSound Simulator or else need to unhitch the wagon and hitch up to the second locomotive. That brings us to the problem of compatibility with the wide range of locomotives available. We found that while the Simulator worked stunningly well with some locomotives it was no good with others; they would be off and running around the track before the circuit emitted so much as a single chuff. The problem relates here to two motor characteristics: back-EMF and motor starting voltage. Some model locomotives have much higher back-EMF for a given speed than others and some of the better brass locomotives with can motors will start with as little as 1V across the track. To be frank , we found that the original circuit just could not cope with the wide range of possible variations, even if some of the components were changed. So the part of the circuit which monitors the loco backEMF has been changed quite markedly. Even so, there are two resistors which need to be selected to suit the particular loco. The second problem with the circuit relates to breakthrough of pulsed track voltage into the SteamSound circuit, particularly at low track voltage settings. With some locos starting with track voltages at 1V or less, the equivalent input voltage to the 12V 3-terminal regulator was not enough to ensure proper regula'tion. To solve this problem, we have re-designed the circuit to work from a 9. 7V rail rather than 12V. The change to a 9.7V supply means that a number of other component values also had to be changed. Still more changes relate to the effort to make the circuit components as small as possible. To this end, we changed the values of the various electrolytics so that they are as small as possible, consistent with good sound effect. And because we changed the capacitors, there has been a "ripple through" effect whereby we had to change a lot of resistor values too. The net effect is that while the circuit configuration of the Mk.II version is very similar to the original, there are a great many value changes. Other changes relate to the design of the PC board. It has now been designed to use much smaller resistors and a TO-92 style 3-terminal regulator instead of the larger TO-220 unit used in the original unit. Finally, to allow the PC board to be crammed into a locomotive tender, it has been designed so that it can be cut The new Mk.11 version of the circuit is built on a PC board which can be cut into two halves & mounted inside the locomotive's tender. Use a piece of foam insulation between the two boards to prevent shorts. in half. The two halves can then be stacked for best fit. New speaker Many of the foregoing changes would not have been contemplated if an alternative to the relatively bulky and expensive speaker origin~lly specified had not become available. This new unit is extremely small, with an overall diameter of only 2 7mm and a front-to-back depth of 9mm. In spite of this, it is surprisingly efficient. In fact , it pumps out a level of steam sound which is truly amazing. There are two sources for this new speaker which has a clear Mylar diaphragm. First, you can buy them from Jaycar Electronics at just $2.50 (Cat AS-3002). A second way to obtain the speaker is to buy an "Executor" sound effects key ring. Touted as a harmless outlet for frustrated motorists, these produce a range of novel sound effects. Inside, they have one of the speakers in question, plus a couple of LR44 mercury cells which can be handy if you have a camera or LCD watch which uses this type. You can buy these "Executor" key rings for around $3 from some supermarkets (we purchased ours from a local Flemings store) or from flea market stands. Using the newly designed PC board, this miniature speaker and a lot of patience, we were able to fit the SteamSound Simulator into the tender of a Mansfield Hobbies brass C38 model (worth over $1000 on current prices). If you have a plastic Lima C38 locomotive, the job is much easier since the tender does not have an internal "slope sheet". Locomotives with larger tenders will be proportionately easier to do. Circuit description TO TRACK BRIDGE RECTIFIER VOLTAGE REGULATOR DIODE MODULATOR +12V WHITE NOISE SOURCE Fig.1: block diagram of the SteamSound Simulator Mk.11. The speed information is derived from the track & this controls the frequency of a sawtooth oscillator. This sawtooth oscillator controls a diode modulator which in turn amplitude modulates a white noise source. The resulting signal is then amplified & fed to a loudspeaker to produce the "chuffing" sound. Since the circuit design has changed so much, we'll start at the beginning rather than hark back to the previous article in the April 1991 issue of SILICON CHIP. The block diagram ofFig.1 has been reproduced but note that many of the components on the circuit which related to the various blocks have been changed. Now refer to the circuit diagram of Fig.2. As before the circuit is priOCT0BER1991 33 33 16V~Y_! 0.1 I spffKER 1on! -:- -:- Ra : 1M (SELECT ON TEST) Rb : 50k (SELECT D°N TEST) ~ B 1N<at>ouT EOc VIEWED FROM BELOW -:- STEAMSOUND SIMULATOR Mk.11 Fig.2: the circuit of the SteamSound Simulator is based mainly on an LM324 quad op amp IC. Diodes D1 -D4 rectify the track voltage & this controls the frequency of the sawtooth oscillator which is based on Q2 & ICtb. This sawtooth oscillator in turn controls diode modulator D8. Qt is the white noise source. Its output is fed to ICla where it is amplitude modulated by D8 to produce the "chuffing" sound. The output ofICta is then amplified & fed to the loudspeaker. marily intended for use with the pulse width modulated "Railpower" controller published in the April and May 1988 issues of SILICON CHIP. However, it can be adapted to most train controllers. Diodes D1-D4 full wave rectify the pulsed track voltage to produce positive DC voltage puls es. These are then coupled via diode D5 to a 7805 3terminal regulator which has a 4. 7V zener diode connected to its GND terminal. This effectively increases the regulator's output voltage to +9. 7V (nominal). This rail directly provides power for the audio output transistors (Q3 & Q4) and is also decoupled using a 2200 resistor and 47µF capacitor to provide power for the smallsignal circuitry (Qi, QZ & IC1). The positive-going pulses from the bridge rectifier are also fed to a network consisting of five resistors, a 0. lµF capacitor and diode D6 . The purpose of this network is to extract and filter the loco motor's back-EMF from the track voltage. Diode D6 is crucial to this functi on because it discharges the 0. lµF capacitor in between 34 SILICON CHIP track pulses, down to the level of the back-EMF. Transistor QZ inverts the track voltage signal and feeds it to a filter network consisting of resistor Rb and a 2.ZµF capacitor. As well as its filtering function, these components form part of the timing network for the sawtooth oscillator based on IClb. Squarewave oscillator IClb is 1/4 of an LM324 quad op amp, connected as a standard Schmitt trigger squarewave oscillator but with the voltage derived from QZ setting its frequency. It thus acts as a voltage-controlled oscillator or VCO. Diode D7, connected in the negative feedback loop of the op amp, causes the output signal to be a series of short pulses. The lower the voltage at QZ's collector, the higher is the output frequency. Since the voltage at QZ's collector is inversely proportional to the loco motor's back EMF, the oscillator speeds up as the train speed increases. The waveform across the 2.ZµF capacitor is sawtooth shaped, and this matches the waveform of a real "chuff" amazingly well. This signal is then fed to the anode of diode D8 via 2 70kQ and 330kQ resistors. The 0.lµF capacitor at the junction of these two resistors is used to filter the waveform and to prevent "clicks" in the output. D8 is the diode modulator stage depicted in Fig. l. Its cathode is connected to a voltage divider (150kQ & 270kQ) which sets the bias to about 3.3V. This provides us with a preset level so that we don't get too much steam and not enough "chuff". The 0.lµF capacitor on DB's cathode provides a low -impedance· AC path to ground, so that we get maximum effect from the modulation. Whenever the DC level of the sawtooth waveform rises above 3.3 volts, the diode begins to turn on and this decreases its AC impedance . The 0.lµF capacitor at DB's anode thus sees a progressively lower impedance to g:r.ound as the voltage across D8 increases. Because op amp ICla is connected as a non-inverting amplifier, these impedance variations directly control its gain. If the impedance goes down, the gain goes up. Conversely, if the impedance goes up, the gain goes down. Thus, D8 modulates the gain of ICla to provide the "chuffing" effect. PARTS LIST 1 PC board, code SC09110911, 114 x 29mm 1 miniature speaker (Jaycar Cat AS-3002; see text) Semiconductors 1 LM324N quad op amp (IC1) 1 78L05 +5V 100mA regulator 2 BC548 NPN transistors (01,02) 1 BC337 NPN transistor (03) 1 BC327 PNP transistor (04) 1 4. 7V zener diode (ZD1) 6 1N4004 power diod~s (D1 -D6) 2 1N914 signal diodes (D7-D8) This view shows the completed SteamSound Simulator board, before it was cut into two halves for mounting in the tender. The loco, by the way, is a Mansfield Hobbies brass C38 model and is worth over $1000. ~ ~-o~ 0~ [®- 2C)F .:·;."';~.: C!llil. ·1~1 i a1.•10n &si -I~~ . I -~3e-J lffEI~(!) I 0~ D)&--A-~~ost ~,(oTh T O 02A<at>D4A<at>-\..!:1/©zo, I ~i· .,(. cl)~~ L _ ·-Gs 1a os . (I) 110k (!l A(i)o · ~Q2 68 ~ io"' . ~tlji;,i1~ <at> . ~ . ~ _-. · sii ,~Y.;:....:... .Q, - ~~ . l •0 .1•!.,...-!-,-SPEAKER · r'tl~[-o.11t•IA,ri,, ~ ~ o~Q~t. ~--· ~ _ ~ ~ ~·-GJ~ N _ _, -_ ~ 04C)~3uF -03 ______:L_J N FROM TRACK Fig.3: to save space, the prototype used Philips MRS16T miniature resistors but you can also use conventional resistors mounted end-on. Check the resistor values with a multimeter before installing them on the board. Transistor Q1 is used as the white noise source. This transistor is connected as a reverse biased diode (ie, the base-emitter junction is reversed biased) and the resulting noise developed across the 47kQ resistor is coupled via a 0.1µF capacitor to pin 3 of IC1a. ICla functions as a non-inverting amplifier with modulated gain, as detailed above. The modulated output from IC1a appears at pin 1 and is direct coupled to non-inverting amplifier stage IC1c. From here, the signal is passed to pin 10 of ICld which, together with transistors Q3 & Q4, forms the output stage. Q3 & Q4 buffer the output of the op amp to provide current gain and are connected inside the feedback loop to minimise distortion. The 10Q resistor and the 0.1µF capacitor at the output form a Zobel network, which stops the circuit from oscillating. The output signal is coupled to the loudspeaker via a 33µF capacitor. The value of 33µF might seem a bit puny for a normal amplifier but since it is only handling modulated white noise, there is -very little low frequency information and so a small capacitor can be used. For the same reason (ie, no low frequencies), a small speaker can be used and still provide quite a surprising level of steam sound output. Resistor selection Two resistor values on the circuit, Ra and Rb, are not specified. They need to be selected to match the operating characteristics of the particular model loco. Ra is set so that the circuit starts "chuffing" at the exact point where the locomotive starts to move. With a careful selection of the value, you can get the circuit to work in exact unison with the loco. Rb is selected so that the maximum chuffing rate suitably matches the top speed of the locomotive. We'll dis- Capacitors 1 100µF 16VW electrolytic 1 47µF 16VW PC or tantalum electrolytic 1 33µF 16VW PC or tantalum electrolytic 1 2.2µF 16VW PC or tantalum electrolytic 9 0.1µF 5mm-pitch metallised polyester or monolithic 1 150pF ceramic Resistors (Philips MRS16T, 0.4W) 1 560kQ 2 10kQ 1 330kQ 1 5.6kQ 2 270kQ 1 4. 7kQ 2 180kQ 1 2.7kQ 1 150kQ 1 1.5kQ 3 100kQ 1 220Q 3 68kQ 1 10Q 1 47kQ Note: resistors Ra and Rb need to be selected, as described in the text. Miscellaneous Solder, hookup wire, PC pins, etc. cuss how the resistors are selected later in this article. Construction All components except for the loudspeaker are mounted on the new PC board. This is coded SC09109911 and measures 114 x 29mm. Before you start assembly of the board, carefully check the tracks for shorts or breaks. Any faults should be corrected at this stage. You have two approaches to the assembly of the board. Assuming that OCT0BER1991 35 The miniature loudspeaker is shown here sitting on top of the tender's slope sheet & could be concealed with a simulated load of coal. Despite it's small size, the loudspeaker pumps out lots of steam sound. you are going to cut the board in half, you can either cut it in half before it is assembled or after the event. We prefer the idea of cutting the board before it is assembled Special resistors We assembled our prototype boards using Philips MRS16T 0.4W resistors. These have bodies only 3.7mm long (almost half the length of a normally available resistor) and so can fit right down onto the board instead of sitting "end-on". You can assemble the board with normally available resistors but as you can see from the photos, the Philips MRS16Ts give a much more compact board. Our prototype used Wima 0. lµF capacitors which have a fixed lead spacing of 5mm. However, you can also use the even smaller O. lµF monolithics (sometimes referred to as "Skycaps" because of their blue colouring.) Don't use greencaps - they are just too big and bulky. Similarly, you can substitute tantalum capacitors for the conventional PC mount electrolytics if there is a size advantage in doing so. Make sure you follow the wiring diagram carefully because removing wrongly installed components is quite a trial, since they are so small. Use your multimeter to check the value of each resistor before it is soldered into place. After you've installed the resistors and capacitors, wire in the signal and power diodes. Make sure that the correct type is used at each position and that they are installed the right way around. Next, install the four transistors and the 78105 regulator. The pin-out diagrams, which are viewed from the underside, are on the circuit schematic (Fig.2). Finally, install the LM324 op amp IC. You can identify pin 1 of the IC by the adjacent notch (or dot) in the plastic body. Don't use a socket for the IC as it will make the PC board too bulky. Assuming that you have cut the board in half, you will need to wire the two sections together with short lengths of thin insulated hookup wire. The wire lengths should be long enough so that you can stack the two CAPACITORS 0 0 0 Value IEC Code EIA Code 0.1µF 150pF 100n 150p 104 151 RESISTOR COLOUR CODES 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 36 No. Value 4-Band Code (5%) 5-Band Code (1%) 1 1 560k.Q 330k.Q 270k.Q 180k.Q 150k.Q 100k.Q 68k.Q 47k.Q 1oi<n 5.6k.Q 4.7k.Q 2.7k.Q 1.5k.Q 220.Q 10.Q green blue yellow gold orange orange yellow gold red violet yellow gold brown grey yellow gold brown green yellow gold brown black yellow gold blue grey orange gold yellow violet orange gold brown black orange gold green blue red gold yellow violet red gold red violet red gold brown gr.een red gold red red brown gold brown black black gold green blue black orange brown orange orange black orange brown red violet black orange brown brown grey black orange brown brown green black orange brown brown black black orange brown blue grey black red brown yellow violet black red brown brown 'black black red brown green blue black brown brown yellow violet black brown brown red violet black brown brown brown green black brown brown red red black black brown brown black black gold brown 2 2 1 3 3 1 2 1 1 1 1 SILICON CHIP board halves together. With a little trial and error you will find a stacking position for two boards whereby they overlap but stack into a height of no more than 10mm. By the way, don't use single strand hookup wire (such as that used in telephone lines). It is too fragile and too easily broken. When you've finished, check the board carefully for solder splashes and dry joints. Testing & installation Before you can test and install the system, you need to select the values of Ra and Rb. To do this you will need two pots, one with a value of up to 1MQ for Ra and one between 50kQ to 100kQ for Rb. Wire the pots as variable resistors (ie, two wire connections, one to the wiper and one to an outside lug) into the positions for Ra and Rb. To test the board, connect the track leads directly to the controller and apply power with the throttle fully closed. If the overload alarm sounds, switch offimmediately and check your wiring for a short or an incorrectly installed component. If all is well, the circuit will probably make a continuous sound that simulates the noise of escaping steam. Now place your locomotive on the track and increase the throttle setting to the point where the loco just begins to move. Now adjust the Ra pot so that, when the loco begins to move, the circuit begins to chuff. You will need several tries at this until the setting of the pot is correct. Now crank open the throttle to operate the loco at the maximum desired speed. This is an important point Using the SteamSound Simulator with other train controllers OK, can you use the SteamSound SimL1lator with train controllers that simply vary the track voltage? The answer is yes but you do have to make a couple of minor modifications to the circuit. Because of the way in which simple (ie, non-pulsed) controllers work, you will not be able to power the Steam Sound Simulator directly from the rails. Instead, it will have to be powered from a separate DC supply. That in turn means that the project can no longer be mounted inside a carriage or locomotive tender, but you can mount it in a fixed position under the layout. If you're willing to accept that limitation, here are the modifications: (1 ). Disconnect the anode of D5 from the bridge rectifier and connect it instead to the positive output because with many model locos, the speed achievable with 12V DC across the track may be unrealistically high - as much as 300km/h scale speed or more in some cases. So with your loco If space is a problem, you can use tantalum capacitors instead of electrolytics. Take care with component polarity & check all part numbers carefully. of the external DC supply. This could be a 12V DC plugpack supply (which will give an output of about 16V when lightly loaded). Alternatively, you could use the supply rail to the train controller itself, provided it is in the range from 12-16V DC. (2). Delete diode D6 from the circuit. (3). Chose Ra & Rb by initially substituting pots, exactly as before. Adjust Ra so that the circuit begins to chuff when the loco starts to move, then adjust Rb for a realistic chuff rate when the loco is at maximum speed. Finally, measure the pots & substitute fixed value resistors. Note that you still must connect the SteamSound Simulator to the track via the bridge rectifier (D1-D4) to derive the necessary speed information. operating at your preferred maximum speed, adjust the Rb pot for a realistic chuff rate. In practice, the chuff modulation will be extremely rapid but still discernible. When you are happy with the pot settings for Ra and Rb, measure their resistance values with your multimeter and install the equivalent value of resistor. In some instances, you will have to install parallel combinations of resistors, with one resistor above and one resistor below the board. With tl)e resistors for Ra & Rb installed, re-check the Simulator board to make sure that it works as it should with your loco. You are now ready to install the two board halves inside the loco's tender. If you have a plastic tender, this is a relatively straightforward task although you will probably have to remove a steel weight and any internal locating lugs. SC OCT0BER1991 37 $ J8 9 RITRONAT 286- 16 (20Mhz Landmark) . Processor Max Memory Size l'.ln boardiy pe eib"sory RAM Configuratio ns 80286-16 CPU 4 Mbyte 2~, and DIP 1~2e~ Processor ~&PM?Lf~~or 80386 (Intel) ptional} ~1bd"€i6he memory contro ller Chlpset CS8281 (l~i~/ ,9Jt~f!t, )1\x/;}) 1~:g ~:~~ $495 320 bus controller 330 data butte r 1 Real Time Ck>ck Calender ~;i\~~ ~~~i~ 4Meg SIP/ Real Time Clock Calendar Battery Back-up 1 'Y ~fJ~~ ~,;?g~~b~~~ ~s..7gY1~~AM ISA Six 1 S•bil ISA slots and one 8 -bil ISA slol Architecture ~7ft~rJ~~~gts Six 16 bit and One 8 bit ~~~~abdN Rate adjustment in B1OS rprs~aJi~ H_ard Disk Boot Secto r VIRUS Protect ion RAM Configurations This bOa rd is extreme ly versatile and inte rnally very Inte lligent. 1'~aJ~~et8 nauthorised pe rsons using your system 2 The speed swilchino can be done by hardware (physical swilchl or by software (keybOard) . Suppo~ pi EM_S ~ lull~ LIM 4.0 for the lull memory maximum 0116 Moy,e . ~~f.1~ ~,~~l/sdy Insta led by !he careful electronics hobbisl in under 1 Hour. ~i~t~r~~ ~\3cm Designed to coi1orm to FCC Class B requirement s RAM Configurations f f,~g~ b~ 0 J ~~;equired : T laf bank) SIMM 2 Mbyle 41256 by 8 2 banks) SI MM 1 gy; ~MM 12 M~yte X10 D by 12 banks! SIMM 16 Mbyte 41 000 by 16 {4 ba nks SI MM ; ~gyt: 1~~\i~~=~-,~~o8~Y lo!towing :• :~ggg 1g~ik~ d This boaro is extremely versatile uses any version o f MS-DOS above 3.0, ~r;~,x;a~~X(~~:ia1{1 sl~ a~a~~ ~~~~e~\ a~(e~~mpuler buff reall y need s lo go. Jusl lollow a lew basic n..,les SJJCh !or s1a'1c precautions and component allignment Set up the menu driven CMOS RAM as directed in the user manual and you will have a prolessional ~t1,8e\n, tss Jhan 1 HOUR. ~\~ EXPANDED DYNAMIC RAM RANGE Speed (ns) ' THE CHEAPEST XT TURBO ~fOTHERBOARD ON EARTH! RITRON 486-SX20 MAINBOARD Thia mighty litUe XT motherboard has eight expansion alota and uses five low coating 1MB RAM chips to provide a lull 640K memory. The ASIC chip, well known for it'• reliabiltyis al so uaed. The CPU is state of the art technology. NEC V20 running at 4.7110 MHz (awichable) with zero wait statea. Size is just 208 x 161mm. •·GOOD THINGS COME IN SM ALL PACKAGES" DRAM 128K bytes 256K bytes 384K bytes 512K bytes 640K bytea 424256 X 1 424256 x 2 424256 X 3 424256 x 4 or 421000 x 4 424256 x 5 or 421000 x 4 + 424256 x 1 X18037 ... 0n Special at only $95.00 • Intel 80486sx Microprocessor • IBM, XT and AT • Direct support for the Weitek 4167 c oprocessor • Built•ln cache controller: Optional 32·KB, 64-KB, 128·KB or 256KB cache memory • Supports interleaved cache RAM for high speed CPU as well aa 80486 burst mode.• Flexible DRAM 1-32MB • Sophisticated DRAM controller • AMI BIOS with built•ln SETUP program • Support shadow RAM • Synchronous AT bus clock with programmable clock • Support fast A20 Gate & fast CPU reset to boost perfonnance of software utilizing 80486 protected mode, such as OS/2, UNIX..etc. • Eight expansion slota . Six 16 bit, Two 8-bit X18132 .................. ... ......................$1,950 SUPA VGA HIGH RESOLUTION RITRON COLOUR MONITOR This reliable & stylish monitor has been designed for Australian conditions & comes with a 3 year warranty. SPECS; 4164-10 4464-10 4464•08 41256•10 41256•08 44256•10 44256·08 1M·10 1M-08 256K X 9 1M x 9 1M x9 CRT: 14" 90 deflection, dari<•tint, non glare INPUT SIGNAL: Red, Green, Blue, and vertical synchronizatio e INPUT LEVEL: Video analog 0.7 vp-p Horizontal and vertical synchronization: TTL positive or negative CONNECTOR: D•aub 15-pin interface cable DISPLAY SIZE : 245+/•Smm x 180+/•Smm RESOLUTION (MAX): 1024 x 768 DOT PITCH : 0.28" MISCONVERGENCE: Centre: 0.3mm max, Comer: 0.5mm Max. SCANNING FREQUENCY: Horizontal 28 KHz-40KHZ Vertical :38 Hz.aSHz. X14532 ..................................................$495 No. of pins (64K X 1) (4 x 64K) (4 x 64K) (256K x 1) (256K x 1) (256K x 4) (256K x 4) (1M X 1) (1M X 1) Speed (ns) 80 80 70 1-9 $4.95 $5.95 $6.95 $4.50 $4.95 $9.98 $9.98 $13.95 $14.95 SIMMS ~ SIPPS Speed (ns) 256 X 9 80 1M x9 80 1M x9 70 ffiWOIIOOOO :1111!!!UJ • High Reaolution : 1,024 x 768 The Smart VGA Adaptor Is a VGA interface employing switching between 8/16 bit bus • SPEED ENHANCMENT The TVGA Chip, TVGA 8900C, incorporates an Intelligent sequencer with built in 32 bit interface medium for IBM PC/XT /AT or compatible system. The Smart VGA Adaptor cache delivers extreamly high speed perfori:nance in bus in terface and memory update. performs far beyond the normal VGA standard. BA RICES I ~ 1-9 $29.95 $99.00 $139.00 1-9 $29.95 $99.00 $139.00 8 BIT VGA ADAPTOR CARD • Support• 256 colours • Supporta interlaced and non-interlaced monitors • Support PC/XT/AT bus with auto X18074................................... 10+ $4.50 $5.50 $5.95 $4.00 $4.50 $9.50 $9.50 $12.95 $13.95 WORKS IN XT'S & Ars 512Kfl SUPER VGA CARD • Supports VGA monitors • Uses Trident TVGA 8900C chip only $495 100 100 80 100 80 100 80 100 80 Realtek Semi--Conduetor'a ch ips and software. It is a high per1ormance and inexpensive J99 X18071 ........................................ . 100+ $3.90 $4.90 $5.50 $3.75 $4.25 $9.00 $9.00 $11.95 $12.95 10+ $27.95 $97.00 $135.00 1·9 boxes 10+ 51/4" 51/4" 31/2" 31/2" DS/DD DS/HD DS/DD DS/HD 1-9 1 O+ 50+ 100+ 500+ $4.95 $10.50 $9.25 $18.95 $4.85 $9.90 $8.95 $18 .50 $4.75 $9.75 $8.75 $18.00 $4.60 $9.50 $8.50 $17.50 $4.50 $8.90 $7.90 $16.50 31/2"DD $19.95 3 1/2"HD $45.95 51/4"DD $14.95 5 1/4"HD $23.95 $18.95 $42.95 $12.95 $22.95 3 1/2"DD $28.50 3 1/2"HD $53.50 5 1/4"DD $22.95 5 1/4"HD $27.95 10+ $27.95 $52.50 $21.95 $26.95 1 ·9 boxes 3 1/2"DD $23.95 3 1/2"HD $39.95 51/4"DD $12.95 51/4"HD $19.95 HARD DRIVES ~ 85 MEG HARD DISK FOR AT 42 MEG HARD DISK FOR XT 18 ms ACCESS WITH IDE/FDD~~ 2YEAR CONTROLLER VOICE COIL.. .. , WARRANTY $495 28ms ACCESS WITH IDE/FDD CONTROLLER FAST STEPPER·.......... $549 • · tJ ❖ 1 ;1;m;t•1 •]<at>tf i•l;t)• 126 MEG HARD DISK FOR AT 16ms ACCESS WITH IDE/FDD WARRANTY y AR CONTROLLER VOICE COIL.. ............... $795 28 ms ACCESS WITH IDE/FDD CONTROLLER FAST STEPPER. ......... $395 Wi• 1 • 1 ❖ 1 0;<at>;J• 1 • 1 <at>;1;•l;f;)._ Cb• 1~latJ'I•]tfl=lt\•]lliM;J•1•]ffilt- 11ms ACCESS WITH IDE/FDD WARRANTY YEAR CONTROLLER VOICE COIL. ...............$449 12ms ACCESS WITH IDE/FDD y AR WARRANTY CONTROLLER VOICE COIL.. ............. $1,495 All Hard Diak capacities are formatted. IDEIFDD drives are already low level formatted ao you only have to "F DISK" to high level format them. Please note you need DOS 4.01 to format theB& to their maximum capacity as drive "C" or otherwise you will have to partition as "C", "D","E:", etc. If you have an earlier 1 O+ $22.95 $37.95 $11.95 $18.95 -----~ SHAREWARE : SOFTWARE : FROM $3.95. l ONLY AT OUR 1 NORTHCOTE STORE AND SOON AT STANMORE. OVER 1200 TITLES! DOS 5.0 UPGRADE NOW AVAILABLE ONLY $129 VGA GRAPHICS CARD (0 to 1 MEG) RITRON 486-33 MAIN BOARD • Intel 80486 Microprocessor • IBM, XT and AT • Direct support for the Weitek 4167 coprocessor • Built~n cache controller: Optional 32·KB, 64·KB, 128·KB or 256KB cache memory • Supports interleaved cache RAM for high speed CPU as well aa 80486 burst mode.• Flexible DRAM 1-32MB • Sophisticated DRAM controller • AMI BIOS with built~n SETUP program • Support shadow RAM • Synchronous AT bus clock with programmable clock • Support faat A20 Gate & fast CPU reset to boost performence of software utilizing 80486 protected mode, auch as OS/2, UNIX.•etc. • Eight expansion alota • Six 16 bit, Two 8•bit X18131 ..........................................................$2,450 c[·~ 3 1/2" DRIVE KIT. - Y.E DATA 3.5" 1.44/720/360 DRIVE ::~::':~;~n~d~;~~et • Cable adapter r-~ • Floppy diak controller card which controls 1.44/720/360 drives ~ • Complete Instructions to Install a 3.5.. In your existing computer. Enjoy the higher density & easy handling of 3,5" floppy diaketteal C11915 ...................$295 ..: :·:-, -- - ·:. r - . -_ . _-;::-~,~. ~-~· .. ~ Thie new VGA Graphics Adapter worb with your IBM PC/XT, PC/AT or compatible ayatem and high.resolution colour monitor to bring you sharp resolution, splendid colour and functions and features far beyond the VGA standard. Nothing aurpaasea the VGA Graphics Adapter when It cornea to high reaolution graphical Thia card has the ability to produce 256 coloura out of 256K In both 640 x 400 and 1024 x 768 resolutions. Other features of this card include: • DIP Switchea • DB-15 connector. For analog monitor• • DB-9 connector. For TTL monitora • Video BIOS: Basic Input/Output System • TVGA 8900Chip: VGA Graphics Chip • Edge connector: For IBMPC/XT, PC/AT and compatibles • Video DRAM: up to 1MB • Usea 44256-80 chipe • Feature connector : For special applications X18072 VGA CARD 16 BIT NO RAM ( EXP TO 1M)....... - - X18073 VGA CARD 16 BIT 250K (EXP TO lM) ........................................................$169 X18074 VGA CARD 16 BIT 512K (EXP TO lM)..•........•••.•.••••....................•..........••.•.$199 X18076 VGA CARD 16 BIT (1 MEG) ...... ................................................................ .....$229 MATH CO-PROCESSOR SPECIALS 80287XL. .. replaces 80287-6-80287-880287-10 .............. $295 80387DX-33............................ • ............................. $595 • 9o397SX• 16····· .. ····················• ······· ......................$450 80387SX-20............................ .. •............................$495 LOOK! NEW CARDS " MegaRAM" Memory board 4 PORT SERIAL CARD Thla new generation memory enhanced board offers O wait atate high apeed operation. It can take up to 6MBytea of 4 x 256K or 1 x 1M DRAM chip. Up to 7 cards con be uaed together (42MB EMS). It is 100% EMS 3.2 & 4.0 compatible, and beat of all it can be uaed in an XT, AT or 386 because it ia 8 bit, 16 bit configerable. So get yourself a Mega for the price of a Mini. X18051 ...............••.............•••..••...•..•••••••••.••.••••..•..••.•..••••••.. •• •••••••••••••••• $299. 00 (Software Output cables Included.) The PE-514A haa 4 aerial ports for aaynchronoua communication. These ports can be uaed to connect .•· your PC with a aerial printer, MODEM, aerial mouse · or other aerial devices which uae an RS232C interface. The Interface la a DTE type w a male DB25P for 4 aerial port outpuL It aupporta DOS & XENIX. X18155 .........$1 ROD IRVING ELECTRONICS CITY: 48 A'BECKETT ST, MELBOURNE NORTHCOTE: 425 HIGH ST, NORTHCOTE SYDNEY: 74 PARRAMAITA RD, STANMORf. MAIL ORPER: 56 Rf.NVER RD, CLAYTON PH: PH: PH: PH: (03) (03) (02) (03) 663 489 519 S43 6151 8866 3134 7877 FAX: FAX: FAX: FAX: (03) 639 1641 AS PHONE. (02) S19 3868 (03) S43 2648 All sales tax ex&mpt orders and wholesale inquiries to : ~ITRONICS WHOLE SALE 56 Renver Road. Clay, on Phone (03) 54 32 166 13 linesI Fa, 1031 543 2648 Errors and om,ss1ons e11cepled Prices and spec1!1cahons sub1ect to change :~ n:,;;,,:r~"','.~.!~"•~'0..-.otu ~'~:.:."'; ••~,_,,$te'~:,11<lo~ ,.91te red u ~ • " T ,,.c,,n.,.. ~0•1,..,,.,SPe{1'••0-t>e•) li.i,I,..-~ 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: Building A Plasma Display; Universal Power Supply Board; Remote Chime/Doorbell ; High Performance AC Millivoltmeter, Pt.1; Discolight Light Show, Pt.2; Getting The Most Out Of Nicad Batteries; Data On Insulated Tab Triacs. 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 Speakerphone 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: D October 1988 D November 1988 D March 1989 D April 1989 D August 1989 D September 1989 D January 1990 D February 1990 D June 1990 D July 1990 D November 1990 D December 1990 D April 1991 D May 1991 D September 1991 D D D D D D D D July 1988 December 1988 May 1989 October 1989 March 1990 August 1990 January 1991 June 1991 D August 1988 D January 1989 D June 1989 D November 1989 D April 1990 D September 1990 D February 1991 D July 1991 Enclosed is my cheque/money order for $_ _ _ _ _or please debit my: Card No. '---'---'--'----'I L.. -.JI---'---'--'I I I ~I~~ Signature _ _ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _ /_ _ Name _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Street _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Suburb/town _ _ _ _ _ _ _ _ _ _ _ _ _ _ Postcode _ _ _ _ __ D Bankcard D D D D D D D D September 1988 February 1989 July 1989 December 1989 May 1990 October 1990 March 1991 August 1991 D Visa Card D Master Card $5.00 each (includes p&p) . Overseas orders add $1 each for postage. NZ orders are sent air mail. Detach and mail to: SILICON CHIP PUBLICATIONS PO BOX 139 COLLAROY BEACH NSW 2097 Or call (02) 979 5644 & quote your credit card details. Fax (02) 979 6503 l ------------------------------ - -------- I 40 SILICON CHIP Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries ; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2; PC Program Calculates Great Circle Bearings. March 1990: 6/12V Charger For Sealed LeadAcid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16Channel Mixing Desk, Pt.2; Using The UC3906 Sl:A Battery Charger IC; The Controls On A Model Aircraft. April 1990: Dual Tracking ±50V Power Supply; VOX With Delayed Audio ; Relative Field Strength Meter; 16-Channel Mixing Desk, Pt.3; Simple Service Tips For Your Microwave Oven; Model Aircraft Aerodynamics ; Active CW Filter For Weak Signal Reception . June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586); Passive Loop Antenna For AM Radios; Universal Temperature Controller; Understanding CRO Probes; LED Message Board, Pt.3; Coherent CW - A New Low Power Transmission Technique. July 1989: Exhaust Gas Monitor (Uses TGS812 Gas Sensor); Extension For The Touch-Lamp Dimmer; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; NSW 86 Class Electric Locomotives. 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 Electric Locomotives. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC 13024 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. October 1989: Introducing Remote Control; FM Radio Intercom For Motorbikes (Uses BA 1404 & 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. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY and Morse) ; Supe'r-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 . 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. 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. February 1990: 16-Channel Mixing Desk; High May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors ; The Mozzie CWT ransceiver; Waveform Generation Using A PC, Pt.3; 16-Channel Mixing Desk, Pt.4; What To Do When Your Computer Goes Bung, Pt.1 . 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. 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. 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. September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs; Power Supply For Burglar Alarms; Low-Cost 3Digit Counter Module; Voice Mail For Your Computer; Simple Shortwave Converter For The 2Metre Band; How To Make Dynamark Labels. 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. November 1990: 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. December 1990: 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. January 1991: Fast Charger For Nicad Batteries, 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. Aprll 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; The Easytune FSK Indicator For HF Transmissions; Playing With The Ansi.Sys File. 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; High-Power DC Transmission Lines. 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: Build 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 & D/A Conversion. 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 postage. When supplying photostat articles or back copies, we automatically supply any relevant Notes & Errata at no extra charge . OCT0BER1991 41 COMPUTER BITS I BY JENNIFER BONNITCHA Getting the PIF with Windows This month, we talk about the Windows Program Information File (PIF) Editor which enables you to provide special information in Windows about Non-Windows applications. This is of particular importance if you want to run an application and have Windows always look to a certain directory prior to start-up. start-up directory (especially useful for storing data files in different directories). (3). To specify a program parameter for the application (such as FW3/T to start Framework and disable the license agreement screen), or to be prompted for parameters when you start. (4). To reserve short cut key combinations - some pop-up programs require key combinations which are usually reserved for Windows. (5). For 386 machines, to give the application more memory so it can run properly or to enable it to run faster. On the Accessories window, the PIF Editor in any mode enables you to It can be equally useful in directing Windows applications. The PIF's filename usually matches that of the corresponding application, so it is easy to locate. Other uses include providing the application's executable file name. If Windows can't find a particular PIF, then it assumes the standard settings that the Non-Windows application utilises. Note that most applications still run properly using the standard settings. What can a PIF do? Why would you want to change the PIF? Several reasons spring to mind: (1). To change the application's pathname. (2). To change the application's File Mode Help I .S,tart-up Directory: I I I I '{ideo Mode: <at> Text Memory Requirements: KB f!equired XMS Memory: KB Re_guired frogram Filename: Window I.itle: Qptional Parameters: Directly M odilieo: D I I I 0 Graphics/Multiple Text I128 I EJ 0 CDM1 0 0 COMZ O COM! D No Screen !;_xchange KB Limit COM_J_ EJ D _!S,eyboard Prevent Program S!!ilch 1:8:1 .!;_lose Window on E xii Reserve Shortey! Keys: 42 □ · Alt+Tab D Alt+Esc D 0 SILICON CHIP PrtSc Alt+PrtSc D Ctrl+Esc Fig.1: the PIF Editor dialog box is brought up by double-clicking on PIF Editor in the Accessories window. After that, it's simply a matter of filling in each section & then saving the file. make permanent changes to an application's PIF. And don't worry if the application doesn't have a PIF; the PIF Editor lets you create one! You can run an application directly from its PIF just as you can from the application's .EXE file. The PIF can be added to a Program Group, just as you would add an application. You can run an application directly from a PIF - one advantage is that you can then have several PIFs for a single application to cover various situations. Remember that most applications don't need a PIF since, they run properly on their own using the standard settings. If an application doe; n't run properly or doesn't run in the way you want it to, a PIF could be the answer. How do the PIFs get there in the first place? (1). Setup might create a PIF. (2). The application may come with its own predefined PIF. (3). You can create a PIF using the PIF Editor. During Setup, Windows scans for Non-Windows Applications, then automatically creates and installs a predefined PIF for that application in your Windows directory. Some applications even come with their own PIFs. Changing PIFs Open the Accessories window, then choose the PIF Editor. Each PIF may contain options for Standard or 386 Enhanced mode of operation; the Editor automatically displays the correct options for the current mode. Fig.1 shows the Dialog Box for Standard mode. Program Filename: Type the pathname of the file that starts the application. Most applications use either the .COM or .EXE extension. The filename could also be a batch (.BAT) OMSPEC=C:\DOS\COMMAND.COM IFY OFF C:\ALDUS;C:\PM4; C:\PM; C:\WINDOWS;C:\DOS;C:\UTIL;C:\DTP; TEMP=C:\TEMP OLPATH=96PATH96 MPTSPSG mono SHELL ♦ ♦ Fig.2: double clicking on the Sysedit icon brings up the System Configuration Editor, which automatically loads the WIN.INI, SYSTEM.IN!, AUTOEXEC.BAT and CONFIG.SYS files. Each file can then be edited & saved in the normal way. file if you want to set several operating conditions prior to starting the application. Window Title: This is optional but recommended, as it assists with identification of the PIF file for later reference. If you leave the title blank, when you minimise the application, its icon title contains the application's filename without the extension. Optional Parameters: This entry is also optional. Here you select certain parameters for the application to work under - eg, a filename, letters, numbers, etc - but it must be applicable to the actual application to which it's referring. You can get Windows to prompt you for parameters by typing a question mark(?) in this box. Should you want to use parameters otherthan those specified in the PIF, choose Run from the Program Manager menu and supply the new parameters. Start-up Directory: Some applications require access to certain files in a specific directory. Although once again the entry is optional, you may specify the drive and directory that · contains the application file. This could be useful in a Non-Windows application where you store the data files in a separate directory. Video Mode: The Text and Graphics/Multiple Text modes refer to the application's actual display on the screen when running. Windows gets a certain amount of memory according to these option settings. Text mode suggests to Windows that the application will run only in normal text mode. This option uses the least amount of memory, therefore making the most of the memory available to the application. Graphics/Multiple Text mode suggests to Windows that the application has capabilities of running a graphical display. This option requires more memory access, however it does ensure that enough video memory will be available when you switch between modes - Lotus 1-2-3 Rel 3 will display graphs and text, for example. Memory requirements Reference will need to be made to the application manual to find out how much free memory is required to execute the program. In general, leave the setting at 128Kb as Windows will give the application all available con- ventional memory when you start it. The number simply indicates the minimum required before Windows even tries to start the application and does not limit how much conventional memory it receives. For Kb Required and Kb Desired, a setting of -1 tells Windows to give the application all available conventional memory and as much memory as possible, up to the maximum of 640Kb respectively. XMS Memory: These options tell Windows how much extended memory to give to an application. Few applications use extended memory (although Lotus 1-2-3 Rel 3 does), so you can usually leave these options at their standard. Directly Modifies: This selection informs Windows that the application will use certain resources in a way that prevents other applications sharing the same resource. Some communications applications take control over the COM port they are using, denying access to other applications. Using this switch would guard against garbled or lost data. No Screen Exchange: This option, when selected, prevents the copying of information to Windows Clipboard using the Print Screen key. One advantage in selecting the option is that OCT0BER1991 43 .Eile ~windows] load= run = Beep=yes Spooler=no HullPort=Hone deuice=PostScript Printer,PSCRIPT,LPT1: BorderWidth=3 KeyboardSpeed=31 CursorBlinkRate=S30 DoubleClickSpeed=452 Prograrns=corn exe bat pif Documents= DeuiceHotSelectedTirneout=15 TransrnissionRetryTirneout=45 swapdisk= [Desktop] Pattern=(Hone) Wallpaper=gray.brnp TileWallpaper=1 GridGr anulari ty= o IconSpacing=101l Fig.3: section of a typical WIN.IN! file, showing its general format. This file contains all the information that defines the Windows environment. 44 SILICON CHIP . .!:!elp + + it conserves memory - the effect is similar to Reserve Shortcut Keys options. Prevent Program Switch: This is another method for conserving memory, however it prevents program switching. You must quit the application then start another, but this minimises the benefit of Windows. Close Window on Exit: Automatically closes the applications window on exit and returns you to Windows, rather than leaving the information on the screen. Reserve Shortcut Keys: Selecting one or more of these key combinations will tell Windows to ignore the specified key combination when the application is running. As the key combination you may use in the application may also perform a function within Windows, by reserving the combination Windows will ignore it while the application is running. Additional PIF settings for 386 Enhanced mode include the ability to display an application in either Full Screen or Windowed mode with Background or Exclusive execution, Multitasking, Memory, Display and Other options such as Allow Fast Paste. The PIF Editor has context-sensitive help for its parameter fields and it issues warnings if you select potentially dangerous settings (phew!) . ~earch di s play.dru=Radius TPD/PC 19-Inch Display network.dru =Hetwork not ins t alled language.dll=English (International) [Extensions] cal=calendar . exe A.cal crd=cardfile.exe A.crd + fdit [boot] 286grabber=ugacolor.gr2 386grabber=uga.gr3 fixedfon.fon=ugafix.fon oernfonts.fon=ugaoern.fon fonts.fon=ugasys.fon display.dru=tpd19 . dru shell=progrnan.exe network.dru= language.dll=langeng.dll cornrn.dru=cornrn.dru sound.dru=sound.dru rnouse.dru=rnouse.dru keyboard.dru=keyboard . dru systern.dru=atrnsys.dru atrn.systern.dru=systern.dru [keyboard] subtype= type=4 oernansi.bin = keyboard . dll= [boot.description] + + + Fig.4: the SYSTEM.IN! file primarily contains settings that allow you to customise Windows to meet your system's hardware needs. Applications requiring the PIFs can also be used in the WIN.IN! file to automatically load an application. Initialisation files Modifying initialisation files allows you to automatically load and/or run applications while Windows starts. The files that can be modified include the WIN.IN! and SYSTEM.IN! files . You can edit these files with a text editor such as the notepad program. Perhaps a better option is the SYSEDIT.EXE utility program that accompanies Windows. You can easily add the program to the Applications program group by creating a new program item, as follows: (1). Maximise the Program Manager and make sure the Windows Applications program group is active. (2). Choose File New Program Item OK. (3). Choose Browse then double click on the System Directory. (4) . Double click on SYSEDIT.EXE then choose OK. The Sysedit icon now appears in the Windows Applications program group. This text editor automatically loads the WIN.IN! , SYSTEM. IN!, AUT0EXEC.BAT and C0NFIG.SYS files when activated (see Fig.2). Each of the files may be printed for further reference , although it is the WIN.IN! and SYSTEM.IN! files which are of the most interest. If you are going to edit the INI files, make sure you have a backup copy of the files before making any changes - just to be on the safe side! One of the advantages of modifying the INI fil es is the amount of time you can save by having Windows launch frequently used applications automatically at start-up , displaying them as icons, in windows or full screen. Win.Ini The WIN.IN! file contains information that defines the Windows environment. Windows and Windows Applications can use the information in the WIN.IN! file as you configure it to meet your needs and preferences. Generally the file has the following format: [Section Name] Keyname=value Section name is the name of a section; sections are used to break settings into logical groups. The enclosing brackets are required and the left bracket must be in the leftmost column on the screen. The Keyname=value statement defines the value of each string. A keyname is the name of a setting. It must be immediately followed by an equals continued on page 96 t:LECT RON ICS ELECTRON ICS ELECTRONICS ELECTRONICS EcECTROI\ ICS ELECTPr'l~11r c:: J/\YC.A.R ELECTHONIC~ J A 'd ,., Ah i:.._.tL, I hUI\J l l.,0 J A yi...,,-u -, JAYCAR J AY C AR JA\'CA.R J AYCA R ELECTRO"ICS cLFCTRO"C.S ELECTR01'. ICS tLECTRO", ICS .I AYCCAR 1;\ i C ,\R a,WC,\H J ,WC AF, FI FC -RON ICS F cFC TRONIC S ELEC TRO ,~ ICS i:LEC TRONIC S lt>v r· c. o i:: 1 i: r T o nr--11r.s I A ',Ct.R FI F(;TRONIC:S J AYCAR J AYCAR J AYCAR J AYCAR ,IAY\,AR LrCTR01'.IC S L. [ CTRON ICS 1. L CTRONICS LECTRON ICS LECTRON ICS .IA YCAR .I AYC ,\R J A 'r CAf! J A\ CAR JAYC/1R ELECTRO NICS EL[CH10N ICS ~:U:Cl fl O NIC S c L[CTR ONICS ELEC l RON ICS J,\ YC/1H J AY C A,1 J r.. YC AR a AYCAR J AYC/,R LECT RON !C S U.:.C TRO N IC S L~C TRO NIC S LEC TRO/\.IC S .... EC TRONIC S J A '1' Ct'\,C! JN, C:AR JA YC M ..'l J/\'i'CAR F Lf-- C: TR (; f\!IC' ELFC ~ PO i\l CS ELFC-iR CJNIL~J FL_ f- C1f~Ol'!ICS J,\'1'CAR EL t. .: cr n o NIC ~ ,\-, C /,f l ,J,\'fCAH J1'1· (;/, H .J ,\ '. CNi J/,v r: AF~ l : ( ,..I<. l; ' ii ~ Lt- i.; 7 qu•,: 1~·,~~ YC f: LFC Tfff'iNU ,' ' I • C h r~u-:...;THC' \ IC', J ··<; f ~ [Li Cl f~i')'\ilC:, ! ; ( ...-HY'.i1C, ,1 J • f J1 I ~ .·c, P ~'~, r- [ UNBELIEVABLE CAR ALARM BARGAINS REMOTE CONTROL CAR ALARM WITH DRIVERS DOOR CENTRAL LOCKING 'idi1'• $179.50 SIREN OPTIONS: You will require one of the following: Normal siren horn Cat LA-8908 $19.95 Backup battery siren horn Cat LA-8910 $49.95 REMOTE CONTROL CAR ALARM WITH 4 DOOR CENTRAL LOCKING " r n ·, c I /i'. '' .IL, 1 H(J''llC- ;,, ,, r; "RO '\ i\, H(",,IC: Rry-,.. 1(,.' i~O\Jlf: · H:)t .l C ' -i; c , ,1c· f1()'\1I(:'. fl() '-. IC' / H. ', I ' H('l'\'C' H(J~~ir ' W)r.~:c RO ',,C'. ·Rnl'il C ' RO"-J ICc H: ' . :C( r~Oi !I C~ H(')"J I('< .cio~:c, RCJ : !ICc hQ.\lC.c 11(_ \iiC[ r,•·)~. :c~ H':J r"':c~ RG I. IC' R:J'.\iiC' SIREN OPTIONS: You will require one of the following: Normal siren horn Cat LA-8908 $19.95 Backup battery siren horn Cat LA-8910 $49,95 H'..H .IC~ Hr)~ :iC:HO', :Ct r HJ1Ct $119 50 SAVE OVER $50 OVER OTHER SYSTEM i SIREN OPTIONS: You will require one of the following: Normal siren horn Cat LA-8908 $19.95 Backup battery siren horn Cat LA-8910 $49.95 d::} SWANN SWITCH 00&<at>~~©© ELECTR ELECTR We have purchased the entire slacks of some Swann switches. These are lellovers from manufaclurlng runs, or cancelled orders elc. We ELECTR ELECTR Cat Sarles Description Price Cat series Description Price ELECTR cL ECTR SK0930 41 SPST 240V ilium 10A SK0950 50 DPDT 240V 15A black ELECTR 41 SPST 240V 10A ilium SK0951 50 SPOT c/off grey 240V SA ELE CTR 41 SPST 240V 10A brown SK0952 50 SPST 240V 15A black/red ELECTR ELECTR 41 SPST 240V 1OA beige SK0953 50 SPDT 240V SA c/ofl black ELECTF. 41 SPST 240V 10A grey SK0954 50 SPST 240V 15A blk/Hhile ELECTR ELECTR 40 SPST 240V 10A black.Nlh SK0955 50 DPST 240V ilium red ELE CTR 40 SPST 240V 10A blk/blk SK0960 51 SPST 240V 10Awhile ELECTR ELE CTR ELECTR ELECTR ELECTR ELECTR ELECTR ELECTR ELE CTR ELE CTR ELECTR 50 SERIES ELECTR ELECTR ELEC TP ELECTR ,::i IC JA tlt. . H I 'b A Y LAH t l tV I HU N! L,.::, J AY L, A H t: Lt: l.,IHU l'J ll, W JAY L, A H t: Lt:L, IM'UNIV U ELECTRONI CS J AYCAR ELECTR O NICS J AYC AR ELE CT RO NIC S J AY CAR ELECTR ONICS JAYC AR ELECTRONICS J AYCAR ELECTRONICS ELECTRONICS JAYCAR ELECTR ONI CS J AY C AR ELEC TRO NICS J AYCAR ELECTRONICS JAYCAR E'LEC TR ON ICS J AYCAR FLFCTRONICS :ELECTRONICS JAYCAR ELECTRONICS JAY C AR ELECTRON IC S JAYCAR ELECTR ONICS J AYC AR ELE CTR ON ICS JAYCAR ELECTRON ICS ELECTRONICS J AYCAR ELECTRONICS J AYC AR ELECTRON ICS JAYCAR ELECT RO NICS JA YCAR ELECTR ONICS J AYC AR ELECTRON ICS ELECTRONICS J AYCAR ELECTRONICS J AYCAR ELECTRON ICS J AYCAR ELECTRONICS J AY CAR ELEC TR ON ICS J AY~ A~ ~L~~ ~~ ~~ I ~ ~ 2.95 2.95 1.50 1.50 1.50 1.50 1.95 rH, 1' \JI(' ! H(":11 ~ All this for only $269.50 4 DOOR CENTRAL LOCKING ALL THIS FOR ONLY $129.50 l, ~,, '1\j(; ('TP· ,'.. IC ELECl r ELECTF ELEC FF ELECTF ELEC TF In lhe last few months we have brought you some amazing car alarm bargains. These ELECTF Included the Vandalert remote V40 and the V80 with backup ballery for $169. The way these ELE CH alarms sold out wllhln about 2weeks showed us that car alarms would be part of our product ELE CTF range provided the price Is right. Wllh this crlleria In mind we wenl shopping for quality car ELECTF This system uses lhe same electronic black box as lhe alarm above (LA8900) wilh lhe addilion of acentral ELEC TF alarms. We simply had trouble believing what we found. Hi quality car alarms and central door lock acluator for drivers door and relay to suit. So when alarm Is switched on drivers door is locked, ELECTF locking unils with more features lhan the Vandalerts for about the same money as the surplus and when alarm Is switched off, drivers door Is unlocked. ELEC FF purchased Vandalerts. WHAT YOU GET • 1 black box electronic module • 2 transmitter key fobs • 1 lgnlllon out relay • 1 drivers ELEC TF ELEC TF door cenlral door lock actuator • 1 relay for central lock • 1wiring harness ELECTF CatLA8902 J ELE CTF This syslem is supplied with 2 lransmitters and each transmiller has two buttons on them ELEC Tf blue one for alarm on/off and a red one for panic. Hit the red one anylime and lhe alarm will ELECTF sound Immediately. Also lhese lransmitters have afealure thal we have only seen on very ELECT F expensive systems. They have asliding cover which covers the buttons so the alarm can't ELECTF ELE CTF accidentally be activaled by a key or coin In your pocket touching the buttons. If you have ELECTF used a remole control car alarm before you will understand how easily this can happen and ELECTF how annoying it is. The receiver and alarm eleclronlcs are housed In ablack box. ELE CTF FEATURES OF THE ALARM • Visual arming/disarming signal - alarm on: flash once, alarm ELECTF off: flash lwice • Audible arming/disarming signal - alarm on: sou1,d once, alarm off: sound ELECTF ELECTF lwice • Slarter disable: Aseparale starter disable relay is suppliei "'hich will stop lhe engine Again this system uses the same black box and has all the same features of lhe previous models but with ELEC TF from slarling when lhe alarm Is on • Emergency panic: As mer11 ,.,t1d earlier, press lhe red lhe addlllon of central locking for 4 doors. So when lhe alarm is switched on all 4 doors are locked and ELEC TF button and alarm will soung Instantly • lnstanl triggering: Siren will sound lmmedialelywhen ELECTF when alarm Is off all 4 doors are unlocked. triggered • Door, bonnet and boot lnstanl lriggerlng • lgnlllon key switch triggering when ELEC TF WHAT YOU GET • 1 black box electronic module • 2 transmlller key fobs • 1 Ignition cul oul relay • 4 alarm Is on lhe engine cannot be slarted by lhe Ignition key • Alarm lrlggered lndlcallon: ELECTF cenlral door locking actuators • 1 relay for cenlral lock • 1 wiring harness. ELECT R Siren sounds and llghls flash slmullaneously when alarm Is lrlggered • Ignition key on Cal LA-8905 ELE CTR prolecllon: Alarm cannot be swilched on/of when ignition Is on • Manual override syslem: ELEC TR Alarm can be switched off manually if radio key is lost • Improper seal warning: If a door is ELECTR not closed when alarm Is swilched on, siren will sound immediately • Direcl line oulpul: f LEC TR Build In negalive outpul for connection of alarm sensor, ullrasonics etc • Interior lighl delay EL ECTR ELECTR circuit: Will accommodate cars wilh delays on their interior lights • Dashboard lighl: ELEcCTR Supplied with ayellow LED to visually show that an alarm Is fitted • Choice of sirens = LECTR available: Alarm Is sold without asiren and there is achoice of normal siren, or back up cL ECTR batlery siren for grealer security • Can be used lo operate central door locking thal Is already "LECT R Installed with negative output (our LR8830 4 door kll) • Supplied wilh Installation ELECT R A new addllion to our range of central door locking products. you could say lhat lhls Is an economy sel, ELECTF< Instructions. because II cannol be wireless controlled and there Is only one master conlrol which Is for lhe drivers door. ELECTR WHAT YOU GET• 1 black box electronic module wilh all lhe above features • 2 transmitler The fronl seat passenger door is aslave as is the rear door units. Supplied wilh relay, wiring harness and ELECTR key fobs • 1 ignition cut oul relay all hardware. ELECTR Cat LA-8900 Cat LR-8850 • ELECTR ELECTR j " LECTR cLFCTR ELECTR I ': LECTR ELE CTR ELECTR E.._ !:CTR ELECTR EL FCTR ELEC TR ELEC TR ::.Ll:::C TR ELEC TR ELECTR ELECTR ELEC TR ELECTR ELECTR ELECTR ELE CTR ELECTR ELECTR ELECTR ELECTR ELECTn ELECTR ELECrn Pictured: Remote controls ELECTR l •- - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; , ; ; ; , , ; . ; ; . , . . ......__,...;...;;..,...........................;,;;;,,.,.,..,;;;;;;;;.;;;.;..;;,;,,;,;;,.._ _ _ I REMOTE CONTROL CAR ALARM i1, '\JI[ ! ' ! 1< 4.50 2.50 3.50 2.95 3.50 4.95 2.50 series 51 53 21 23 82 82 475 P(l t, ;C!: W)t,iiC~ Hn~. I(:~ Pr:r~IL~ P'.-~ ' JIC. H(T.,C;<, ;r·, , il Cf i''>r-- 1c, f·./-.IC~ 1: H· ,I('• l • ,; '.·il(,1... f, ··r .!C. J.'; ·,1:;• H'.J ',JICS f,'r)~J ICt f·:,_:iiC H ')'JIC~ rr )' ,ir,~. fl' "JI(.:· :1, "i ' JIC' l•·:)• .:c:RON ICS RO :-.J ICS RON IC~ RU NJ(:~, HllN IC:..i ROl ~I CS 110'\,CS ROt\ilCS can offer these at far below normal prices. Cat SK0961 SK0965 SK0920 SK0925 SK0970 SK0971 ST0598 H1·1 1.1C::~ Description SPST 240V 10A beige DPDT 240V 10A black DPST 240V 4A while SPST 12V LED ilium DPDT c/off 240V 16A while DPDT ill um 240V 16Awhile SPST 12V ilium 10A toggle Price R~Jt\J ICS R'.)\J ICS F1 0N IC.:n(JNIC.S f.t~) : ;1C~, RO \ ICS H') '<ICS n :'"~IC~, 1.95 4.50 1.95 3.50 2.50 3.95 2.95 1, c, 1✓1cs F\ Oh!ICS RONICS RON ICS RON ICS RCJN IC:-i 11[)NICS RON ICS RON ICS RON ICS HO\IICf; l lllNICc' f1ON IC~ RO'\I CS RO"liCS I ~~~ \:JJ LEDSPOT 23 SERIES 82 SERIES • ,i • RQ\.JICS HO \II CS EcECTRON ICS tL~ C TF10NICS ELECTRC,\ ICc, ELE CT RONI CS ELE C TR ONICS J KTV Kn L e '-., 1 nVl\1 11..., .::;i J f-\ T GHn t:LCU I r. u1 -i1 1..,0 .JM, v M,, L Ll-v . JA YCAR JA YCAR JAYCAR J AYC AR JAY~ A~ LECTRON1cs LECTRONIC S LECTRONICS LE CTRONICS LE CTRON ICS J AYCA R JAYCAR J AYCA R JA YCA R JAYCAR ELEC TRONICS ELECTRONIC S ~L ECTRONIC S ELECTRON ICS ELECTRON ICS JA, CAR JAYCAR JAYCAR J AYCAR JAYCAR ~o:~rc -10'.IC ,o, c 1 ,O'IIC -1O'\JIC' 01,IC' o,,c: ONrc, ONrc, O'lrC: 0"-IC' ONIC' QNIC: ON IC: O'l:C O'JIC: o•, c. o·.c, ~Q\iiC~ 1·r:AH '·( AR 1c::,H CCAH iCAH YC,..\H ',C,-\H YCAH YC/\f ·,'CM, YCM, YCl..,H YCi\H · YC:,-\f1 \CA'-, 'r'CAfi (C;..q 1Ct..G r'CAt; rc;, i, i.-l ..•\Fi YCAH YCAH YCAH YC;\R YC,\fl YCAfl ✓ CAfl 'tC1'..H , CAI< l'C /1.R ,c::i:.. r1 )r; ,,.n . , ,\H L,,\l l 1 ,C/,H ,'CAH TCi\!{ T·c,:..n 1CAH ,·~:/\H · ChH 1'C/\P 1l ,\f-{ CAR rCAR iCAR fCf,H iC,\H I C,\tl ·C•\R 1CAH 1 CAR ✓ CAR. AR1412 AR1416 AR1420 AR1425 AA2050 AA2090 AS3050 D90 TDK pkt 3 tapes AD60 TDK pkt 2 tapes AD90 TDK pkt 2 tapes SA90 TDK pkt 2 tapes Walkman speakers (PR) Lockdown car antenna Redford stereo ceiling spkr kit AM4206 Mic mixer 6 channel BS0416 Book: Macintosh Prag BS0418 Book: Computer Aided Logic Design BS0430 Book: Understanding CAD/CAM BS0490 Book: Musical Applic Micros BS0510 Book: IC Users Casebk BS0514 Book: Audio IC Op Amp Applic BS0534 Book: Design of PLL's BS0602 Book: Microcomp for Business BS0739 Book: Best - Lotus 1-2-3 BH0902 Book: IBM PC/XT User BH0904 Book: Electric Circuits BP1208 Book: Home Recordings Make Money BP1212 Book: Intro Digital Audio CX2613 2 Way x'over 60W 5kHz DS6000 Scanner - Roadrunner ARBBO HP0254 Bolt - 25 pcs 6BA x12mm CH HP0257 Bolt - 25 pcs 6BA x 18mm CH HP0551 No 4 x 6mm self tapper pkt 10 HP0630 Black wood screw No8 x 19mm pkt20 HP1186 lnsul staples pkt 100 HP1203 Cable tie pack 75pcs HP1210 Crimpwire connectorpkt 8 HR5210 Rack frame 6 unit HR5215 Panel set for 6 unit HR5217 Rack frame set 12 unit HR5219 Panel set for 12 unit HB5380 Black rack box see cat page 44 HB5381 Black rack box see cat page 44 HB5382 Black rack box see cat page 44 HB5383 Black rackbox see cat page 44 HB5400 High energy rack box HB54 76 84/1 ?V instr case HB6366 Bug cage for 6 bug boxes HB6370 Bug cage cover HK7730 Silver slider knob HH8506 IC heatsink ,CAR /CAR. _:. 'CAR I 'CAR I 'CAR I 'CAR I 'CAR I 'C AR I 'C AR I 'CAI, i CAR I 'CAR i 'CAR I 'CAR I 'C AR I 'CI\R I 'CAR I CAR I CAR I 'CAR I 'CAR I 'CAR I 'CAR I 'CAR I 'C AR I 'C AR I 'CAR I 'CAR I 'C AR I 'CAR I 'C AR I 'C AR I 'CAR I :;s JAYCAR :;s JAYCAR :;s JAYCAR ::;s JAYCAR ::;s JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS 11.95 7.95 10.50 13.95 9.95 8.95 7.95 4.95 6.95 8.95 4.95 3.95 99.50 59.50 149.50 99.50 39.95 20.00 44.95 20.00 34.95 16.95 59.95 39.95 22.95 15.95 34.95 19.95 24.95 14.95 19.95 44.95 47.95 69.50 12.95 24.95 29.95 39.50 17.95 7.95 17.95 9.95 7.95 4.95 399 .00 279.00 1.95 .50 2.75 1.00 .75 .10 1.95 .75 6.95 1.00 .25 3.95 1.50 149 .00 59.95 169.00 89.00 .50 110.00 35.00 129.00 59 .00 35.00 25.00 45.00 30.00 45.00 30.00 55.00 39.00 129.50 89.50 49.95 29.95 8.95 5.95 .95 .95 JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR 2.00 100 .40 .50 HH8512 T05 press on heatsink HH8540 Die cast heatsink 50mm HH8541 Die cast heatsink 75mm HG9989 Scotchcal alum red HG9990 Scotchcal plas red/white HP9520 365x210mm D/sides F/glass KA1230 Zener diode tester kit KA1635 AM/FM stereo tuner KA1710 Beepo continuity tester KA1711 TTL analogue video conv KA1714 Beat me metronome KA1715 Car brake lamp monitor KM3016 RTTY encoder KE4200 ETl5000 PA kit KC5010 Capacitance meter for DMM KC5040 Speaker phone kit KC5043 120W PNguitar amp mod KC5044 Car safety lights KC5053 Extension touch dimmer KC5054 Garbage reminder KC5061 Balance add on stereo equ KC5062 Hot canaries KC5073 Dual track power supp KC5078 PSU load protector KC5082 DC offset for DMM KC5086 DC-DC converter car KC5087 Big escape game KC5088 Fruit machine game LT3027 Indoor balun LA5062 Shock vibration module LA5128 PIR security light sensor LR8812 Power car window winders LR8834 Car door actuator - H/duty MF1030 PL 12/20VA Ferg transformer MA 1506 600R-600R encased T/f MM1512 Modem transformer bargain MM2020 Ccore T/f suit P/M 60/60 MS4020 4 outlet squeeky mains fill Ml5010 600W inverter 12-240V NA1015 W040150g spray can PP0246 RCA plug - solder less PP0247 RCA plug - rapid PS0642 F59 coax socket PA0885 RS232 surge suppressor PP1052 Canon 5 pin male line PA3588 Adaptor 6.5 man plug > 6.5 ster skt PA3597 Adaptor 6.5 ster plug > 2 x3.5 ster skt PA3650 PL259 pig> RCA skt Pl6300 84 pin PLCC skt Pl6496 22 pin IC ski w/wrap Pl6555 24 OIL IOC plug/cover Pl6558 40 OIL IOC plug/cover QM7206 BKOatabank/calc QM7210 World time credit card QM7240 Metronome - electronic RC5367 .39uf 50V ceramic cap RC5375 470pf 400V AC ceramic RE5815 4.7uf 25V RT electro RE5888 1OOuf 200V RT electro SF2237 600V AC 2A fuse for DMM ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRO'IICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .40 .75 5.95 3.95 8.95 5.95 11 .95 6.95 11 .95 6.95 14.95 4.95 16.95 9.95 599.00 399.00 19.95 12.95 49.95 22.95 29.95 17.95 24.95 14.95 29.95 14.95 499.00 450.00 27.95 14.95 89.00 69.00 72.50 49.50 29.95 10.00 14.95 9.95 24.95 14.95 17.95 9.95 24.95 14.95 239.00 199.00 17.95 8.95 39.95 22.95 149.50 99.50 34.95 18.95 26.95 16.95 3.50 2.00 14.95 5.00 69.50 39.50 239.00 189.00 46.95 26.95 34 .95 19.95 12.95 5.00 1000 5.00 79.50 49.50 269.00 189.00 639.00 499.00 3.95 2.00 1.95 .95 2.95 1.25 1.40 .20 19.95 9.95 14.95 8.95 1.95 .75 4.95 3.95 2.95 4.15 3.95 4.95 59.95 19.95 39.95 .40 .50 .40 175 8.95 1.50 1.00 .50 .40 1.00 1.50 20.00 9.95 19.95 .10 .20 .10 1.00 3.95 ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAY CAR JAYCAR JAYCAR SB2462 AA to CNiCad adaptor pkt 4 SB2464 AA to DNiCad adaptor pkt 4 SB2500 G2 watch battery SL2900 12V inspection lamp ST3005 Ar lee smart lite torch ST3010 Super torch arlec ST3015 Arlec fluro lantern ST3025 5D metal torch SY 4002 2 c/o cradle relay skt SY4004 4 c/o cradle relay skt TS1428 Hotblow tip portasol pro TS1429 Blowtorchportasol pro TH1882 6" linesman cutter/plier TH1900 Arlec supertool TH1910 Cutting discs -supertool TH1912 Engraving/milling supertool TH1920 Arlec easy etchengrav XC0101 24 hr clock movement XC0102 Backward clock movement XW0405 Arlec 7 day timer XV2060 Bosche 6 cyl rotate vane XC5092 Philips 101 keyboard XF7080 Phone/fax/modem line prot YS5520 12V Bug killer YT6600 Fax/telephone sw YT701 O Answ machine 1800 ZR1130 BR100 ZV1675 LM723 T05 ZT2315 2N3569 2L3064 TL064 2L3834 CA3100 2C4000 4000 CMOS 2C4010 4010 CMOS 2C4426 4426 2C4512 4512 2C4528 4528 2C4538 4538 2C4582 4582 2C4583 4583 2C4853 74HC157 2C4860 74HC240 2C4861 74HC241 ZC4870 74HC368 2C4896 74HC4075 2C4902 74C02 2S5033 74LS53 ZS5083 74LS83 2S5148 74LS148 2S5155 74LS155 ZS5163 74LS163 2S5191 74lS191 2S5195 74LS195 2S5196 74LS196 2S5241 74LS241 ZS2543 74LS243 2S5259 74LS259 2S5366 74LS366 ZS5854 7454 ZX7010 CI06Y1 SCR 228195 81 LS95 ZZ8197 81 LS97 2Z8198 81 LS98 ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR FLECTRONICS ELECTRONICS ELECTRON/CS cLECTRON/CS ELEC TRONICS 3.95 1.50 3.95 1.50 2.25 .50 6.95 2.95 22.95 14.95 44.95 24 .95 99.95 59.95 39.95 24.95 1.50 .50 2.50 1.00 15.95 9.95 15.95 9 95 7.95 3.95 89.95 69.95 18.95 11 .95 14.50 8.50 43.95 26.95 14.95 9.95 14.95 9.95 34.95 21 .95 49.95 29.95 99.00 59 .00 99.00 59 .00 29.95 17.95 299 .00 229 .00 79.95 59 .95 .95 .30 2.95 .95 .68 .10 5.50 1.00 4.95 2.00 .80 .20 1.25 .20 2.90 1.20 1.95 .50 175 .20 175 .20 2.90 .60 1.50 .20 1.25 .25 3.20 .30 2.75 .30 2.95 .30 .95 .20 3.95 .3b 1.00 .20 1.95 .20 3.95 .40 1.85 .40 1.60 30 1.85 30 1.85 30 2.95 30 2.20 .30 2.95 .30 2.90 30 1.25 .20 .80 .20 1.20 .40 3.20 .20 3.20 .20 3.90 .20 JAYCAR JAYCAR JAYCAR JAYCAR JAYCAh JAYCAR ! JAYCAR I JAYCAR I JAYCAR I JAYCAR i JAYCAR I JAYCAR I JAYCAR I JAYCAR I JAYCAf, I JAYCAR I JAYCAR I JAYCAR I JAYCAR i JAYCAR I JAYCAR I JAYCAR I JAYCAR I JA /CAR I ,JAYCAR I JAYCAR I JAYCAR I J.AYCAR I JA\CAR I JAYCAR I JAYCAR I JAYCAR I JAYCAR I JAYCAR I JAYCAR I JAYCAR I JAYCAR I s!A YCAR' JAYCAR I JAYCAR I .JAYCAR JAYCAR JAYCAR I JAYCAll I JAYCAH, JAYCAR JA'rCAR' .IAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .JAYCAR Jl\'/CAR JAYCAR JAYCAR JAYCAR JAYCAR JA/CAR JAYCAR .JA\CAH JAYCAR JAYCAH JAYCI\R .JAYCAf1 JAYCAH JA YC~H I JAYCAH I JA\CAH I JAY(:/l,H I JAYCAR JAYCAR JA'rCAR JA\CAR JAYCAH I I I I I 11\YCAR I JAYCAR I JAYCAR I JAYCAR I IAYCAH I IA YCAR i IA YCAR I IA\CAR I IAYCAR I IAYCAH I IAYCAR I IAYCAR I IAYCAR i IAYCAR i IAYCAR I ELECTRONICSJAYCAR I ELECTRONICSJAYCAR I ELEClRONICS JAYCAR i ELECrRONICSJAYCAR f tLECTRONICS JAYCAR f AR AR AR AR AR AR AR AR ELECTRONICS EL ECT RONICS ELECTRONIC S ELF CTRONICS ELECTRONICS ELF CTRON IC S ELECTf EL ECT A R t LEc T JAYCAR JAYCAR J AYCAR J AYCAR J AYCAR J AYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONIC S ELECTRON IC S ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRON ICS ELECTRON ICS ELE TR JAYCAR JAYCAR JAY CAR J AYCAR JAYCAR IAY !JD&W SMALL PHILIPS AR AR AR AR AR AR AR AR AR A new addilion lo our range of qualily dome lweelers. Ideal for small bookshelf speakers, or to give a new lease of life on an old syslem by replacing the old tweelers. Looks exaclly like lhe AD11610, excepl it is smaller. Texlile dome. Made in Belgium. An Specrrications: • System power 80 walls F\MS • Frequency response 330020,000 Hz• Resonant frequency 1700Hz • Magnet Weight 60 grams • Voice coil diameler 25mm \R E._EC TR \R ELEC TR \H le . te rn \ R E.~C TR \R [LE CT.9 . :~;f~~;,,fJf} i ?);~~~~~fd~ to the olher 74mm. ,' ·r:.,e:' J ; ::, · · i., ·, · diagonal Mounling holes 83mm. ':'.'.! · • • . J:;,; · .;, / .: culout65mm .,,; Cal CT-2013 , ,r,:; $22.95 Car HiFi woofer You don'I see this very often. These are 8' honeycomb woofers designed for car HIFI use. They have a metal grill over the cone, a huge 20 oz (.57kg) magnet, foam roll surround, black frame and silver honeycomb diaphragm. Power handling 35 walls rms, sensilivity 93dB, frequency response 60Hz lo 12kHz, impedance 4n. Now less than half price 1988 Arista Cat price The new moss MS-712 projects a completely harmless 2-45 gigahertz hyper frequency energy field Inside your car thal will detecl lhe slightest Intrusion. this system is unaffecled by air lurbulency or temperature fluctuatioos and eliminales false alarms. Ii can be used wilh lhe windows or sun-roof partially open, arid is ideal for all soft-top vehicles. The latest technology and variable range adjuslment allow you to set the energy field precisely lo suil your own requirements. The unit is ultra compacl measu ri ng only 85(L) x 55(W) x 221(H)mm FREE VIDEO- This unit is supplied with aVHS instructional video as well as ail wi ring and fi tt ings. The uni t has lhree wires lo connect - one lo earth, one lo positive which Is only available when lhe alarm is on, an one trigger wire. 12 monlhs warranty and a help line available. Cat LA-8922 $99.95 Car stop light Put one of these on your rear parcel shelf and avoid rear end collisions. Easy to inslaii with self adhesive rubber mounling and 2 ml cable. 12 V DC. Arisla price $13.35 CalAA-2085 $119,95 VIDEO LEAD MADNESS AV-6514 AV-6516 PL259 _., RCA ELEC TRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS TR I JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR AY AR ELECTRONICS ELECTRONICS ELECTRONICS EL ECTRONICS ELECTRONICS TRONICS JAYCAR JAYCAR JAYCAR J AYCAR JAYCAR JAYCAR ELECTR ONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELE TR NICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR Was Now $8.95 $7.95 $5.95 H UHF ANTENNA PRICES SLASHED We were sick and tired of paying loo much for anlennas. We have found our own supplier and can now reduce lhe prices by up lo 45%. Bui don'I worry, lhe new ones are imported bul so were lhe ones lhey-replaced. New everyday low prices. Wholesale enquiries: phone (02) 747-2022. Spees-Gain: 13dB, Channe ls: 21-69, Frequ: 470-862mHz, Boom: 20mm square, Overall length: 1234mm, Finish: elements and boom anodised. Cal LT-3181 Was $89,50 NOW ONLY $49 ■ 50 :g~:~ 10N,c Al lasl you can now buy black philips head chipboard screws ID mounl your speakers from Jaycar. These are very dlfflcull lo oblain. Two sizes available. Large No. 10 x 30mm Ideal for woofers ~ Pkt 20 Cal HP--0624 $3.50 ~ Pkt 200 Cal HP--0626 $27 .50 Large No. 6 x 15mm Ideal for lweelers, mid ranges, crossovers Pkt 20 Cal HP--0620 $2.95 Pkl 200 Cal HP--0622 $22.9: f \~ 43 Element ELECTRO ELECTRO ELECTRO ELECTRO ELECTRO ELECTRO ,Ot-.l l ,01' 1( ;g~:~ ~~- - a pair BNC _., PL259 PL259 _., PL259 JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR Y A, Jaycar price $49.95 AV-6512 ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONIC S ELECTRON ICS R a d a r I n t e r i O r M O Ve m e n t D et e C t O r $4.95 Cat CW-2117 Length 1.Smt Cal JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .I Car alarm breakthrough Speaker mounting Mo s s H y p e r - F re q u e n c y screws DOME TWEETER ELECT tLECT EL ECT ELf-CT ELE CT ELE CT E:L ECTF ELECT EL ECT AR ELECT AR E:L f-Cl I AR f-L f-CT AR FLF CT ELECT A,R t:: L EC T •\R ELECT AR f-Ll'CT AR ELFCl AR FLECT AR tLE:C l AR ELFC T AR ELECT AR ELEC T AR ELEC T AR E'LFC T AR ELEC T AR E: Lt C. 6-R FLFCT F i\ R l'cFCT AR I'll CT AR fLf-CT -\R H_f-Cl .\R E:LE:C T AR ELEC T AR ELECT. ;R ELECT \R f-U CTF .\f1 cLECl F >.R ELtCl \P f-LE:Cl F .\R ELF Cl F \ R EL F CTF \R Flf- ClF \R f- 1 F CTF ,R f LE C TF \R E:LrC TF ;Rf c[C TR \R ELEC TR .\R ~Lf CT R \R ELbCTR \R FLEC TP \R ELECTP. \f1 E:LECTR \R E.ECTR ELECTRONICS ELECTRONICS ELECTRONIC c ELECTRONICS ELECTRONICS T I , ~.~ 00 ~ 1 (c , , 'lONI( ~ONIC ,ONIC 'lONIC 10'-JIC 10 NIC 10"!1( 10 NIC 10 NI. 10NI•, i ON I(_ , ONIC 10N,. ~ONlt. iONIC ,ONIC 10MC 10NIC 10NIC 10NIC 10\11( 10•\IIC 10 NI C 10NIC 10 NIC II CS ii JI C~ ,J/1 II C0 ,II• !IC::; J/ l!CS 1,· ::r~~ ;: IIC(, J,· ilC~, ,I,-. 1/C::--.J/ ICc JA IC.,::, Jt- I(..'. , ,It 1.3AH 12 VOLT GELL ~---- ~-BATTERY ll3&ilXJ<at>&iD[]fJ Cat SB-2480 ~ Normally Build 'bur ·(Min IBMQ)mpatlble ~~~q, Ut:n ,tl; ~•:; $28.50 October $20 C~J JA, ELECTf ELECTf ELEC Tf ELECTf ELECTf ELECTf ELECTf ELEC Tf ELEC Tf ELECTf ELEC T! ' - ., ...,,._, ELEC rRONICS ELECTRONICS ELECTRON1CS ELECTRONICS E L~ ~_.::!"_RONICS ~- • ' '--''"' '' JAYCAR JMCAR JAYCAR JAYCAR JAYCAR . ._ '-'-'-' '' ''--'' ~,....,..., ELECTROl'.ICS ELECTRON ICS ELECTRONICS ELECTRON ICS ELECT RO NICS ..,,..,, ' v r " ' JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ,_,_._...., 1 • , ...., , ., ....,...., '-'',, '-'' " , '- '- '-'-' • , , ....,, ., ....,...., vn, vnl\ CLCv i l 1Vi "~i'v0 Jh i Vril\ Ci...CV i I \\.J i",ffv0 JM 1 VM.1' l::LCU I nUI\I IV0 .JM T VMn CLCV I nUl'HV0 JM! VMn ELECTRON ICS ELECTRONICS ELECTRON ICS ELECTRON ICS ELEC TRON ICS JAYCAR J AYCAR JAYCAR JAYCAR IAYCAB ELECTRONICS ELECTRON ICS ELECTRONICS ELECTRONICS El EC TB ON ICS JAYCAR JAYCAR JAYCAR JAYCAR I AYCAB ELECTRONICS ELECTRONICS ELECTRON ICS ELECTRONICS FI FC_'t.A()h !lrC JAYCAR JAYCAR JAYCAR JAYCAR ELECTRON ICS ELECTRONICS ELECTRONICS ELECTRON ICS 11\.YCAD C l C:CTI2Cl.h.llC'C::- JAYCAR JAYCAR JAYCAR JAYCAR ELECTfiON ICS ,JAYCAR ELECTRONICSjJAYCAR ELECTRONICS JAYCAR ELECTRONICSIJAYCAR I f\\lcoo r, cox a IC~, J. ICS J, ICS J1 ICS J• ICS J/1 ICS J/, ICS JA IC$ JA, ICS JA: ICS JA' ICS JA ICS JA, CS JA CS JA CS JA , CS JA ,CS ,JA ICS Jt CS JA CS ,IA, ELECTRONICS ELECTRONICS ELECTRON ICS ELECTRON ICS I ol'O • □ r , re J AYCAR J AYCAR JAYCAR J AYCAR CS JA, CS JA', CS JA, CS JA , CS JA\ CS JA\ CS JA, CS JA\ ICS JA\ CS J A\ CS JA \ ICS JA', IC,JA\ CLcCTRONl1 ELECTRON! ELECTRON!• ELECTRON! ELECTRON! • .==~~~---- - ,.,..~ .. U:.C I HUNICS JAYCAH !::U:C I HUNIC~ J AYCJ..\H t::L t C I HUNIL,; ~ J AYL,AH t ltL, I iiUN fl,b Jh YL, A t1 t:Lt:l, J HUNIL,~ J A YL,A r! tLtL, l H U Nll;:, J f1 YCI\H c-U LI HU M l -~) ,JA YL,AH t .t-C I HU NI( ~:._, , JM) LA H f t.1· { I Hl l f'JI ( ;~ LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECl RONI CS JAYCAR LECTRONICS JAYCAR ELE CTRONICS JAYCAR ELECTRONICS JAYCAR LECTf LECTf LECTf Transistor washers that don't LECTf require silicon grease LECTF LECT "ECTF c.ECTF · Al last you can slop using messy silicon grease. These washers are made from silicon rubber and are effective as mica and grease. .. ECTF .. ECTF Avoid mica washers Iha! crack, avoid run off, speed production LECTF assembly lime. Three sizes available including !he new T03P size -ECTF as well as T03 and T0220. Physical properties: _ECTF Colour - grey Tensile slrength - 40kg/cm' LECTF Elongation - 80%Dieleclric breakdown voltage - 4000ft).3mm LECTF LECTF Co-efficient of thermal conductance - 2.4 x 1□-' LECTF Flammability class - 94V--Oftl.3mm rrr;nJ LECTF LECTF LECTF LECTF LECTF LECTF LECTF LECTF' LECTF LECTF . Type Pack qty Price Cat LECTF LECTF HP-1150 $6.95 LECTF .. ECTP 100 $23.95 HP-1151 .. ECTR HP-1155 $2.50 .. ECTR Silicon impregnated rubber washers ' [S"T~I~<at> .. ECTR -ECTR .. ECTR .. ECTR cECTR cECTR LECTR LECTR cECTR 20 T03 TD3 T0220 T0220 T03-P T03-P 20 100 $8.95 $4.50 $14.95 20 100 HP-1156 HP-1160 ELECTRONICS JAYCAR ELf-C IRONIC:, JAYCAf, clcCTRONICS JAYCAR ELf'CTHOI\ICS .JAYC Al1 I., FCT,10NICS JA YCAf1 U I (;1 l<ONICS ELECTRONIC S JAYCAR EU'CTRONIC!J,JAYCAR ELLCTRON IC S J,WC /,R EL ECTRQf\lCt; .J,\',C AH [ .. CC THONICS JAYC AH 11 f1•·I1<C, f\ lC:>; ___ __.,__ ....... -· ----- ..... ,. · - - - - -- - .. - ..... . _ . .- _ . . , -~=~ - STUDIO 3-SSL SPEAKER KIT "THL)f'HCS -rno1J1c:::. $279 Refer Silicon Chip Aug 91. This masthead amplifier kil is easy lo build install. II will give around 18dB of gain from 40MHz lo 1GHz which Is right across !he UHF and VHF bands plus FM band (88-108MHz) as well. The Jaycar kit includes !he special 24V AC power supply. Beware of other klls which don '! supply !his. Also includes PCB, jiffy box, mas! clamp, OM 350 and all specified comP.2,nenls. Cal KC-5097 :t,44.95 $250 DIGITAL TACHO KIT Refer Silicon Chi p 1991. Al last, a high quality speaker kil al a very reasonable price using quality components. Jaycar and Silicon Chip proudly announce lhe 3-5SL 3 way speaker kil. The kil Incorporates !he magnavox 12W, 12' woofer, sealed s• midrange driver ,rnd !he fabulous Phillps AD11610/T8 dome tweeter. Power handling is 80 walls programme. Drop into any Jaycar store for a demonslralion (no! Concord). The kil is available in two parts. Part one includes !he drivers, crossovers, terminals, faders, lnnerbond, screws, cable etc. Part two includes !he two fully build black cabinets with all holes cul and speaker grill filled. Part 1: Speakers etc NEW KITS MASTHEAD AMPLIFIER cat cs-24so 11l0',ICS TftONICS THC,l'<ICS rno,IIc s TRONICS TRONICS TRONICS TRONICS THONICS TRONICS TRONICS THC"JI CS 1h i)N ICS TRON ICS Tf<ONIC:· TROtJICS . 1ROi'<1 C::: l RO ''-! CS Tfs!()f , ICf, TH01'~1CS Part 2: Cabinets cat cs-24s2 Refer Si licon Chip Aug 91. This LED digital tachometer features a 4 digil readout Iha! indicates from O-9900 RPM. II works from Kellerlng lo Hall Effect systems and with 4, 6 and 8 cylinder cars. The Jaycar kit is ashort form version, everything is supplied except !he box and Iron! panel - as we feel many conslruclors will wan! lo mount ii in !he dash. Cal KC-5 34.95 TOTAL $529 BUY BOTH TOGETHER FOR ONLY mo,:ics THCY~lCS $499 HP-1161 T f{f) \, iCS rnm.:cs TRONICS TRONICS TRO'J ICS TR: J'!ICS Tn Ot-JI CS Tf10NICS TRONICS TR Ot-.lCS TROi'JICS (Size 25 x 20mm) RON ICS BUSHES Tf10NI(;!-, rf10'\ICS =~g;= Now available, separale bags of bushes lo suit !he new silicon lmpreganled rubber washers and mica washers I HOt>,JICS -ECTR TO220 TO3 =~gi= = ~gi= . ECTR _ECTR .ECTR LECTR t ~gi~ LECTR LECTR LECTR LECTR LL~cc~RF LECTR LECTR LECTR LECTR LECTFi t~g~ LECTR LECTR LECTR LECTR - f10NICS RO,HCS $8.95 Cal HP-1166 $9.95 Cal HP-1168 TELECOM POWER SUPPLY ill&i[JJ<at>i£Jilf1] Pk! 100 Pk! 100 HlJN IC~ This is a quality power supply! 11 is 240V primary lo 48V DC al 1.5A and 75V AC 50Hz al 6V A. II is housed in a large metal ~ enclosure measuring 300(L) x 140(W) x 100(H)mm. II incorporates two transformers, fuseholder and spare fuse, 2 x 2500uf 63V can eleclros, rectifier board and two large voltage resistors. The Inputs and outputs are all screw terminal strips. These would have cos! Telecom a fortune lo be made. Due lo the enormous weigh! - we must ask mail order customers lo add an extra $5 on lop of normal p & p charges. Cal MP-3032 LOW COST 1 SY 1 A BENCHTOP SUPPLY KIT Rei: EA August 1991 This economy priced power supply fealures: • variable oulpul voltage from 2 5 lo 18V • swilchable current limiting. both voltage and current metering. The Jaycar kil includes PCB, all specified components, Scolchcal panel and meter scale. ~~g~ LECTR LECTR t~g~~ LECTR LECT t~cci~ RONICS m CNICS rRONICS H1or,Ic~ ROIJICS ReferSiliconChipAug9l Can record messages up lo 20 seconds long. Store !hem on hard or floppy disc and !hen replay !hem when you wish. The Jaycar kil indudes all specified components except !he plugpack and zippy box. The software Is available from Silicon Chip. Cal KC-5099 ROMCS I1UNI CS KON ICS 110NICS rHONICf, f<O'JICS KONICS HONICS HONICS r nONICS r R0 i\.1CS ~r,~.,cs mONICS $32.95 Speech processor kit for transceivers fil)MC~ Refer EA Sep! 91. Increase your talk power. Connects In line with existing mic, and acts as a preamp, compressor and speech filler. II so aulomalically generates a 'beep' each lime !he press lo talk bullon Is short form kil. Includes PCB, mic socket, relay and al specified components. No ~~ e~. ·"·-·-·-·~'- -..3 ~~i~ $79 95 Ro'Jics RONICS Ro NIcs I I RONICS I KON 1c::; r:g ~:g~ mo NIcs rHONIC!i mo ,:1cs [: gN:g~ rRONICS rnoNIcs ~g~g~ ~8~:~~ Grab one now at this crazy price LECTR Cal. KA-1736 ■ RONICS LEcrn rnoN1cs LECTRl l ! ! ! ! " - - - - - - - - - - - - - ~ ~ ~ ~ ~ ~ ~ - - - - - ~ ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ~ ~ ~ ~ ~ ~ ~ ~ - - - - - - - - - - - ~ ! " ' i imoN,c s t~g;~ ~-■.P"'"'li.-,,,_• ..,-.._.• ......, HEAD OFFICE POST & PACKING MAIL ORDERS MAIL ORDER VIA ONLY $35 each LECTR LECTR LEC TR LECTR t~g;~ LEcrn LECTR LECTR LECTR LECTR LECTR LECTR LECTR LECTR LECTR t~g~ ~ ~, • ·••.J••····· .,._,..,_:(.,,..._.;.,.•_...,.i.,[..._._ ' • 'ff ~ , 115Parramatta RoadConcord2137 CONCORD I■■-• ,,7.,r A rl ~ BANKSTOWN $10-$24.99 $25- $49.99 T e Iep h one (02) 7 4 7 2022 FAX (02) 744 0767 $50 - $99.99 $ 3.75 $ 4.50 $ 6.50 P.O. Box 185 Concord2137 ROAD FREIGHT FREE CALL-FOR ORDERS ONLY (008) 022 888 ANYWHERE IN AUSTRALIA ---------=□V:::EA:::$:::100::::=:::::::$8::::::.00==:!....fu:_p1_021Jkg__::_)S1_3_.so_ _ _ _ HO_TL_I_NE_(02_)7_4_71_88_8_ SYDNEY · CITY 117 York St. (02) 267 1614 PARRAMATTA $29.95 BURANDA QLD Mon-Fri 8.30 - 5.30 Thurs 8.30 pm - Sat 9 - 1 355 Church St (Cnr. Victoria Ad) (02) 683 3377 COBURG VIC Mon-Fri 9 - 5.30 Thurs 8.30 pm - Sat 9 - 4pm U Sunday 10am - 4pm MELBO RNE-CITY 115 Parramatta Ad Cnr Lloyd George Av (02) 745 3077 Mon-Fri B.30- 5.30- Sat 9.00-12 SPRINGVALE VIC 363 Hume Highway Cnr Meredith St (02) 709 2822 Mon-Fri 9 - 5.30Thurs 8.30 pm - Sat9 - 4 ADELAIDE S.A. 188 Pacific Hwy (Cnr. Bellevue Avel(02) 439 4799Mon-Fri 9 - 5.30 Thurs B.30 - Sat 9 - 4pm :LECTR ■llllilillil■ GORE HILL :LECTR :LECTR ,LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR .LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR :LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR :LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR 'LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR :LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYC.A:R ELECTRONICS JAYCAR ELECTRONICS JAYCAR :LECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR 144 Logan Ad (07) 393 0777 Mon-Fri 9 - 5.30 Thurs 8.30 - Sat 9- 4 266 Sydney Road (03) 384 1811 Mon-tri 9 - 5.30 Fri 8.30 - Sat 9 - 4 Shop 2. 45 A'Beckett St City (03) 663 2030 Mon-Fri 9 -5.30 Fri 8.30- Sat 9- 2 887-889 Springvale Road Mulgrave (03) 547 1022 Nr Cnr. Dandenong Road Mon-Fri 9 - 5.30 Fri 8.30 · Sat 9- 2 190 Wright Street (Cnr Selby Street) (08) 231 7355 Mon-Fri 9-5.30 Fri 8.30- Sat 9- 12 ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAH ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR : 6~:~~ : mo Nics moNics rHON ICS rRON ICS ~~g~:g~rRONICS rROI\IC S rRONICE rRONICS rRONICS RONICS rnONICS rRONICS rRONICS rRONICS i~g~:g~ rRONICS fRONICS rRONICS ELECTRONICS JAYCAR ELECTRONICS ELEC1RONICS JAYCAR ELECTRONICS ELECTRONICS JAYCAR ELECTRONICS ELECTRONICS JAYCAR ELECTRONIC~ ELECTRONICS JAYCAR ELECTRONICS ELECTRONICS JAYCAR ELECTRONICS ELECTRONICS JAYCAR EL~CTBQNICS BOOKSHELF Radio theory handbook for amateurs Radio Theory Handbook for Amateur Operators, by Fred Swainston. 2nd Edition published 1991 by Prentice-Hall of Australia. Soft covers, 211 x 277mm, 359 pages. ISBN · 07248 1043 9. When this book arrived in the SILICHIP offices, I thought, "Good, they are sure to have fixed the problems we found with the first edition and now we'll be able to recommend a good text for readers wanting to get their amateur ticket". I hoped this might be the case because, to be frank, we severely panned the first edition because of its poor or wrong circuit descriptions and many errors in the circuit diagrams. In fact , some amateur radio enthusiasts were so taken aback with the severity of the review that they asked me to list all the errors in the text so that they might be sent to the author, for correction in a later edition. This I declined to do. I thought it was up to the author and publisher to sort out the errors, not the reviewer. But now that I have read the second edition, perhaps I should have. Well, the bad news is that they haven't fixed any of the errors that were listed in our October 1989 review of the first edition. It is still a crook book. Are we being too critical? We'll list some examples of circuit errors and you can judge for yourself. This is just those we noted, not the total. On page 187, the power supply for the SSB receiver shows the output of the rectifier diodes being shorted to earth via a diode. On the same circuit, there is no blocking capacitor between the volume wiper and the following amplifier and so the volume control would be very noisy. Also the 9V regulator is shown as an ordinary diode rather than as a zener type. On page 210, a regulator circuit is shown with a LED connected across the 240VAC mains in series with a CON resistor. Was it supposed to be a neon indicator? On page 214 is an overcurrent protection circuit employing a transistor with three diodes connected to its base. This circuit cannot possibly work since a resistor is missing from its emitter. The voltage drop across the emitter resistor will cause the diodes to conduct when the current rises above a certain value. And yet the author has attempted to explain the circuit operation without mentioning the necessary voltage across the (missing) sensing resistor. The only conclusion which can be drawn from this is that he doesn't know how a current limiting (or constant current) circuit works. On page 212 is a battery charger which is supposedly variable in charge rate via a tapped voltage divider across its output. The circuit can only regulate its voltage output, not its current output. On page 218 is a mains filter (corrected from the first edition) which still has the errors we listed in our first review; namely, that the .047µF 500V suppression capacitors should be no larger than .0lµF and should be rated at 250VAC. This, of all the circuit errors, should have been corrected. The circuit descriptions are also very poor or incorrect. As an example, consider the following quote from a description of a choke input power supply filter (following a bridge rectifier): "To overcome the problem of inrush (current), a choke input filter can be used. The resistance of the choke is sufficient to limit the current to reduce the possibility of excessively high turn-on current. The cost of the chokes in these filters is high due to the relatively large amount of inductance required and the relatively low resistance. In some places, a low value of wirewound resistor is used in place of the choke". Now the foregoing is wrong on several counts. First, it is not the resistance of a choke filter which limits the in-rush current - it is the inductance of the choke which provides the limiting effect. Second, chokes have the effect of greatly increasing the conduction period of the diodes so that the ripple voltage is almost a pure lO0Hz sinewave rather than a sawtooth. One doesn't have to look far for other descriptions which are similarly wrong, vague or confused. Added to that, the author describes current flow in terms of electron current flow rather than conventional current flow, which makes the current flow around his rectifier circuits on page 204 look completely opposite to normal. And even so, if the voltage diagram for the bridge rectifier is correct, the voltage diagram for the fullwave rectifier is wrong. As we noted in our review of the first -edition, this text will probably fulfil its purpose of providing enough information to cover the Department of Communications syllabus for the Novice and Amateur Operator Certificate of Proficiency (AOCP). But is it too much to ask that all the circuits presented be correct and that the accompanying circuit descriptions be right? (L.D.S.) SC OCT0BER1991 53 Build a talking voltmeter for your PC Fancy a talking voltmeter with an on-screen display? This simple project mates with the PC Voice Recorder featured in the August 1991 issue & plugs directly into the printer port of your PC. venient to have to take your eyes off the circuitry to look at the voltmeter and it's all too easy for the probes to slip (and possibly cause damage) while doing so. Unlike the fancy handheld versions, the SILICON CHIP PC Talking Voltmeter plugs into a computer. This gives it the ability to store and later retrieve By DARREN YATES voltage readings over a given period of time. And by adding the PC Voice Talking voltmeters aren't new and However, they are often much more Recorder board, you can use speech there are now several handheld mod- convenient to use than conventional to relay the information to you. els on the market that can tell you the (mute) multimeters. This particularly What's more, we have replaced the current reading. These all use the lat- applies if you want to take a number American accent of the handheld est in artificial speech technology but, of readings in quick succession or if • models with a good ol ' fashioned unfortunately, this technology is still you have to concentrate on probe "Orstralian" one. You can even use new enough for them to be quite placement (eg, when measuring your own accent if you wish! pricey. voltages on IC pins). Often, it's inconOne very useful feature of the PC 54 SILICON CHIP Talking Voltmeter is that it can be used to monitor a voltage over time; eg, the voltage on an SLA battery under charge. In this mode, it can be set to give an audible alarm if the battery voltage rises above or falls below a preset limit. If you have a graphics card in your computer, you can also print out voltage vs. time graphs. This makes the unit ideal for checking battery performance under load, or for checking the stability of audio amplifiers, to give just two examples. The accompanying panel shows all the relevant specifications of the PC Talking Voltmeter. It has 8-bit accurac;y, better than 0.5% linearity and an input irnpedan.ce of lMQ. It plugs directly into the.parallel printer port of your computer and will measure DC voltages ranging between ±128V over three ranges, with an accuracy of about 2%. If you want the optional speech facility as well, you simply run an extra 2-wire connection to the PC Voice Recorder. Alternatively, you can delete the speech facility and simply operate the unit as a voltmeter with an on-screen digital display. Block diagram Take a look now at the block diagram of Fig.1. A part from the corn puter, the circuit uses a range switching stage, an input buffer stage, a comparator and an 8-bit digital-to-analog converter (DAC). Let's see how this all works. The input voltage is fed through the high impedance (lMQ) range selector and thence to the protected buffer (IC2a). The output of this buffer is then fed to the inverting input of the comparator (IC2b), while the noninverting input is fed from the output of the 8-bit DAC (ICl). This DAC converts the output of the computer which in turn responds to the output of the comparator. In operation, the input voltage from the buffer is compared with a voltage set up by the computer. At the same time, the computer also monitors the output of the comparator. If the comparator output switches from low to high, then the computer-controlled DAC output is too high. The computer then systematically searches for a lower value that is closer to the mark. Even though there· are 256 possible combinations, the car- Fig.1: block diagram of the PC Voltmeter. The input voltage is applied via a voltage divider & buffer stage IC2a to the inverting input ofIC2b where it is compared with the output from an 8-bit DAC (ICl). The DAC converts the output from the computer which in turn responds to the output of the comparator. VOLTAGE RANGE VOLTAGE INPUT □ rect 8-bit value that matches the input voltage can be found in just eight steps. What we really have is an 8-bit successive approximation analog-todigital converter (ADC). It converts our input voltage into an 8-bit code that the computer can recognise. Successive approximation Table 1 shows how successive approximation works. What we've done here is to show you how the successive approximation technique works on a step-by-step basis. Say for example that our input voltage is 1.83V. Our DAC has a conversion rate such that each of the 256 steps is worth 0.01 V. OK, let's start with row 1. Our input voltage is set to 1.83V, as we have said. We now set the most significant bit (MSB) of the DAC high, which represents half scale. This sets our DAC to 1.28V. We now check to see if the input voltage is in the upper or lower region of the DAC scale. Because the DAC output is lower than the input voltage (1.83V), the output of the comparator is low. This tells the computer that the input voltage is higher than 1.28V and so we leave the MSB high. We now go to row 2. We know that our voltage is in the upper half of the scale but is it towards the middle or the top end? We now set the next bit high as well, which produces an output voltage from the DAC of 1. 92V (ie, halfway between 1.28V and 2.56V). Since this is higher than our input voltage, the comparator output goes high, telling the computer that this bit must be set low. You can follow the rest of the rows yourself to verify that it works. The method is to start with the MSB and work down, checking at each step to see whether the result is higher or lower than the current input. It may take you quite a bit oftirne to work the Specifications Voltage range ................... ..... Resolution ............................. Input impedance .................... Accuracy ............................... ND converter ........................ Measurement rate ................. ±128V in three decade ranges 0.01 V, 0.1 V & 1V 1Mn approx. 2% 8-bit successive approximation type approx. 10 per second for 10MHz AT (depends on CPU clock speed) Computer requirements • XT/AT/386/486 IBM PC or compatible • CGNEGNVGA video card (for display of logged data only) • 360Kb.floppy disc drive • 256Kb bf memory (minimum) • MS-DOS 3.0 or later with GWBASIC • 1 parallel printer port OCT0BER1991 55 ,~.,~ I Digital/analog scale: LSB Current Bit Set = .01 V; Full scale ~ = 2.56V; Input voltage Comparator Output D/A Output Step 1 MSB 1.28V Step 2 MSB -1 1.28 + 0.64 Step 3 MSB-2 1.28 + 0.32 Step 4 MSB-3 1.28 + 0.32 + 0.16 Step 5 MSB-4 1.28 + 0.32 +0.16 + .08 Step 6 MSB-5 1.28 + 0.32 + 0.16 + .04 Step 7 MSB-6 1.28 + 0.32 + 0.16 + .04 + .02 Step 8 LSB 1.28 + 0.32 + 0.16 + .04 + .02 + .01 = 1.92V High MSB - 1 = 0 = 1.60V Low MSB - 2 =1 Low MSB - 3 =1 = 1.84V High MSB - 4 =0 = 1.8V Low MSB - 5 =1 Low MSB - 6 =1 = 1.76V = 1.82V = 1.83V High/Low LSB = 0/1 = 10110111 = 1.83V comparator to give us a result, this becomes our error. Even so, one step in 256 gives us an accuracy of about 0.4 % but there are other factors which have greater influence on the accuracy, as we shall see shortly. 0. The complete circuit diagram of the PC Voltmeter is shown in Fig.2. It uses just three !Cs, a couple ofregulators and a handful of other components. Circuit diagram The PC Voltmeter is housed in a low-cost plastic utility case & plugs into the parallel printer port of the computer. By connecting it to the PC Voice Recorder, you get a voltmeter that talks. SILICON CHIP =1 MSB result out by hand but the computer can do it much faster! If you look down the decision column in Table 1, you can write out the 8-bit code by starting with the MSB on the left and work across. In our example the 8-bit DAC code is 10110111, with the last bit either 1 or 56 Decision Low Digital word from DAC The last bit to be checked is the least significant bit (LSB). Because the two voltages applied to the comparator have to be different for the = 1.83V The heart of the circuit is !Cl, a DAC0800LCN 8-bit D/ A converter. Its 8-bit digital input comes from the parallel port of your PC (designated port A). By connecting pin 1 of !Cl to ground, we can feed the TTL outputs from the computer directly into !Cl and be assured of logic compatibility. Our reference voltage is set by two signal diodes, Dl and D2. This will give us a voltage which is close to about 1.3V. By now, some of you may be cringing about the accuracy of this reference but, before you give the idea away, we should point out that any error that occurs due to this source is corrected by the software. We built the prototype using components that came straight from the shelf and our PC voltmeter compared favourably with our Fluke multimeter. Obviously, it doesn't have the same resolution but the difference between the readings was only about 50mV on the 12.8V range! That said, this project is not designed to replace the multimeter - far from it! In fact, a digital multimeter will be very useful for checking out the final accuracy. !Cl is powered by ±5V supply rails, which we'll talk more about later. Its output takes the form of a differential current flow from pins 2 and 4. These outputs are fed to op amp IC2c, which is connected as a current to voltage converter as well as a subtracter. The resulting output from pin 7 of IC2c is a voltage which can take any ,_._ _ _ _ _ _ _ _ _ _ _....__ _ _ _ _ _ _ _ _....__ _ +5V VOLTMETER INPUT 680k 1% -_g. 4.7k 220k 1% 100k !.12.BV S1 180k 1% 1128V -5V .,. 02 IN914 +5V 01 1N914 PARALLEL PRINTER PORT 0825 CONNECTOR (2) 00 (3) 01 (4) 02 4.7k 4.7k 14 .,. .~ 13 12 4 11 I 10 GNO 2 IC1 OACOBOOLCN (5) 03 4.7k (6) 04 GNO I (19) GNO~ 0.1+ 15 4.7k .,. PCVOICE T O.,. ~ -5V .,. ~f 3 A VIEWED FROM BELOW OUT t=-"-'--1--- ♦SV + 100 25VWI (9) 07 (10) ACK ELJc ~K OUT REG1 IN 16 (8) 06 B IN 03 1N4004 ,.. .,. (7) 05 .. ffi 5 8 D5 .,. 1N4004 IC3 555 12VDC PLUG-PACK -i .,. 0.1 . 01I .,. PC TALKING VOLTMETER Fig.2: all the elements depicted in the block diagram can be directly related to the main circuit shown here. ICl, an 8-bit DIA converter, is the heart of the circuit. It accepts an 8-bit digital input from the computer & generates a differential output which is fed to IC2c, IC2c in turn drives the non-inverting input of comparator IC2b. value (in 10mV steps) between plus and minus the reference voltage; ie, between ±1.3V. This voltage is fed into the non-inverting input (pin 10) of IC2b, which acts as our decision comparator. The inverting input is derived from the input isolating buffer (IC2a), which is another TL074 op amp. Input divider The input voltage is fed into the buffer via a voltage divider with three positions: divide-by-100, divide-by10 and divide-by-1. To make sure that the input voltage range of the buffer is not grossly exceeded, a lO0kQ resistor is connected in series with the input. In addition, diodes D7 and DB ensure that the input voltage to IC2a can not rise more than 0.6V above the supply rails. IC2a is wired as a buffer stage and provides an extremely high input impedance (>10 12 ohms). This means that the input impedance is determined· by the voltage divider resistance (ie, lMQ). The output from IC2a appears at pin 1 and is fed directly into the inverting input (pin 9) of decision comparator IC2b. The decision comparator works like this. When the voltage applied to its non-inverting input from the DAC (and thus from the computer) is greater than the voltage on its inverting input, the output at pin 8 goes high. This lights LED 1 and turns on transistor Ql which then pulls the -ACK line of the printer port to ground. This -ACK line is checked by the computer during each cycle of the conversion process. It tells the computer whether the curreni. digital count is higher or lower than the input volt· age, as described previously. Power for the circuit is derived from a 12VDC plugpack supply, the same as for the PC Voice Recorder. This drives a 7805 3-terminal regulator via polarity protection diode D3 to derive a +5V supply rail. In addition, a -5V rail is derived using IC3 and a -5V regulator. IC3 is a 555 timer which is connected for astable operation. It produces a 750Hz squarewave at its pin 3 output and this drives a diode pump (D4 & D5) which is wired to produce a negative voltage (-9V approx.) at the anode of D5. This voltage is then fed to a 7905 regulator to derive the -5V supply rail. That's all we have space for this month. Next month, we will conclude with the constructional details. SC OCTOBER 1991 57 RITRON QUALITY OPTIONAL EXTRAS RITRON RITRON ADD PRICE TO BASE SYSTEM COST. c. •.•g.~. §,•~•80286-12 •s • • • • • • • w CPU 1 MEG RAM EXPANDABLE TO 4 MEG 16\Wlz LANDMARK SPEED TEST 1.2M JAPANESE BRAND F.D.D 42M HARD DISK DRIVE 28ms ACCESS 101 EXTENDED "CLICK" KEYBOARD JAPANESE KEYBOARD SWITCHES t/lNI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 ree) SERIAL, PARALLEL, GAME PORT 3 YEAR" AUSTRALIAN" PARTS & LABOUR WARRANTY 256K VGA CARD. DOS 5.00 IBM• COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE SOFTWARE INCLUDED. $ ASSEMBLED& TAXINC. TESTED IN AUSTRALIA RITRON POWER 1,489 $1,350 TAX EX 512K VGA CARD ....... $75 lM VGA CARD ....••••••• $150 80286-16 CPU 1 MEG RAM EXPANDABLE TO 4 MEG 21Mhz LANDMARK SPEED TEST 1.2M JAPANESE BRAND F.D.D 42M HARD DISK DRIVE 28ma ACCESS 101 EXTENDED "CLICK" KEYBOARD JAPANESE KEYBOARD SWITCHES MINI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 Re■) 2 SERIAL, PARALLEL, GAME PORTS 3 YEAR "AUSTRALIAN" PARTS & LABOUR WARRANTY 256K VGA CARD. DOS 5.00 IBM' COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE SOFTWAREINCLUDED. ASSEMBLED & TESTED INAUSTRAUA $1 ' 499 TO CHANGE A 40M HARD DRIVE TO A 85M HD add ........• $190 126M HD add ...•.•.... $450 200m HD add .......... $700 EXTRA RAM lMEG add ............ $100 2MEG add ............ $200 TAX INC. RITRON EXECUTIVE RITRON C•• • ·s .§§.;.§.1 • • • • • v (3869~~~~, 80386SX-20 CPU 1 MEG RAM EXP TO 4 MEG 27Mhz LANDMARK SPEED TEST 1.2M JAPANESE F.F.D. 512K VGA CARD BSM HARD DISK DRIVE, 18ma ACCESS 101 EXTENDED "CLICK" KEYBOARD MINI CASE & 200W POWER SUPPLY SUPA VGA COLOUR MONITOR (1024 x 768 Reaolution) SERIAL PARALLEL GAMES PORTS 3 YEAR "AUSTRALIAN" PARTS & LABOUR WARRANTY DOS 5.00 IBM• COMPATIBLE SPREADSHEET, WORDPROCESSOR & DATABASE SOFTWAREINCLUDED. • SHAREWARE SOFTWARE $1 899 ASSEMBLED & TESTED INAUSTRAUA. TAX INC. ' $1,710 TAXEX EXECUTIVE (4s§~Z§~ ASSEMBLED & TESTED IN AUSTRALIA. $2,795 ASSEMBLED & TESTED IN AUSTRALIA. $1,965 $2,395 ~:t TAX INC. $2,150 TAX EX INC. $3,895 TAX INC. $3,345 $3,695TAXEX. $2,995 TAXEX. ROD IRVING ELECTRONICS Est. 1977. MAIL ORDER HOTLINE: 008 33 57 57. (ORDERS ONLY) ENQUIRES: (03) 543 78n HEAD OFFICE: 56 RENVER RD, CLAYTON. PH: (03) 543 2166. FAX (03) 543 2648 CITY 48 A'BECKETT ST. MELBOURNE. PH. 663 6351 / 6391640. FAX: 639 1641. NORTHCOTE 425 HIGH ST. NORTHCOTE, PH. 489 8866. FAX: 489 8131. SYDNEY:74 PARRAMATTA RD, STANMORE. PH: (02) 519 3134. FAX: (02) 519 3868 ACN: 005 428 437 • . ;_ IEB.'. TAXEX. $2,785 TAX EX. ~i!~~t~i~il(<at> "J $ 4 395 $4,295 TAX INC $3,865 TAX EX Postage $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 J! ;i 80486-33 CPU ON BOARD CACHE. 4 MEG OF RAM 157Mhz LANDMARK SPEED TEST 200 MEG HARD DISK 12ms ACCESS TIME 1.2M JAPANESE BRAND F.D.D 3.5" 1.44M JAPANESE BRAND F.D.D 101 EXTENDED "CLICK" KEYBOARD SERIAL, PARALLEL., GAMES PORTS 1 MEG VGA CARD DOS 5.0 IBM' COMPATIBLE VGA COLOUR MONITOR (1024 x 768 Resolution) TOWER CASE & 220W POWER SUPPLY 3 YEAR "AUSTRALIAN'' PARTS & LABOUR WARRANTY SPEADSHEET, WORDPRCESSOR & DATABASE SOFTWARE. ASSEMBLED & TESTED INAUSTRAUA. IDEAL CAD MACHINE! ' TAX INC. WITH 200 MEG DRIVE TAXINC. $3,295 TAX INC. EXECUTIVE ·· ··- ir: 80486-25 CPU ON BOARD CACHE. 1 MEG OF RAM 115Mhz LANDMARK SPEED TEST 85 MEG HARD DISK 12ma ACCESS TIME 1.2M JAPANESE BRAND F.D.D 3.5" 1.44M JAPANESE BRAND F.D.D 101 EXTENDED "CLICK" KEYBOARD SERIAL, PARALLEL, GAMES PORTS 1 MEG VGA CARD DOS 5.0 IBM' COMPATIBLE VGA COLOUR MONITOR (1024 x 768 Resolution) MINI CASE & 200W POWER SUPPLY 3 YEAR "AUSTRALIAN" PARTS & LABOUR WARRANTY SPREADSHEET, WOROPROCESSOR & DATABASE SOFTWARE. WITH 200 MEG DR IVE WITH 200 MEG DRIVE RITRON ~•• • • •~•~•§z•~·•~·•·§ • • • •D TAX TAXEX. ' EXECUTIVE 80486SX-20 CPU 64K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 32 MEG 75"'1z LANDMARK SPEED TEST 85 MEG HARD DISK 18ms ACCESS TIME 1.2M JAPANESE BRAND F.D.D DOS 5.00 101 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 ' $2 195 ASSEMBLED & TESTED IN AUSTRALIA. RITRON RITRON $2 995 80386-33 CPU 128K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 16 MEG 57Mhz LANDMARK SPEED TEST 85 MEG HARD DISK 18ms ACCESS TIME 1.2M JAPANESE BRAND F.D.D 101 EXTENDED "CLICK" KEYBOARD SERIAL PARALLEL GAMES PORTS SUPA VGA COLOUR MONITOR (1024 x 768 Re■olution) MINI CASE & 200W POWER SUPPLY 512K VGA CARD (256 COLOURS) DOS 5.00 IBM' COMPATIBLE 3 YEAR "AUSTRALIAN'' PARTS & LABOUR WARRANTY SPEADSHEET, WORDPROCESSOR & DATABASE SOFTWAREINCLUDED. -SHAREWARE SOFTWARE iai~ :.':lUl 80386-10 CPU 128K CACHE ON BOARD MEMORY 1 MEG RAM EXP TO 16 MEG 57Mhz LANDMARK SPEED TEST 126 MEG HARD DISK 12m■ ACCESS TIME 1.2M JAPANESE BRAND F.D.D DOS 5.00 101 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 SORWARE $3,955 TAX EX. All sale■ tu exempt orders to : RITRONICS WHOLESALE rates llle•po•tage r••• .,. ba ■c po,1191 onlr up lo 5Kg. Rood high~ bulkr I frlglle ltonw wlll bi chorged II df,..,.,,t , .... 18 Renv■r Rd, Clayton, Victoria . Ph: (03) 1143 2168 Fax: (03) 543 2648 NAIL ORDER & CQRRESPQNDENCE P.O BOX 620, CLAYTON, VICTORIA. 3168. Error ■ 6 ommiMon ■ exceplad. Pttcae & 1pecllc1Uon1 _,bfeel ID chanflJ, 1 IIM 1 PC, XT. AT,.,. rwgl■ tarN ol lnllnwl.O<III 1..t,.., Machi-. tro-• ***GREAT :MoN1roRMovER-ARM7r---~=::::::--, 1/((,;~' I 11 fo;~~~"""'l~ r : I I IBM •, XT", TYPE 84 KEY KEYBOARD X12020 ............. ... ........ .... $109 Position your monitor I exactty where you want • Maximise deak apace! • Solid steel atructure • Span 33cm • Tray 30cm (tilting +/- 15) I 1 : j • Maximum load SO kg Give your computer that profes.aionel 1 I • Desk clamp range 3cm •7.Scm I ________________ C21079 .•.••..••.•••.•••.••. $199J 1 CPF CONTINUOUS POWER FILTEA SPIKE ARRESTOR The Fortron CPF Filtered Electronic Spike Protector provides a protectNe electronic barrier for m1crocomputers printers . telephone systems and modems electronic typewrite rs. aud io and stereo systems and other sens1t1ve electronic equipment 1-9 $9.95 10+ ~20092 $9.50 Size: 210 ll 11.5 x 30m ,P20094 $9.95 $9.50 Size: 210 x 25.4 x 50m C20096 $19.95 $17.95 Size: 210 x 25.4 x 100m C20098 $9.95 $9.50 !ize: 216 x 25.4 x 30m c20100 $11 .95 s11.5o Size: 216 x 24.4 x50m The C PF provides protection from d angerous alectncat spikes that can cause anything from obvious damage fhke immediate equipment la1lure ) 10 less obvious harm that can drashcally shor1en a system ·s Ille CP F s supenor cIrcu1Iry design and semi conductor technology resi:x>nd s instant ly to any potentially damaging over-voltage . ensuring sale trouble free operation Add1t1onally . CPFs filtering capability helps eliminate troublesome and annoying interference . general ha sh cre_ated by small motors . lluorescent lamps. and the like that threaten th e pertormance and shorten equipment hie of unprotected electronic components SPECIFICATIONS , Electrical rating : 220-260 volts (AC) 50Hz 10Amp Spike/RF! Protection : 4.500 amps for 20ml second pulses Maximum clamping voltage : 275 V ditterenhat mode CatX10088 $69.95 PRINTER RIBBONS TO SUIT: cPeo, sx8o, DP80, ex, oo, BX100, MB100, ,.e 10+ C:22036 .........$19.95 $17.95 MX80,FX80, RXSO, FX800, MX70, MX80, L.X800. C:22031 ......... $16.95 $15.25 MX100, FX100, RX100, L01000 C:22002 .......... $19.95 $17.95 80 003 .. ........ $12.95 $11 .95 TOH 8510 • 1550 051.. ........ $13.95 $12.50 NATIONAL PANASONIC _; ~ ENCLOSED PRINTER STAND c,,ossa-··'"-" look. X11105 ........ .... . Power supply I W) x11102 ..................... ....... s199 i TOP OF THE RANGE MINI TOWER CASE 200 X 415 x 330mm with 200w power supply x11100 ......................... S325 IBM COMPATIBLE EXTENDED KEYBOARD (101 KEYS) x12022 ........................... $ _/iirifl; 99 The top of the range! KEYBOARD STORAGE DRAWER NEW STYLE MINI TOWER CASE WITH POWER SUPPLY ::_:.$ 84.95 II~ MINI VACUUM CLEANER C21087.. ~ ... $14 .95 KEYBOARD COVERS C21089 84 KEY...... ... ... $4.50 C21088 101 KEY......... $5.95 RS232 BREAK OUT BOX A simple way ol monitoring RS232 anlertace lead activity. lnterfac:e powered. pocket size lor circuit testing. monitoring and patching 10 signal powered LED's and 2 spares 24 switches enables you to break out crrcuits or reconfigu re and patch any or al1 the 24 active positions Connectors: D825 plug on 80mm ribbon cable and D825 socket Indicators: Tricolour LED "s for TD . RD. RTS . CTS. DSR. CD . TC . RC . DTR. (E)1C Jumper Wires: 2011nned end pieces Power: lnlerface power Enclosure: Black . high impact plastic Dimensions: 85 x 95 x 30mm X15700 . $99.95 DISK NOTC HER ( onn·rh .'i 1/ 4" \inglt' \idt·d POWER SUPPLY FOR IBM•, PC/ XT", & COMPATIBLES DC OUTPUT: +5/13A .5 O.SA +12V /4.5 ·12 VO.SA X11096 ..... ...................... $139 200W SWITCH MODE POWER SUPPLY FOR IBM•, AT" & COMPATIBLES DC OUTPUT : +5/16A ·S/0.SA +12V/4.S ·12V / SA ·12/0.SA X11097 .......................... .. $149 UV EPROM ERASER It will erase up to 9 x 24 pin devices in comp1ete safety, in about 40 mi~utes (less time for less chips) • Chip drawer has conductive foam pad • Mains powered • High UV intensity at chip surface ensures EPROMs are thoroughly erased Ooppy disks to douhlt' \ idt.•d , h~· pladng an appropriatt' not«:h $169 ~m: applIcatIons -ff:) FREE , MICROSOFT . PAINTBRUSH SOFlWARE BRINGS YOUR COMPUTER TO LIFE. X19958 ........ IBM*CARDS DISK BOXES 100 x 5 1/4" ECLIPSE C16042 ................. .. ..... $11 .95 40 x 3 1/2" ECLIPSE C16040 .................... .... $8.99 120 x 3 1/2" LOCKABLE C16039 ........................ $21 .95 100 x 5 1/4" LOCKABLE C16020 ........... .............. $13.95 SO x 5 1/4" LOCKABLE C16025 ......................... $11.95 120 x 5 1/4" LOCKABLE C16028 ......................... $19.95 '*"r!'ll)i!-1 RS232-2 WAY .................... $39 RS232-4 WAY .. ................... $69 RS232·X OVER ... ................ $69 RS232·2 WAY AUT0 ............ $89 CENTRONICS 2 WAY ........... $49 CENTRONICS X OVER .. ...... $69 CENTRONICS 2way auto ..... $79 CENTRONICS 4 WAY............. $69 PC MONITOR EXTENTION CABLE 9 WIRE STRAIGHT THROUGH Without timer DB9 M/M 1.8 M. •••$14.95 X14950 .....................$99 WIRE PRINTER STAND in the flopp y di\k ja,:ket . DB9 M/M 3.0 IIL •••$19.95 C21054 ..ao column ....... $29.95 C:21070 .................. $7.95 With built-in timer DB9 M/M 5.0 IIL •••$29.95 DB9 M/F 1.8 M •••••$14.95 X14955 ................... C21056 •• 132 Column .... $34.95 D89 M/F 3.0 M •••••$19.95 ;J"H_I,~ MONTHS PRINTER SPECIAi!- 0KILASER 400 ONLY $1,399. ' D89 M/F 5.0 M .....$29.95 RS232 EXTENION CABLE 25 Head No.otcot Dr1ftSpeed NoJFont. Prtc• ~ ~ / ·; WIRE STRAIGHT THROUGH 0B25 M/M 1.8 M •••• $14.95 D825 M/M 3.0 M .... $19.95 L0-850 24 pin 80 264cps 3 $950 , _.,,,,..D825 M/M 5.0 'IJIJ. •••• $24.95 L0·1050 24 pin 80 264cps 6 $1050 D825 M/M 10 'IJIJ.. .... $39.95 LASER PRINTERS OL400 LASER PRINTER . L0•550 24 pin 80 1SOcps 3 $625 D825 M/F 1.8 'IJIJ.. .... $14.95 LQ.1010 24 pin 136 180cps 4 $795 4 PAGES/ MIN 25 FONTS ....... $1,399 D825 'IJIJ./F 3.0 'IJIJ.. .... $19.95 OL800 LASER PRINTER . OKI 172 9 pin 80 180cps 3 $275 D825 M/F 5.0 'IJIJ.. .... $24.95 OKI 380 24 pin 80 180cps 3 $650 8 PAGES/ MIN 36 FONTS .......... $1,995 D825 F/F 10 'IJIJ....... $39.95 200.Gx• 9 pin 80 213cps 5 colour $479 OL840 POSTCBIPJ LASER PRINTER D825 F/F 1.8 M ...... $14.95 GSX 140' 24 pin 80 192cps 6 colour $779 8 PAGES/ MIN 35 FONTS ..•.••••• $3,995 D825 F/F 3.0 M ...... $19.95 B25 F/F 5.0 M ...... $24.95 ~~~E ~❖~n :g Supports hunderds of POWER SUPPLIES : DELUX PRINTER STAND C21058 ........................$89.00 ~ o•·· SUPER BUS MOUSE 2 DESIGNED TO MICROSOFT MOUSE ~ RITRON EXECUTIIVE CASE X11089. Includes power aupply.....$195 ~ FREE mouse · house & mouse mat Plus FREE pop up menu software X19955 ...................... $69 .95 FIT THE PAlM OF YOUR HAND.I GREAT FOR SAVING A SERIAL PORTI 2 FREE TELEPAINT DISKS I X19951...... . .. $119 101 KEY TRACKBALL KEYBOARD Keyboard & mouse in one X12030.'--f .. $199.95 C21083 .. ~ Microsoft Compatible X11103 ......................$195 SPECIFICATIONS: ~ ~ o· QUICK MOUSE I ~ E:: ~~ ~«f!Jv:~~ XT HD CONTROLLER....•.. $129 AT HD CONTROLLER ....... $149 - . . - - - , RS232/SERIAL CLOCK. .... $49 MONO COLOUR CARD ...... $76 MULTI 1/0 CARD................. $99 PRINTER CARD.................. $29 EGA CARD.......................... $179 DIAGNOSTIC CARD........... $795 TTL PRINTER......................$89 6M AT EX/EXP..................... $325 FAX CARD........................... $595 4 PORT SERIAL CARO ...... $199 2 WAY FOO CONT (360) ..... $3g RS/232 SERIAL CAR0 ........ $39 GAMES CAR0 ..................... $29 AT S/P/G 2 S/P/G ................ $49 4 WAY FOO CONTROLLER (360·1.44M) ......................... $129 2 WAY FOO CONTROLLER (360·1 .44M) ......................... $89 CLOCK CARO .................... $39 SMART DRIVE ADAPTOR IDE/FDC............................... $49 SMART DRIVE ADAPTOR IDE 1/0 FDC ......................... $89 512K/576K RAM CARD .......$9g VGA CARD 16 BIT 2501<. ... $129 VGA CARD 16 BIT 512K.... $1 79 VGA CARD 16 BIT (1 MEG). $239 IBM PRINTER CABLE, 25 WIRE STRAIGHT DB25/CN36 M/M 1.8 IIL ••$14.95 DB25/CN38 M/M 3.0 IIL .. $19.95 DB25/CN36 M/M 5.0 IIL •• $24.95 DB25/CN36 M/M 10 M .... $39.95 IBM PRINTER CABLE, 25 WIRE RIIGHT ANGLE DB25/CN36 M/M 1.8 !IL •• $19.95 DB25/CN36 M/M 3.0 IIL •• $24.95 DB25/CN36 M/M 5.0 IIL •• $29.95 DB25/CN36 M/M 10 M. •• $44.95 RS232 EXTENION CABLE 25 WIRE STRAIGHT THROUGH D825 M/M 1.8 IIL •••$14.95 0B25 M/M 3.0 IIL •••$19.95 D825 M/M 5.0 IIL ... $24.95 0B25 M/M 10 M •••••$39.95 D825 M/F 1.8 M ••••• $14.95 D825 M/F 3.0 M ..... $19.95 D825 M/F 5.0 M ..... $24.95 D825 F/F 10 M. •• •••$39.95 Digital altimeter for gliders & ultralights, Pt.2 Although it uses a fair amount of circuitry, the Digital Altimeter works in a fairly straightforward manner. This month, we look at the circuit details. ig.3 shows the full circuit diagram for the Digital Altimeter. It might look complicated at first glance but, in practice, can be easily split into sections and related back to the block diagram (Fig.2) to get a clearer picture. All the elements depicted in the block diagram last month are there. ICla provides the reference voltage; IC3 , IC4 & IC5 are the amplifier stage; IC7, IC9 & IClO form the curve shaper; F LARKE 60 SILICON CHIP ICl 1 & IC12 provide barometer/altimeter select; and IC13 is the 3½-digit display driver. Let's take a closer look at each section in turn, beginning with the voltage reference. Voltage reference This part of the circuitis based on ICl (LMlOCN) which is a combined voltage reference/buffer and op amp. ICla buffers an internal 200mV reference on its non-inverting input and is set for a nominal gain of 30 by means of VRl which is in the feedback loop. This allows the reference voltage output on pin 1 to be set to +6V exactly. The lOµF capacitor across the feedback resistance is there to reduce noise. It must be a tantalum type as specified, to ensure low leakage. The +6V reference voltage from ICla is now fed to various parts of the circuit, either directly or via buffer/ divider stages. First, it provides a direct +6V supply for the SCX15ANC pressure sensor. Second, it is divided down using two separate dividers and fed via buffer stages IClb and IC6 to provide the +l.25V and +ZV references for the curve shaping circuitry. Third, it is fed via VRZ and buffer stage ICZ to derive an offset bias for IC3 & IC4. And fourth, it is divided down to provide a +3V reference for the REFHI input of IC13. The SenSym SCX15ANC pressure sensor is a temperature compensated device with a differential output at pins 3 & 5. This differential output is a nominal 45mV (±2.5mV) at 1034hPa air pressure and 0V (±lmV) at vacuum. In this circuit, however, the sensor has to cover the range from 1034hPa to 466hPa (about 20,000ft) and thus its output only varies by a nominal 24.72mV (ie, from 45mVto 20.28mV). Amplifier Op amps IC3, IC4 & IC5 are used to boost the small differential output voltage from the pressure sensor to a usable level, before it is fed to the curve shaper. These op amps and IC2 are all OP-77 types from Precision Monolithics Inc (USA) and have been chosen for their low input current requirement, low offset voltage and excellent temperature stability. IC3 & IC4 are connected as a differential amplifier with their non-inverting inputs (pin 3) connected across the pressure sensor. Because these non-inverting inputs have a very high input impedance, the loading on the pressure sensor in negligible. Taken together, IC3 & IC4 provide a total gain of 38.67 which is fixed by the 22kQ feedback resistors and the 1.2kQ resistor between the two inverting inputs. As previously mentioned, IC2 buffers an offset voltage which is derived from ICla via trimpot VR2 . This_allows pin 6 of IC4 to be set to 2.00V at 1013hPa air pressure. Note that the four 22kQ resistors used for Rl are all in a thick-film single in-line package. This ensures good temperature tracking of the resistance values so that the amplifier parameters do not vary with changes in temperature. Similarly, the R2 & R5 voltage divider resistors are also in a single inline resistor packages to ensure good temperature tracking. Following IC4, the amplified sensor output signal is fed to op amp stage IC5 . This stage operates with a nominal gain of 2.73 but in practice can be adjusted from 2.38 to 3.00 using VR3 to compensate for tolerances in the pressure sensor. The inverting input (pin 2) of IC5 is referenced to +2V and so its output swings between +2V and +4.5V for air pressures from 1013hPa to 463hPa. For air pressures greater than 1013hPa (which is nominally below sea level in a standard atmosphere), the output of IC5 can swing below +2V to give a negative reading on the display. IC5 is necessary for two reasons. First, we can't increase the gain ofIC3 Power for the Digital Altimeter is derived from an internal 9V battery which has an operational life of about 50 hours. Alternatively, you can remove the battery & substitute a 9V regulator circuit (to be described next month) so that the unit can be run from an external 12V DC supply. & IC4, since this would upset the offset adjustment circuit (IC2). Second, the addition ofIC5 allows us to adjust the gain of the amplifier circuit during calibration without upsetting the offset adjustment. The lO0Q resistor at the output of IC6 isolates the op amp from small capacitive loads to prevent instability. As a further precaution against instability, this resistor feeds a 4. 7µF capacitor which swamps the effect of any small capacitive loads on the output. The resulting +2V supply from IC6 is applied to Vrw of the following analog to digital (AID) converter (IC7), and is used as a reference for the 32step curve shaper and the ICL7106 display driver. Curve shaper IC7 is an 8-bit A-D converter which converts the 2-4.5V analog output of IC5 into a digital value at its Data outputs (D0-D7). In this case, we have used only five of the eight outputs; ie, from D7 to D3. As we've just seen, the Vrw input of IC7 is set to +2V by the output of IC6. IClb applies a 1.25V reference to VREFl2 and this sets the range of the AID converter to 2.5V (ie, from 2V to 4.5V). Note that IClb simply buffers the 1.25V output produced by a voltage divider on the output of ICla. The 75kQ resistor between pins 6 & 2 of ICl b is there to equalise the input bias currents into its two inputs. In operation, the AID converter (IC7) produces an 8-bit binary output signal ranging from 00000000 for a 2V input to 11111111 for a 4.5V input. These outputs are updated every lO0µs , as set by the external clock components on pins 4 & 19 (lookn & 220pF). To ensure that the AID converter starts reliably, NAND Schmitt triggers IC8b and IC8c briefly ground the WRbar input (pin 3) at power on. This works as follows . At switch on, the lµF capacitor on pin 9 of IC8b is initially discharged and so pin 10 of IC8b is high. This high is then inOCT0BER 1991 61 --------------•5v· REFERENCE 100k +9V _ _ _ _.,.9VREF/2 19 CK 100 +9V 4 OFFSET ADJUST VR2 <J------,---"4 100k 1k .,. 04 14 05 13 2 IC7 061'-=---- -- - - -- -- -- - - - - - , ADC0804LCN ..,1.,___ _ _ _ _ _ _ _ _ _ _ _._._ __, 07 CS 1 CK D 0 TP1 +6V +5V GNDA 8 +6V .,. R2 100k 6 7 03 15, A•D CONVERTER .,. . GND_f 220n R1 22k 0.1 1.2k R1 22k TP4 3,3k 6 +9V DIFFERENTIAL AMPLIFIER· 138.67! R5 22k R5 22k 0.1 R5 22k GAIN x2.38·3.00 t SPAN 2·4.5V i R4 100k 0.1! .~. B rLJc VIEWED FROM BELOW ~ verted by IC8c to produce a low on pin 3 of IC7. When the 1µF capacitor subsequently charges via the 100kQ resistor to the 5V rail, pin 8 of IC8b goes high and enables the gate. IC8b & IC8c now gate through the INTR-bar output of IC7 to the WR-bar input at pin 3. The five AID outputs from IC7 are used to switch in various sections of a SILICON CHIP +5V 32 STEP DIVIDER 2·4V OUTPUT +5V· +9V GIIIIS 62 16 + 4.7 16VWJ_ -:- OUTOIN GND TP3 +2V + *0.1 *710.1 " *MONOLITHIC resistive voltage divider string, the values of which have been selected to give an output that closely tracks the required pressure vs altitude curve (see Fig.1). The five output lines from IC7 give us 32 possible values, which is perfectly adequate to cover altitudes up to 20,000ft. Refer now to Fig.1 in last month's issue. The straight line on the graph shows tµe 2-4.5V output of the amplified pressure sensor voltage (normalised here as 0-2.5V). Fig.1 also shows how the AID converter changes its output code at every 78.125m V (2 .5VI 32) change in input voltage; ie, at each step in the staircase waveform. The staircase waveform is the amplified pressure sensor output after it has passed through the voltage di- ~-----------------------♦9V 0oN ~OFF T 9V l1 01r;~ 1N4148\,: -B~ATT~--• ~ f:/, tl_ I ZD1 ~A LED1€~ ;>.. :-1- 40~~"w C> S2 . _/- xv I- I BAROMETER.; INH REF., .01:= TOP7___,_ _ _ _ _ _3"'12 COM 1f- +9V +6V 2V tJ IC12c 3 - - LI§ REFLO .01:= >--m A3 23 100k 39 OSC2 511111 1051 TO 843hPa 47k 27 26 ~3 14 115 29 124 25 23 22 17 18 19 20 21 3-1/2 DIGIT LCD 11 10 .. 100pF 38 :: OSC3 160k 9 31 32 ~ ~~ 50-00-'--""-"W k .--41>-=t> L IC13 ICL7106CPL 5 ~-J BAROMETER G2 25 r - - - - '4"'IO OSC1 \- 9 ~ 20k . F213 L • 3 1sf . 14 . . - - - - - - - - - - - - - - - - - '"'IO IN,o 1 -,000':,. . . 36 6 61,-.7- - - - - - - - - - - - - - , A2 12 11 B2 C2 10 9 D2f-- - - - - - - - - - , E2 14 1 -..... 14 31 1NH1 --0-f-"-''--------+---+-'W MV.--....----"'1 .:;- -- F1 R3 22k ~ ~ \ ---E CREF - 47k 11 12 13 10Jm~g:T~ ~~~~ii 0.47: = y 5 B1 4 3 c1s::- - - - - - - - - - - - - - - - - - , 2 01s::- - - - - - - - - - - - - - - - E1,-.B_ _ _ _ _ _ _ _ _ _ _ _ _ _ __, TP6 IC12a 4053 j GAINSET VR5 5k R3 22k R3 22k +2V ~ CREF R3 22k_ -r.,__~8':il-+_3~30NQ~-+K_ _..::;AL=TY- + A1 +6V BAR O .0 47 glj AUTO ZERO •2 .ll BUFFER .lJ INT GAIN ·2.6 TO -3.1 IC12b 10 H BP ."?:,_>-t2'--_ _ _ _ _ __,120 121 ~6 Jlil-,o--""a=>-+'1_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __, R1 ,R3,R5 = 22k RESISTQRIARRAY R2,R4 = 100k RESISTOR ARRAY DIGITAL ALTIMETER vider string. As can be seen, it follows the altitude vs pressure curve to within 1.1%. Now go back to the main circuit diagram (Fig.3). IC9 and IClO are 8channel analog multiplexers with three binary control inputs. These control inputs are at A, B & C (pins 9, 10 & 11) and they control which of the eight inputs is switched through to the output at pin 3 (COM). The INH input at pin 6 disconnects the COM output from any of the inputs when taken high. In this circuit, outputs D4-D6 of the A/D converter (IC7) are fed to the control inputs of IC9 & IClO, while output D7 (the most significant digit) controls the INH inputs. In the case of IC9, however, D7 controls the INH in- Fig.3: the complete circuit diagram for the Digital Altimeter. ICta provides the reference voltage; IC3, IC4 & IC5 form the amplifier stage; IC7, IC9 & IC10 form the 32-step curve shaper; ICt 1 & IC12 provide the barometer/altimeter select function; and IC13 is a 3½-digit AID converter & display driver. OCT0BER1991 63 Despite the apparent circuit complexity, the Digital Altimeter is easy to build & adjust. Note the foam insulation underneath the two main boards. This serves to thermally insulate the unit & helps prevent drift due to temperature variations brought on by altitude or weather changes. put via inverter stage IC8a. Thus, when D7 is low, IC10 is selected and IC9 is disabled. Conversely, when D7 is high, IC9 is selected. By wiring the INH inputs in this manner and by connecting their COM outputs together, IC9 & IC10 are made to function as a 16-channel selector. In operation, it simply selects the.correct tapping on the voltage divider string attached to the inputs. The least significant bit that we have used from the AID converter (IC7) is D3 and this is used to control transistor Ql. When D3-is high, Ql is on and Q2 is off. In this situation, the resistive divider consists of the 3.3kQ resistor at the output of IC5 and all the resistors connected to the inputs of IC9 & IC10 (ie, there are 16 steps). Conversely, when D3 of IC7 is low, Ql is off and Q2 is on. This connects a 200kQ resistor across the resistor string at the bottom of the 3. 3kQ resistor. Thus, a lower divider ratio is selected compared to that selected when 64 SILICON CHIP the D3 output of IC7 is high and this provides another 16 steps to give the required total of 32 steps in all. Thus, the AID converter (IC7) and the two analog multiplexers (IC9 & IC10) are used to select one of 32 possible voltage divider values to attenuate the signal at the output ofIC5 . This attenuated voltage appears at the COM output of either IC9 or IC10 and is fed to IC12a. Altitude/barometer selection IC12a is one section of a 4053 CMOS analog switch. It passes signal from pin 12 to pin 14 when the control input (pin 11) is low, and from pin 13 to pin 14 when the control input is high. As shown, pin 11 is connected to the wiper of S2 and is switched either high or low to select the BAR and ALT modes respectively. Thus, when S2 is in the ALT position, pin 11 of IC12a is pulled low and the output from the curve shaper is fed through IC12a to the INHI input of IC13. IC13 in turn drives the 3½digit LCD which shows the altitude in feet. IC13 is an Intersil ICL7106CPL 3½digit AID converter and display driver. We briefly examined this device last month but let's quickly recap on how the REFHI, INHI, INLO and COM inputs work. The REFHI input is set to +3V (which sets the input voltage range), while the common-(COM) input is fixed at the +2V reference voltage. Any voltage applied to the INHI or INLO input is with respect to this common voltage. Thus, any voltage above +2V on the INHI input will give a positive reading, while any input voltage that's less than +2V will give a negative reading. For the INLO input, if the input voltage is e,bove +2V, it subtracts from the voltage on the INHI input. If the voltage is less than +2V, it adds to the voltage on the INHI input. If both the INHI and INLO inputs are at +2V, the display reads zero (ie, 000). OK, let's now go back to the ALT/ BAR select circuitry and see how tb.e barometric offset adjustment works. As explained in Pt.1 , this circuit is necessary so that the altimeter can be set to read zero feet on the ground, or so that it can be adjusted to read altitude above a set pressure level. As with IC12a, IC12b and IC12c both have their control inputs (pins 4 & 10) connected to the wiper of switch SZ. IC12b connects the minus output (pin 20) of IC13 to the LCD minus input (pin 2) in ALT mode and is used to switch off the minus sign when in BAR mode. More on this later. IC12c selects either the output of ICl 1 in the ALT mode or the wiper of VR6 (Barometer Adjust) in the BAR mode. The output app ears at pin 4 and is fed directly to the INLO input of IC13 where it subtracts from (or adds to) the voltage on the INHI input. A look at the pressure vs. altitude table published last month shows that for altitudes from 0- lO00ft, the height varies by about 27.7ft per hPa. However, at altitudes ranging from 40005000ft (the limit of the offset adjustm ent), the height varies by about 31.26ft per hPa. Compensating for this non-linearity, so that we get the correct reading, requires some tricky circuitry. At low altitudes, the display should change by 2 7. 7ft for each lhPa change in the offset adjustment, increasing to 31.26ft for each lhPa change at around 5000ft. As a further complication, the altitude reading must decrease as the barometric offset is wound down. This is the reverse of what normally happens when the unit is functioning as an altimeter. Despite these complications , the resulting circuitry is quite simple. For the BAR mode , we need the display to indicate 1013hPa when the INLO input is at +ZV since this is the reference air pressure. This is achieved by switching through a fixed voltage from VR4 via IC12a to the INHI input of IC13 (ie , trimpot VR4 is adjusted to give a reading of 1013 when INLO is at +ZV). Note that because VR4 is connected between ground and +ZV, the voltage on its wiper will be less than the +ZV reference and this would normally give a negative reading on the dis-· play. This problem is solved by switching off the minus sign using IC12b. It works like this: when BAR is selected, pin 10 of IC12b is high and so IC1 2b switches the backplane (BP) signal at pin 21 of IC13 through to the minus Fig.5: full-size artwork for the sensor & amplifier PC board. input (pin 2) of the LCD. Thus, the minus sign turns off. VR6 is used to provide the control voltage for the barometer offset adjustment. In the BAR mode , IC12c switches the wiper of VR6 directly to the INLO input. If the voltage on the w iper is less than +2V, the barometric reading redu ces. Conversely, if the voltage on the wiper is greater than +ZV, the barometric reading increases. Variable gain stage OK, so much for barometric offset adjustments in the BAR mode. In the A LT mode, as we've already explained, the display must change by 2 7. 7ft/ hPa at low altitudes and increase to 31.26ft/hPa at altitudes of about 5000ft. This is done, by multiplying the voltage at the wiper of VR6 using variable gain amplifier ICl 1. In greater detail, ICll is wired as an inverting amplifier with its noninverting input biased to +ZV via a 47kQ resistor. The gain of this stage depends on the setting of VR6 and thus on the barometric reading. It varies from 2.6 for barometric readings around 1051hPa up to 3.1 for barometric readings around 843hPa. To understand how the gain varies, assume first of all that the wiper of VR6 is at the lkQ resistor end of the pot. In this case, the gain of ICl 1 will be 160kQ/(51kQ + lkQ) = 3.1. Wh en the wiper is at the other end, the l0kQ potentiometer becomes a part of the input resistance and so the gain changes to 160kQ/(51kQ + lkQ + 10kQ) = 2.6. For intermediate settings of VR6, the gain varies accordingly. ALTIMETER ALT. Multiply alt. by 10 for height in feet + BAR. BAT. OFF ON I + ~ BAR ADJ . (hPa) Fig.6: this full-size artwork can be used as a drilling guide for the front panel. OCT0BER1991 65 d 0 ll°l --------~- N--- ill a--a 0 Fig.7: full-size artwork for the battery & display driver PC board. Fig.8: full-size artwork for the display PC board. Note that the gain is always 1/loth the altitude change per hPa. This is because the altitude is displayed in tens of feet rather than in feet. The output from ICl 1 appears at pin 6 and is switched through to the INLO input ofIC13 by IC12c (since pin 9 of IC12c is now low). Thus, by suitably adjusting VR6, the Digital Altimeter can be zeroed for any altitude between -lO00ft and +5000ft. This corresponds to a barometric offset adjustment range of 1051-843hPa. Trimpot VR5 allows the unit to be accurately calibrated to cover this offset adjustment range. 66 SILICON CHIP IC13 and its accompanying liquid crystal display basically functions as a 0-1. 999V millivoltmeter. Inside ICl 3 is a dual slope AID converter which operates from an on-board master clock oscillator. This clock operates at a frequency of 48kHz as set by the l00pF capacitor and l00kQ resistor on pins 38, 39 & 40. This results in a display update of three times per second. IC13 is calibrated by the +ZV reference voltage on its REFLO input and the +3V reference voltage on REFHI. This 1V difference results in a 0-ZV range on the display; ie, for a 1V input (with respect to COM), the display reads 1000 (10,000ft). The various segment driver outputs from IC13 are all connected directly to the LCD, the only exception being the minus sign output which we have covered previously. A segment is turned on by applying a signal to it which is identical to, but 180° out-ofphase, with the backplane signal on pin 1. Conversely, the segment is turned off if the signal applied to it is in-phase with the backplane signal. Note that the three decimal points (DPl, DPZ & DP3) and the L, Z & X segments are all permanently disabled by connecting them directly to the backplane pins (1 & 40) of the display. Power supply Power for the circuit is derived from a 9Vbattery via on/off switch Sl. This directly supplies most of the circuitry, including the A/D converter (IC13), the voltage reference and the op amps. It also drives an LP2950CZ-5 3-terminal regulator which provides a +5V rail to power IC7, ICB, IC9 & IClO. The lOµF capacitors at the input and output of the regulator are there to improve transient response and to ensure stability of the regulator output. In addition, a number of 0. lµF capacitors are connected across the supply rails at various points on the circuit to provide further supply decoupling. Sl also has a battery test (BATT) position. When this latter mode is selected, current flows through LED 1 via a series 4. 7V zener diode and 330Q resistor. Since the voltage across the LED must be about ZV for it to turn on, it will go out if the battery voltage drops below 4. 7 + 2 = 6. 7V. In practice, the LED will be only dimly lit at about 7.ZV, thus indicating that the battery should be replaced. Note that, in the battery test mode, power is supplied to the rest of the circuit via Dl. The cathode of LED 1 is connected to the ALT terminal of SZ and so this terminal is pulled high when Sl selects BATT. For this reason, the altimeter operates only in BAR mode when the battery test func tion is selected, regardless of the setting of SZ. That completes the circuit description. Next month, we'll resume with the full construction and calibration details. SC W(X)D FOR CHIPS... W(X)D FOR CHIPS... W(X)D FOR CHIPS... W(X)D FOR CHIPS... WOOD FOR CHIPS...WOOD FOR CHIPS... WOOD FOR CHIPS... WOOD ~ EPROM . ., ~ ~ U:.~ SPECIAL HUSKY EPLD/EPROM/ MICRO/GANG/SET Programmer SHOOTER Stand Alone EPROM/Micro Programmer 27C010-200 40pin Dual in Line • Direct drive from PC via 1MB EPROM1ust • Ideal for personal projects high speed parallel ~1 g 95 each and small industrial users Take a close look at APPA interface • • Works with any MS-DOS multimelers. Look familiar? That's because they're sold under different compatible PC or dumb • Four 32 pin ZIF sockets brand names. And that means you • terminal with serial port • Programs in SET or GANG could pay a lot more than you need mode for up to 4 single Copies and veriliet in standto. We've seen the top of the line model selling at around $150 more EPROMs or 4 CMOS 20/l4 alone mode than our price. So you're payi ng that Programs 2716-27512's pin EPI.Ds much extra Just for the brand label! • Completely software driven • 125x200mm slid-out tray including 'A' and CMOS • Optional adapters for single with anti-static pad • Programs 8751/87C51 chip Micros, CMOS 20/ • UV indicator Micros with adapter 24pin EPLDs and PLCC/PGA • 7700 hour /amp life • Built-in debug firmware packaged devices • 15,000microwatt/sq cm enables RAM editing and • Husky software is menu intensity display with terminal driven plus mouse or cursor • Safety interlock switch • Fast intelligent algorithms $133.80 ex tax • Built-in RS232 port at 110, • Supports devices up to 2MB 300, 1200, 2400baud • Sottware updates available $155 .211 inc tax • Uploads and downloads $776.25 ex tax Intel hex, Motorola hex, $906.00 inc tax ASCII hex or binary files Quv T8/N Industrial EPROM Eraser Why pay up to $150 for a label? • • $680.00 ex tax, $795.00 inc tax This is an MS-DOS software and cabling package which offers sophis1icated facilities at a fraction of the cost of dedicated hijrdware systems. SerialTest provides a window onto RS232 lines operating either passively or actively sending data or controf signals to simulate either at DTE or DCE device. Triggers can be defined based on error conditions or data to Initiate or terminate monitoring sequences. $425 ($395 ex tax) Send $10 for a demo disk, refundable on purchase. Kikusui 40MHz 2 Channel Scope • 5mV/div de to 40MHz • 2Dns/div to O.Ss/div Main • 0.2µs to 0.5ms/dlv Delayed • Includes x1/X10 probes • 2 year warranty C0S5041 $1372.50 ($1178.50extu) setting • Probs st11rag1 c11s built In tor easy two hanlkl 1111asu19msnts • T/16 116 is water 19s/stance tor industrial use • Shockproof tar a drop of 1.5ml • Built-in lilt stand : ';UL1244 ;:'/,'t',iZ'standards i4iWt,~-::~,torand safe apsralion Model 93 e 1999 count • Large 2Dmm high contrast LCD readout • 8 Functions - Vdc, vac, Ade, Aoc, Ohms, Diode, Frequency, Capacitance • 0.5% de accuracy $142.80 Rangss Vdc 200mV, 2V, 20V, 200V, 1ooov Vac 200mV, 2V, 20V, 200VAJ~OV Ade 200uA. 2mA. 20mA, 2wmA, 2A, 20A 2mA, 20mA, 200mA, Aa~l~· Don't forget we stock a full range of EPROMs and other microprocessor chips. See Review in E.A. May SerialTest serial data analysis on your PC Look at ths fsatU19S • Lary11 high contrast display • Thil 96 and 98 h;ws anali,g bar graphsl1Jo • Colour colkld Input 18rmlnals and function switch tor easy Just what the Serviceman needs! INFRA-RED ROLACASE KIT Portable Storage •BARRIER 15met19 range • 2 Outputs no/nc Systems • Fast 19sponst1 • • • • Ideal for vehicle storage Easily indexed Take with you to the job Static conductive to prevent damage to delicate components • Ideal for mining, gas etc industry where extra safety Is required • High impoct ABS • Infernal Dimensions 360x360x75mm • Choice of two types Blue, single compartment $57 .20 Orange, divided Into 20 compartments $64.95 • Storage rack holds 3 cases tor vehicle or bench $1 55.00 • Mounting casss included • Easy 111 align • Law pow,r drain - 12V/45mll • DBIBCIS ob/BCIS 10mm dia1111tsr The ATM20 uses high frequency coding to minimise interference from sunliiht etc. High ~ower ~~l~~J:c nology and ow noise Ideal for use in Speed detection systems up to 999.9kph! Security Camera trigger for wildlife photos Complete kit uses finest components, has comprehensive instructions and is complete down to terminal strips $58.20 We stock the full range of Pro fessional AT& M Kits Don't design y Jr own Send for our list and save a fortune ! Save Problems and Cost with MEMOREX Fluke 70 Series II Multimeters in stock GENUINE PREMIUM GRADE DISKS 51/4 2S/2D $16.95 per 10 Mode{ 70 True Fluke quality 5 1/4 2S/HD $24.95 per 10 1150inctax! foron/y 31/2 2S/2D $24 • 95 per 10 Model 751/ 0.4%, 10A range, TouchHold™ 81$312 inc tax _a_1_,_2_2_s_,_H_D___ $4_9_._9_5_p_e_r_1_0_... Geoff Wood Electronics Pty Ltd Ohms 200Q, 2kn. 20k0, 200kn, 2Mn, 20MO Frequency 2kHz 20kHz, 200kHz Capacitance 2nF, 20nF, 200nF, 2µf, 20µf Also available Mods/ 93T with transistor tester in place ol 2A range $142.80 Modef 96 • 31/2 digit plus 41 segment analog bar graph • Autoranging or manual selection • 6 functions - Vdc, Vac, Ade, Aac, Ohms.Diode • Water resistant • Data hold • Memory offset Rangss Vdc200mV, 2V, 20V, 200V, 1000V Vac 200mV, 2V, 20V, 200V,J~OV Ade 200uA, 2mA, 20mA, 2wmA, 2A, 20A · Aac 200uA, 2mA, 20mA, 200mA, 2A, 20A Ohms 20Dn, 2k0. 20kn. 200kn, 2Mn, 20Mn $166.80 Model ."iJ • 3 1/2 digit plus 41 segment_ analog bar graph • Autoranging or manual selection • 8 Functions - Vdc, Vac, Ade, Aoc, Ohms, Diede, Frequency, Capacitance • Data hold • Memory offset Rangss Vdc 200mV, 2V, 20V, 200V, 1000V Vac 200mV, 2V, 20V, 200VA 75/N Ade 200uA, 2mA, 20mA, 2uDmA, 2A, 20A Aa~l~· 2mA, 20m_A. 200mA, Ohms 20Dn, 2k0, 20kn, 200kn, 2Mn, 20Mn Frequency 2kHz 20kHz, 200kHz Ca~~tance 2nF, 20nF, 200nF, 2µf, $214.80 Model 76 Component Tester Does the things your multimeter doesn't! • Capacitance 200pF to 20uf • Resistance 2000 to 20Mn • Transistor hie and lceo • Diode displays VI at 1mA • LED disgla!i VI at 2Ma and 10mA : ~ie~as~~aifYefrd 1.5V cells $142.80 (i nc In N s W) 229 Burns Bay Road, {Corner Beatrice Street), Lane Cove West N S W Mail Orders to -'PO 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 acx::epted if the line value exceeds $10.00 BANKCARD, MASTERCARD, VISA, CHEQUES or CASH cheerfully accepted. AMATEUR RADIO BY GARRY CRATT, VK2YBX How to optimise an HF antenna for multihop operation HF transmissions can travel great distances by being bounced off the ionosphere but taking advantage of this fact is not easy. This article gives the background you need to set up and aim your antenna. Most HF communications use "sky wave" as the means of propagation. In this mode, the radio wave leaves the transmitting antenna and travels upwards to the ionosphere until it is reflected back to Earth. The ionosphere is located 100-400km above the Earth's surface and because it is made up of several layers (due to solar radiation), is an extremely dynamic and highly unpredictable medium. When the signal arrives back at the Earth's surface after reflection, it is again reflected skywards where the process may be repeated. During each TRANSMITTING ANTENNA D E F1 F2 reflection, part of the signal is absorbed and attenuated, and the amount of signal lost depends on the frequency, density of the atmosphere and the ground conditions; ie, whether land or sea. Fig.1 shows the principle of these "skip" transmissions. Ultimately, there is a limit to how often this process can be utilised. Multihop transmissions can occur over ranges up to 2400km. In order to obtain the maximum performance between two known points (ie, to minimise the free space attenuation between those two points), 70-90km 105-120km 145-190km 320km Fig.1: skip transmissions involve using the ionosphere to reflect signals from a transmitting antenna to a distant receiver. This diagram shows single skips only but multihop transmissions also occur over ranges up to 2400km. 68 SILICON CHIP it is necessary to ensure that the radio wave emitted by the transmitting antenna is propagated correctly along the path. What many operators fail to realise is that it is very important to determine the distance between the two points as accurately as possible. A deviation from the required bearing by only a few degrees can cause a substantial reduction of signal strength at the receiving point. The distance between two ends of an HF link can be determined using the following equations: CosD = SinA.SinB + CosA.CosB.CosL where D is the angle of arc of the greater circle between the two ends of the link measured in degrees, A is the latitude of the transmitting side, B is the latitude of the receiving side, and L is the difference in longitude. For stations in the northern hemisphere, latitude takes a positive sign and for those in the southern hemisphere, a negative sign. The actual distance between the two ends of the link in kilometres is obtained from the arc length of one degree of the circle, multiplied by the angle D for the circuit: Distance (km) = 40,000D/360 The direction of transmission from the transmitting end to the receiving end is given by this formula: Sin CA-B = (CosB.SinL)/SinD For the reverse direction, the following formula applies: Sin CB-A= (CosA.SinL)/SinD Having determined the antenna bearing, an appropriate frequency can be selected from ionospheric prediction charts of the world for the various seasons. These charts indicate the maximum usable frequency for the particular time of the year. C c,c, c::,c:,c::::, 0 OCN 011) 0 gc:, CICI NON 0<"'> .,....,... QC:,OQ QOC>CI Q C:::, U, .,... C:ti.t'>OO NN(")°"" co ......... Cl Cl 11)00 N NM""' ~ 160 would have been for the F2 layer. Thus, the E, Fl & F2 layers of the ionosphere should all be considered, together with the time of day and temperature. All these factors are used to determine the correct angle of radiation. Antenna polarity c::, c:,c:::,o C, C, "' c:::,c:::,c, DISTANCE 1km) USING M XIMUM FDT'S DISTANCE 1km) USING MINIMUM FOT'S 90 80 ... 70 - 60 "'z< 50 :c ~ ...... . C w ,= 160 "':cw :c 320 2!I 320 E ~ 500 z "' ;;; z "' ;;; 700 800 1000 ~ ::, 40 EXAMPLE OF A 1000km POINT-TO-POINT CIRCUIT 30 ~ 700 800 1000 i:i 1200 :;; 10 4 5 6 7 8 9 10 20 30 40 500 z w ,._, 20 ... "':cw 1500 2000 2500 3000 4000 ~ ::, I,._, 1200 ,= 1500 w z "' i:i 2000 2500 3000 4000 FREQUENCY 1MHz) Fig.2: this general propagation chart is used to determine the maximum frequency range & take-off angle angles for a transmission path. Shown is an example for a 1000km point-to-point circuit (within the rectangle) Fig.2 shows the general propagation chart. The shaded area determines the maximum frequency range and take-off angles for the point-to-point link. Selecting the angle of radiation of the transmitting antenna and the angle of radiation at the receiving antenna are two very important matters relating to the correct selection of antenna type. One method used to determine these angles is the skywave transmission graph, such as the one shown in Fig.3. The scales on the chart indicate the distance between antennae and the distance between reflection points, as well as the height of the reflective RF layer and the take-off angle. A simple example shows how this chart can be used. If we wish to determine the angle of radiation for a path of 1000km great circle distance, we can assume the ionospheric reflection point will occur half way between the two stations. For F2 layer reflections, the effective height can also be assumed to be 300 kilometres. By measuring a straight line between the antenna location (left hand corner of graph) and the assumed reflection point of 300km in height, the angle of radiation for the "take-off" can be read by extending the line to the scale at the top of the graph. For the example shown, the take-off angle is 28°. It should be noted that this angle actually changes with time (according to the ionospheric conditions) and temperature. For example, the E layer, which exists about 100km above the Earth's surface, is primarily active during the day. Hence, the angle of radiation of the signal is lower than it 30 TAKE OFF ANGLE 1°) 20 For long distance communications, the polarity of the antenna is relatively unimportant. When ionospheric paths are involved, the rotation of polarisation within the ionosphere generally has a negligible effect on the performance between vertical and horizontal antennas. Antennas should thus be selected for the highest effective gain at the expected take-off angle. This can be determined without any regard to polarisation, provided that the same kind of antenna is used at both ends of the link. It should be noted, however, that noise, whether man-made or natural, normally tends to become vertically polarised and so receiving antennas using this polarity will be more susceptible to noise pick-up. Horizontally polarised antennas are also preferable because the •angle of radiation can be more easily varied to suit the path requirement. This is done by changing the height of the antenna above the ground. From antenna theory, if a ¼-wave antenna is a ¼wavelength or less above the ground, the radiation is essentially upwards. Raising the antenna further tends to lower the radiation angle towards the horizon. Horizontally polarised antennas are best used at a height of less than one wavelength above the ground or where the normal beam angle is more than 15°. In general, horizontally polarised antenna systems are more useful for 10 _____,0 1200 OO 1400 1600 1800 GREAT CIRCLE DISTANCE Fig.3: this skywave transmission graph allows the take-off & arrival angles to be calculated. By drawing a straight line between the antenna location (left hand corner) and the assumed reflection point (this example assumes a height of 300km), the take-off angle can be read by extending the line to the scale at the top of the graph. OCT0BER1991 69 AIR CONTAINING ...-_..-MOISTURE AIR CONTAINING MOISTURE~- HORIZONTAL VERTICAL Fig.4: vertical (left) & horizontal electrolytic grounding systems. Condensation is formed when moisture in the air is extracted by natural salt contained inside the electrodes. The resulting solution trickles down a bed of coarse granulated metallic salts, thus forming an electrolyte which then seeps into the ground. short and medium range links; ie, for distances of 500-Z000km which may require angles of radiation between 25° and 50°. Vertical antennas tend to have their maximum radiation at lower angles. Electrolytic grounding Because the Earth is not a perfect conductor, the ground has an enormous influence on the actual angle of radiation of the antenna. Conventional methods of grounding are often used. This normally involves burying copper mats or rods in the ground and connecting heavy duty cables between these rods and the equipment in question. An alternative method for electrical and electronic grounding is now available in the form of self-contained electrolytic systems. These systems are designed to create their own earth by producing a reliable and constant supply of electrolytic solution. The electrolytic chemical reaction between the grounding electrode and the earth is enhanced by this solution, resulting in a ground system exhibiting consistently low resistance between the electrode surface and the surrounding earth. Fig.4 shows both vertical and horizontal electrolytic grounding systems. These create a network of "roots" in the soil, thus allowing for the dispersion of RF current into the surrounding earth. Condensation is formed when moisture in the air is extracted by natural salt contained inside the electrodes. The resulting solution trickles down a bed of coarse granulated metallic salts, thus forming an electrolyte. The metallic salts in these grounding systems are claimed to have no adverse environmental impact on the soil. The chemical properties of the electrolyte are similar to that of salt water and just like salt water, the electrolyte is an efficient conductor, with a low resistance to RF ground currents. Breather holes at the top of the copper tube allow the salt within to absorb moisture from the atmosphere, thus forming an electrolytic solution. The electrolyte then seeps out through the weep holes located near the bottom of the system into the surrounding soil, establishing a network 90 Fig.5: the radiation angle for the main lobe of a long wire antenna varies with the length of the antenna. An antenna four wavelengths long, for example, will have a take off angle of 25 °. 80 70 60 I I \ 30 ~ 20 ..... -... 10 J 70 4 5 6 8 LENGTH IN WAVELENGTHS SILICON CHIP 9 10 11 12 of roots which reduces the resistance between the rod and the surrounding earth. Resistance values of 5f.l or less are achievable, even if in high resistivity or dry soils. The advantages of the electrolytic rod system are numerous: low resistance, less corrosion, fewer rods needed, smaller area required and virtually maintenance-free operation. No watering or addition of chemicals is necessary. In addition, the effective service life of the electrolytic grounding system has been extrapolated (as the system was only developed during the 1970s) to well beyond 25 years. This length of service for the electrolyte can be attributed to the low dissolution rate of the salts and the use of copper tubes. In order to determine whether RF currents are equally distributed between antenna and ground, a simple test fixture can easily be made. This "jig" is made usinga toroid (normally powdered iron) capable of operating up to 30MHz. The idea is that either the grounding wire or the single wire antenna feed will be fed through the toroid. A coil consisting of several turns of insulated wire is wound around the toroid and each end connected to a small lamp. The RF voltage induced in the coil will then be sufficient to light the lamp, depending on the RF current flowing in both grounding lead and antenna line. For optimum antenna performance (when energy is equal in both legs of the antenna), the brilliance of this lamp should be the same in each position. Constructors may wish to fabricate two such jigs, one to be inserted in the grounding leg and one to be inserted in the antenna feed leg. In this way, the amateur can be sure that equal currents are flowing in the ground wire and antenna feed line. Note: this approach is only suitable for single wire feed, not coaxial cable. The photo accompanying this article shows the simple construction of this current sensing device. Our sample u5ed a 6.3 volt "PEA" lamp and several turns of PVC coated wire. This arrangement was sufficient to light the "PEA" lamp, even when using a low power 5-10 watt transceiver on the 28MHz band. 1 Long wire antennas There are many types of HF anten- BRAND NEW, AMORPHOUS SILICON SOLAR PANELS, CONSTRUCTED ON IMPACT RESISTANT GLASS For the more serious cost effective applications. This one will almost fully charge a fully discharged 12V.6.5AH This simple "jig" can be used to check that the RF currents are equal in both legs of the antenna. It is made by winding several turns of insulated wire on an iron-powdered toroid & connecting the two ends to a small lamp. get cell in one day! Minimum charging current into a 12V battery. 700mA. Voc: 16V (max) 20V DIMENSIONS: 300mm X 900mm. ONLY Order Solar Panel : SP3 DELIVERY BY SKYROAD EXPRESS sgg 2 WATT-12V SOLAR PANEL nas, ranging from multi-element directional antennas to the simplest long wire type. Those operators who live in urban areas have to compromise regarding the type of HF antenna they use. This compromise may be due to cost and/or size considerations. Practically any antenna will enable an amateur to make good contacts under some conditions of propagation. Perhaps one of the easiest and simplest HF antennas available is the "long wire" antenna. As can be seen from Fig.5, the radiation angle for the main lobe of a long wire antenna varies with its length. Generally, a wire antenna only qualifies as a "long wire" if it is more than one wavelength long at the frequency of operation. As can be seen from the graph of Fig.5, an antenna four wavelengths long will have a takeoff angle of 25°. If the antenna is made longer, the directional characteristics will be changed. Instead of the typical doughnut radiation pattern of a ½-wave antenna, the main lobe splits into various sub-lobes. The longer the antenna, the more the maximum lobe becomes "end-on" in response. A low angle of radiation from a long wire antenna can be enhanced by tilting the antenna down towards the direction of transmission. Further reading (1) "EMC Technology", Vol.6, No 1, Jan/Feb 1987. (2) Grounding Systems Data - XIT Grounding Systems, Lyncole Industries Inc, 22412 South Normandie Avenue, Torrance, CA 90502. Phone (213) 320 8000. (3) Communications International Magazine, September 1990. (4) "Radio Electronics", July 1989. (5) "CB Action" magazine, May/June 1988. (6) ARRL Handbook. SC .1.m:...;. r.~1;:i:.1;~ 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. Can charge 0-12V batteries at approx. 150mA. More than adequate for maintain• ing 12V batteries in cars and boats, or charging batteries in portable appl iances. DIMENSIONS: ONLY , .. ~,.. 150mm X 300mm ,£:-~ ~ Order Solar Panel: SP2 ·'" · DELIVERY BY SKYROAD EXPRESS s29 . 1 WATT-6V SOLAR PANEL Experimental delight! One of these panels will fully charge a 6V-500mA HR nicad battery pack in about 4 hours! You can also connect as many of these panels in series or parallel to produce ..,,,,,,,m,-❖' ~1tti~t~o~~~ c~h~;t,,;e'ltr~gamm Voc: BV (max) 10V lsc: 250mA (max) 300mA Order Solar Panel : SP1 ONLY s12 $ 3 P&P NEED A BATTERY TO CHARGE WITH YOUR PANEL? Based on a " state of the art" 3mW visible re laser diode, and a matching heats ink/collimator assembly. The circuit even has provision for digital switching. Use them for pointers, sights, communications, security, etc. This kit includes the laser diode, collimator, PCB and components, and all the casing : Everything you need to make a complete pointer! PRICE IS REDUCED BY OVER 20% ! $179 + $5 Cert P&P How about our BARGAIN PRICED brand new, industrial grade, 6.5AH sealed GEL batteries, at a fraction of their real value. Yes, 6.5 AMPERE HOURS! Use them in alarms, communications equipment, HE-NE laser power supplies, lighting , solar powered systems, etc. Excellent low temperature performance : 90% of full capacity at deg Limited stock at o c, s34 ONLY Ea. DIMENSIONS: 150 X 95 X 65mm. Weight of one battery is 2.54kg . LASERS are not for kids: DANGER ANY OR AS MANY ITEMS DELIVERED BY SKYROAD EXPRESS TO YOUR DOOR: $10 OATLEY ELECTRONICS · po·sox 89, OATLEY, NSW 2223 . Telephone: (02) 579 4985 , , Fax: (02) 570 7910 OCT0BER1991 71 VINTAGE RADIO By JOHN HILL Two vintage radio museums This month, we're going to digress slightly and take a look at two very interesting vintage radio museums.., Both museums are situated in Victoria and include impressive collections of pre-war vintage radios, plus many other relics from the pre-war era. When I first started collecting valve radios back in 1984 , I found it an interesting and compelling hobby. Although I had engaged in many other hobbies over the years, none were quite as exciting as vintage radio. At the time, I had this wonderful idea to combine my new interest with my approaching retirement. I could have my own radio museum where my entire collection would be on permanent display. In my mind's eye, I could see myself counting the admis- sion dollars as hundreds queued at the door waiting to get in. Who needs Tattslotto? Unfortunately my retirement fantasy will never become a reality. To set up such an enterprise requires a considerable amount of cash and unless a museum is situated in a high density tourist area, it is not likely to be worth the effort or the expense. Where I live (in quiet central Victoria), such a venture would be a financial disaster. The Orpheus Radio Museum caters for a wide range of interests. This photograph shows part of the museum's 1920s collection. Included in the collection are a 1923 2-valve Marconiphone, a 1923 2-valve Crossley, several 4, 5 and 6-valve TRF models, and an early Radiola superhet from about 1925. 72 SILICON CHIP I keep telling my wife that we are shifting to the Gold Coast to set up shop, but she keeps coming up with all sorts ofreasons why we shouldn't go. The most convincing reason is: "where is the money coming from?" But despite my inability to achieve my retirement dreams, other collectors are setting up private museums all over the country. There are doll museums , car museums, clock museums, aircraft muse.urns, and museums displaying anything from farm implements to old bottles. If someone collects it, there will be a display somewhere for all to see. The Catswhisker One of the more recent radio museums to open is at Chiltern, Victoria. "The Catswhisker" radio museum is run by Bob and Marg Adkins and is a cut above the average collection of dusty relics. The name, in particular, is most appropriate for such an establishment and there is a special exhibit explaining the importance of the catswhisker in those bygone days of early radio. Such an explanation is necessary today because so few know about the old style crystal detector and its catswhisker. Bob's museum is in his back yard and is housed in a large well built shed. The building is lined and insulated and is a comfortable place to be regardless of the weather. Items on display mainly include radios from the v~lve era plus quite a few early phonographs. Most of these exhibits are in working order and have been lovingly restored. Those that are not working at least look the part and, collectively, it is a very good display of radios and early sound equipment. The Catswhisker has an excellent collection of radios from the 1920s era. They range from simple crystal ' ·t ,. _I(". : ,:,,·;.•,,. ·-r.:?-·_i:. ·-- · t-_ These vintage radios are just a few of the many radios in Bob Adkin's collection. They are, from left: an Airzone, an Astor Mickey Grand and a Tasma. Bob Adkins, owner of the Catswhisker museum in Chiltern, Victoria. The Catswhisker houses an excellent collection of old gramophones, radios and movie posters. sets to some very stylish 5 and 6-valve TRF sets that were typical of that period. Many of these old receivers are accompanied by the usual horn speaker and the 1920s collection really looks the part. Perhaps the best aspect of this section of the museum is that these valuable items are on display in a huge glass-fronted cabinet. The cabinet is illuminated from the inside and its contents are neatly displayed with a few old household ornaments which provide added appeal. The radios in the 1920s cabinet are arranged in three tiers and together make up one of the most impressive displays I have seen. It often grieves met to see a valuable collection gathering dust and slowly deteriorating due to neglect and improper storage. Bob's big glass cabinet solves many problems and its contents are not only well preserved but very well dis played. The Catswhisker's valve collection is also under glass. Once again , these items are not only well displayed but The 1920s cabinet at the Catswhisker vintage radio museum includes this old Harness reflex receiver (left) and an elaborate home-made crystal set. are well protected from souvenir hunters and the like. Although it is great to have working displays for all to touch and use, some museum relics need to be out of reach - particularly anything that is easily broken. But Bob Adkins_doesn't have everything behind glass. Most of his radios, apart from the 1920s collection, are out on open display and in working order - and Bob has some very interesting old sets in his collection. Two of the more noteworthy receivers are a stylish old "Majestic" and a "Sonora" from the late 1920s. These very large sets are typical examples of some of the up-market receivers of those times. Another rare piece is an "Astor Mickey Grand" which is of 1935 vintage. Many of the more everyday mantel and table model radios are displayed in the museum on shelving around the walls. Also on show is a range of old gramophones, including an early "Columbia" and an "Edison" cylindrical. These machines are fully operational and visitors to the museum can compare between the recorded sounds of yesteryear and those of today. Bob Adkins 's museum also boasts an incredible collection of old movie posters and these add considerable interest to the museum. They are very colourful too , and give the place quite a lift. The Catswhisker is not a stuffy room · filled with dusty junk. It houses a collection of interesting items which are nicely arranged in pleasant surroundings . The museum is open on Sundays and public holidays , or by OCT0BER1991 73 An extensive valve collection is also on display at the Catswhisker museum. These date right back to the early days of radio and include many odd and interesting types, some of which are now virtually unobtainable. special arrangement, and is situated at 1 Gaunt Street, Chiltern - phone (057) 261233. It is well worth a visit if you are passing that way on your next holiday. Orpheus Radio Museum The Orpheus Radio Museum at Ballarat, Victoria is also well worth a visit. This particular museum has been open since July 1987 and many thousands of visitors have been through it in that time. Like the Catswhisker, the Orpheus museum has similar displays of early gramophones and radios, with the added attraction of 3BA Ballarat's original transmitter. Also included is a sizeable collection of old cameras and early sound recording equipment. Amongst the latter is a wax cylinder "Dictaphone", a wire recorder and a reel to reel tape recorder with a clockwork motor. The museum has been dedicated to Warne Wilson, the founder of 3BA, by his grandson, Richard Wilson. Richard runs the museum in conjunction with a modern electronics factory where a range of products is produced under the "Atron" tradename. Orpheus is a very significant name for the Ballarat Radio Museum, as Warne Wilson manufactured radio receivers in the 1920s under the "Orpheus" brand name. Orpheus (from Greek mythology) was given a lyre by his father Apollo. Upon mas- There's nothing like an old crystal set to bring back memories. This particular receiver in the Orpheus collection has a built in lightning arrester. 74 SILICON CHIP tering the lyre, his voice and music were truly perfect and this apparently also applied to Orpheus radios. There are several working exhibits at the Orpheus museum, the most fascinating of which seem to be the old crystal sets. As 3BA's transmitter is about 1km away, crystal sets work well with a small aerial. Many museum visitors obtain hands on experience adjusting the crystal detector to find that elusive "good spot". These working relics from the past attract a good deal of attention. Other working exhibits include the gramophones and the "Sounds of the Twenties", where a tape of 1920s radio program extracts and music is played through an old Amplion horn speaker. Such a working display gives visitors to the museum some idea of the toneless reproduction of early loudspeakers and how much they improved with further development over the years. 3BA's original transmitter is interesting in that its output rating was only 50 watts. Today, where 2kW is minimal for commercial stations and most ABC stations run 50kW, 50 watts sure sounds a bit feeble. No wonder everyone had a big aerial mast in their backyard back in the old days. There are many other pieces of equipment from 3BA's past, including the "Liberty Chimes". Remember the days when all radio announcements were preceded by chimes? These melodious sounds put a smile on many a face because it instantly brings back memories of long forgotten broadcasting techniques. The Orpheus display of early ra- This 1910 Columbia gramophone is part of the Orpheus display. Others include an Edison Cylindrical and a Diamond Disk. 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. Also on display at the Orpheus Radio Museum is this assortment of disc, wire and tape recorders from 3BA's past. The tape recorder at centre front is interesting in that it has a clockwork motor to drive the reels. dios is particularly good and many well preserved receivers and speakers from the 1920s era are on show. The Orpheus Museum has no movie posters on its walls but it does have many old photographs from the past. These include early amateur radio stations, old radio advertisements and portraits of famous radio pioneers such as Hertz, Marconi, Armstrong and de Forest. When one thinks of radio museums, one usually thinks of receivers and equipment from the 1920s and 1930s. The Orpheus museum has a good selection of these items. In conjunction with the museum, Richard Wilson also operates a mail order vintage radio spare parts service. This service offers a good supply of radio and TV valves, high voltage electrolytic and polyester capacitors, and numerous other vintage radio bits and pieces. Kits for 1 and 2-valve battery receivers and crystal sets are available, as well as numerous publications. The Orpheus Radio Museum is open seven days a week and is situated at the corner of Ring Road and the Western Highway, Ballarat- phone (053) 34 2513. The postal address is: RSD B98, Ballarat, 3352. Both of the museums mentioned in this article confirm the growing interest in vintage radio. Like vintage motor cars, vintage radio has a considerable band of followers and new devotees are joining the throng daily. 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 catalogue. WANTED - Valves, Radios, etc. purchased for CASH Call in to our Showroom at: 51 Chapel Street, Windsor,Vic 3181 PO Box 1116 Telephone: (03) 529 5639 UV PROCESSING EQUIPMENT KALEX LIGHT BOXES euv2 Exposure Area 40cm x 27cm $650.00 • Portuvee 4 Exposure Area 25cm x 14cm $225.00 3BA's original transmitter is now an important display item at the Orpheus Radio Museum. The 50-watt transmitter was commissioned in 1930 and was in service for six years before being replaced with more modern equipment. But unlike vintage cars, radio collecting is a relatively cheap hobby that most people can afford to indulge in. What's more, there are still lots of old sets around to collect, provided you're prepared to look for them. SC • Portuvee 6 Exposure Area 43cm x 40cm $625.00 3M Scotchal Photosensitive Riston 4600 PCB Matera! All prices are plus sales tax if applicable 40 Wallls Ave East Ivanhoe ' VIC. 3079 (03) 497 3422 (03) 497 3034 Fax (03) 499 2381 ELECTRONIC COMPONENTS & ACCESSORIES e SPECIALIST SCHOOL SUPPLIERS OCT0BER1991 75 I PRODUCT SHOWCASE I for all voltage, current, capacitance and resistance measurements but is disabled for functions such as frequency and transistor hFE· There is also a data hold function and the meter will function as a logic probe, with audible accompaniment. The meter is supplied in a soft plastic carrying wallet, comes complete with probes and software disc, and sells for $215.00. See it at your nearest Dick Smith Electronics retail store. Handy logic tester from Electronic Solutions 31/2-Cligit DMM has RS-232 port Multimeters continue to evolve as truly "multi" instruments, so much so that it is difficult to choose between a plethora of features. Well, here is multimeter with special appeal for those who would like to use their multimeter in conjunction with a computer. Imagine being able to leave a piece of equipment for long term monitoring by your multimeter and have your computer record the time of any unusual readings, as well as the readings themselves. This unit does just that, by virtue of its RS-232 output lead and the accompanying software provided by the retailer, Dick Smith Electronics. In other respects, the Dick Smith Electronics Q-1570 is an unusually full-functioned multimeter with 30. ranges covering AC and DC voltage and current, resistance, transistor hFE, capacitance and frequency measurements. The 20-step bargraph operates Tower computer case with power supply Contemplating building your own 386 or 286 machine? If so, you will want to consider this attractive mini tower case from Rod Irving Electronics. It comes complete with a 200 watt switchmode power supply with the usual 5V and 12V rails. It can take one 3.5-inch and two 5.25-inch drives (hard or floppy) and has buttons for turbo and reset, as well as a keyboard lock. Priced at $325, it is good buying from Rod Irving Electronics, 74 Parramatta Road, Stanmore NSW, or from their Melbourne stores. 76 SILICON CHIP Have you ever built a circuit which didn't work, then later found out that your circuit was not at fault but that one of the logic chips you used was faulty? Well, this is for you. The Picker20 handy tester tests virtually all logic chips from the TTL 74 series, CMOS 40 series and CHMOS 45 series, as well as the DRAM 41 series and the DRAM 44 series. The unit has a dedicated microprocessor on board that tests all functions of each chip when placed in the ZIF (zero insertion force) socket. Even if you 'don't know what type of logic device it is (such as when the label isn't readable), the Handy Tester will be able to give you a good idea of the chip and whether it is functional. The tester is powered by a 9V battery or external plugpack. It has a 1line 16-character display and does a self-test each time it is turned on. The unit is extremely easy to use and retails for $395. For more information, contact Electronic Solutions, 2/5 Waltham St, Artarmon, NSW. Phone (02) 906 6666. Gender changers for computer cables No matter how neatly you start off, eventually your computer system will acquire add-ons and extra cables. Inevitably some of the cables will be incompatible, requiring you to mate up to male plugs for example. This is where these neat and compact gender changers come into the picture. Consisting of two female D sockets back to back, they enable two male plugs (or male plug and socket) to be connected together. Both 9 and 25-pin versions are available for $8.50 each from David Reid Electronics, 127 York Street, Sydney 2000. Phone (02) 267 1385. New solvent for cleaning PC boards . Hycal Electronics has released a new solvent suitable for cleaning PC boards. Called Hycasol, the new solvent is claimed to be safe to use with most electronic components such as ICs, resistors, capacitors, trimpots and PCmount connectors. Supplied packed in 500ml bottles, Hycasol is based on Trichlorethane which is non-flammable but must be used in well ventilated areas. The normal way to clean a PC board would be to pour some Hycasol into a suitable flat dish, brush the solvent on the underside of the board and let it drain back into the dish. Repeat the process until all the Labtech audio oscillator/frequency counter Included in the range of test equipment from Altronics is this Labtech 4digit digital audio oscillator/frequency counter. It generates low distortion (0.5% harmonic distortion or less) sinewaves and square waves over a frequency range from 20Hz to 200kHz. Maximum output is 5 volts RMS at no load, or 2.5V RMS into 600 ohms. A continuously variable control affords greater than 50dB attenuation in addition to pushbutton selectable 10, 20 and 40dB steps. The frequency range is selected in four ranges with a dial to allow continuous frequency selection within each band. flux is removed from the board. The solvent can then be poured back into the bottle for later re-use. The board should be left to air dry for about 10 minutes. Hycal Electronics has appointed Jaycar Electronics as their sole retail outlet. For wholesale buyers wanting Hycasol in 5 and 20-litre containers, enquiries should be made to Hycal Electronics, Unit 4/62 Great Western Highway, Parramatta 2150. Phone (02) 633 5897. As a frequency counter, the Labtech offers a bandwidth of10Hz to 1MHz with an accuracy of 0.01 % ±1 count, with a maximum input voltage of 150 volts peak-to-peak. Price of the Labtech oscillator/ frequency counter is $480 from Altronic Distributors Pty Ltd, 174 Roe Street, Perth WA 6000. Phone (09) 328 2199. Intelligent RS232 card supports Unix The PC COM 4-port adapter provides four asynchronous serial communication ports (RS232C), which link a computer and serial peripheral devices such as modems, serial printers, plotters and mice. The adapter may be configured with up to four individually addressable RS232 ports for any IBM PC/XT, PC/AT, PC/386 or compatible operating under MS/DOS, POSITION VACANT Altronic Distributors is looking for a Sales Assistant to the NSW State Manager for their wholesale division. The position involves Internal Sales by assessing customer needs and has excellent long-term career prospects. The successful applicant: • must be an enthusiastic, motivated person; • must possess a current driver's licence; • must have a natural sales and organisational ability and be able to work with minimum supervision. A good general knowledge of components would be an advantage. If you are aged 18-24 and meet these criteria, phone Colin Fobister on (02) 417 8938. Altronic Distributors, Unit 9, 1 Short St, Chatswood, 2067. OCTOBER1991 77 or any other multi-user system such as PC-MOS/386, Concurrent DOS, XENIX/UNIX or PICK. The adapter has two modes: compatible and enhanced. In compatible mode, it takes the place of the standard serial ports (COM1 and COM2), whereas in enhanced mode, the four ports co-exist with the standard ports. The card is address and interrupt selectable and is AST Fourport/XN compatible. The driver (PC COM) is a high performance, easy to use device driver that takes over communication between the . CPU and each port. It supports 1/0 command driven features as well as C and PASCAL language library routines to link user programs. The software comes with diagnostic, file transfer and virtual terminal programs, as well as library routines to control the device driver, written in Turbo C. A setup program is also included to configure the card on power up. The retail price is $149. For further information, contact Electronic Solutions, 2/5 Waltham St, Artarmon, NSW 2064. Phone (02) 906 6666. Anti-glare filter for computer monitors Do you have a problem with glare or reflections from your monitor? Many offices are very brightly lit or have sunlit windows which can make it very difficult to use a computer monitor. The answer is to use one of ANTRIM TOROIDAL TRANSFORMERS • • • • 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 PTY LTD 90 George St, Hornsby, NSW 2077. Phone (02) 476 5864 Fax (02) 476 3231 78 SILICON CHIP these filters from Rod Irving Electronics. Suitable for just about all 12-inch and 14-inch monitors, the filter is a very fine mesh woven from black nylon fibre. It is claimed to reduce glare by 90% and ultraviolet and daylight reflection by 85%. We can certainly vouch that it cuts reflections to a minimum. The filter comes with double-sided adhesive tape for attaching it to the front of your monitor, or may be fixed with hanger brackets. It is priced at $14.95 from Rod Irving Electronics, 74 Parramatta Road, Stanmore NSW or from their two Melbourne stores. LCR digital multimeter from Altronics This 3½-digit digital multimeter has 30 ranges and does just about everything you could ask for in a multimeter. Going round the dial, it has five ranges for capacitance, eight resistance ranges, diode and continuity testing, transistor testing, five current ranges and five voltage ranges for AC and DC. It features a large LCD screen with 0.5-inch high digits, low power consumption (powered by a 9V battery) and a high-impact yellow plastic case. It is priced at $149. Also available is a handy plastic carrying case which has a separate storage compartment for the test leads. It is priced at $12.50. For further information contact Altronic Distributors Pty Ltd, 174 Roe Street, Perth WA 6000. Phone (09) 328 2199. For Features, Price and Performance, there's no other choice [fualJj 13 . ,'!/ ..,,.- ~t I.1~1· -;- DM8243 Multimeter with Frequency Counter DM8135 Multimeter with Bargraph • 31/2 digit large LCD display • Memory for relative measurements • Data hold function • Diode and Transistor testing • • • • 4 1/2 digit large LCD display Measures capacitance 200kHz frequency counter Diode and Transistor testing Gotta Gatta 0S7020A 20MHz & 0S7040A 40MHz Oscilloscopes DM8433 Multimeter with Thermometer • 3 1/2/digit large LCD display • Measures capacitance • Measures Temperature -20 to +15(}'C DM6335 Multimeter fits your shirt pocket • 3 1/2 digit LCD display • Memory mode for relative measurements • Data hold function • Slim,compact construction GoldStar 0S8020R • High sensitivity- 1mV/div • Stable low drift design • 8 divisions of displayed dynamic range with accurate distortion-free waveform measurement • Special TV sync separation circuits for measurement of video signals • Delayed sweep function (DS7040A) • ±3% accuracy • Convenient XY operation for measuring phase differences between two waveforms • Variable sweep control incorporating xio magnifier • Uncal and trigger warning lights • TV-V & TV-H triggering • Trigger hold-off • Includes TWO x1Jx10 switched probes Readout Scope • Cursors for direct measurement of waveform voltage, time and frequency • 20MHz bandwidth • 1mV max sensitivity • Similar performance to OS702GA ELMEASCO Instruments Pty. Ltd. Australia's Leading Test & Measuring Instrument Company Contact your nearest Elmeasco Office for name of your local supplier and special pricing if you mention this magazine Tel : (02) 736 2888 Fax: (02) 736 3005 NEW SOUTH WALES Tel : (03) 879 2322 Fax : (03) 870 8972 VICTORIA Tel : (07) 875 1444 Fax : (07) 277 3753 QUEENSLAND Tel : (08) 344 9000 Fax : (08) 269 6411 SOUTH AUSTRALIA Tel : (09) 470 1855 Fax : (09) 470 3173 W. AUSTRALIA REMOTE CONTROL BY BOB YOUNG The military applications of radio controlled aircraft Not all radio controlled planes are built for fun. Some are built for military surveillance and aerial photography, and some are used for target practice for gunnery and missiles. One of the most interesting periods of my career in R/C modelling came through my involvement in the military applications of R/C models. This began with the development of a system for training the operators of shoulder launched missiles, which subsequently led to the Silvertone Weightlifter (Fig.1) and the De Havilland Enmoth. These mini RPVs ultimately found their way into various Government Departments and could form the basis of a separate story. However, as a result of the shoulder launch project, I became known in military circles which then led to my involvement with the All Arms Air Defence project. This was a very exciting project and forms the basis of this article. As a result of experience gained during the Vietnam War, the West learned from bitter experierice that small bore weapons could inflict seri- ous damage on modern high speed ground attack aircraft. Although they rarely came down as a result -of this damage, it is almost impossible to put a bullet through the modern military aircraft without damaging something -usually a very expensive something. As a result, aircraft were constantly grounded and repair and maintenance problems became a major issue. With these lessons in mind, it was decided that All Arms Air Defence would be introduced into the training curriculum of the Australian Army. The project started out in a small way using the well-known Mini Sticks which we supplied and these were flown by Danny Mazlowitz, a keen modeller and a member of the regular army. During the first shoot, these proved to have serious shortcomings, not the least being that they were far too slow. In any sort of headwind, the closing speed was pathetic (and we had to fly in all conditions regardless of weather, for once a shoot was scheduled that was it) . So we soon decided that we needed a better aircraft. Development of the MAT-DF Fig.1: the Sivertone Weightlifter was developed for the Australian Army as a target aircraft for shoulder launched missiles. 80 SILICON CHIP The MAT-DF (Model Aircraft Target - Delta Foam) concept grew out of the experience gained with All Arms Air Defence Targets of conventional styling and construction. In common with most targets of that time, the original Silvertone target was constructed of balsa and followed the normal MAT layout. Again in common with all targets of that type, the problems of fragility, lack of adequate speed envelope and the high number of man hours (cost) per airframe were painfully obvious. Fig.2: the MAT-DF delta-winged target aircraft. It was driven by a rear-mounted engine & was made from moulded polystyrene. Note the lack of a rudder. As these problems were similar to those encountered by all model flyers, we decided to investigate a type of model utilising simple, low cost construction techniques which would fulfil both military and commercial requirements. From the very beginning, it was decided that an all out attempt at a throw away aircraft was the most suitable approach to the problem of the MAT requirement. Time to repair was a major cost factor in target aircraft. Also, holding up a shoot resulted in 40 impatient soldiers leaning over your shoulder muttering obscenities; definitely a great incentive to reduce repair times at the design stage. Thus, we proposed a completely moulded airframe which would require very little finishing work and if broken could be discarded and replaced at less than repair cost. Without any doubt, the scales are heavily loaded in favour of any proposal which can fulfil the role with a minimum of cost due to the short lifespan of the finished item. Careful analysis of the crash damage in the conventional tractor MAT design revealed that the motor was a major cost item and also a constant source of trouble in subsequent operation. With the tractor layout, the motor is subject to extreme punishment and the problems of bent crankshafts, dirt ingestion and broken components can pass unnoticed in the field and lead to subsequent unreliability and therefore loss of train- ing time. These problems can be largely overcome by using a rearmounted motor. Also, the risk of injury due to out of control targets is much reduced with the motor in the rear. The pusher is also much more efficient and the big plus is that there is no burnt castor oil on the airframe, which results in much better repair conditions. The repair issue was the all important consideration in this whole project. With this in mind, the final design very quickly firmed up as a 3-channel pusher delta (Fig.2 & Fig.3), for this layout lends itself well to moulding and repair techniques. The final design thus resolved itself into a 3-piece expanded polystyrene mould set with a wingspan of 93cm and fitted with an O.S. 40 FSR, retimed to run in reverse, in order to use standard props. The final weight when new (unrepaired) was 1.5kg, but the repaired weight could go as high as 2.5kg. Three-channel radios were used on throttle and elevons, the latter driven via a specially designed electronic mixer. Rudder control was not fitted. The big problem with the pusher layout is the negative stability introduced at high angles of attack. This is particularly true at slow speed and, in particular, during hand launching. This was to be a vulnerable point, for the flying sites used called for hand launching and a much repaired model suffered a dramatic weight increase. In the hands of a tyro pilot, launches became a real health hazard for the model. The problem stems from the fact that at low speed and the subsequent high angles of attack, as experienced just after a hand launch, the centre of drag is well above the thrustline and any increase in power tends to lift the nose even higher, thereby increasing the drag even further. At this point, the model starts to sink towards the ground at which point the tyro pulls in up elevator and lifts the nose higher still. This results in more drag and more sink, and so the situation very quickly gets out of hand for the inexperienced flyer. The answer is simple - a touch of down elevator cures the problem immediately. But here is the rub: inexperienced pilots do not like giving down elevator when three feet off the ground. The problem also manifested itself in go-arounds where the aircraft seemed to absorb all the power you could give it without any increase in airspeed. It was a peculiar feeling but again any increase in throttle had to be accompanied by a touch of down elevator. Once the thing got on the step, it flew as straight as an arrow and was very pleasant to fly. However, this problem was to give us some grief when the less experienced army pilots took over the project. Flying sequence As stated previously, after several sessions with conventional airframes, the shortcomings soon made themselves felt. As a result we approached the Army with the view of developing a more suitable airframe at our own expense. I placed this stipulation upon the project in order that I could sell the finished item commercially without obligation if it proved successful. This was agreed to and unfortunately introduced an unexpected side effect into the project. A prototype was produced and test flown in an actual shoot. This prototype model flew absolutely brilliantly for it weighed only 1.5kg. Very fast (180km/h plus), it was voted by gunners who had trained on Mirages in combined operational exercises as the most realistic target they had put their sights on. It was also easy to launch because of the light weight and very smooth to fly. It could not however stand the wear OCT0BER1991 81 Fig.4: a rear mounted motor is an advantage in a target aircraft since it is not as susceptible to impact damage when the aircraft is shot down. and tear of operational flying, particularly emergency landings in scrub brought about by the fact that the gunners would do nasty things like shooting the motor clean off the airframe, or putting a bullet straight through the fuel tank. This was to be a constant source of worry duri_ng the whole project. You never knew what was coming next and although the aircraft flew very well with the motor shot off and could be landed safely (all that happened was that the centre of gravity moved forward), a bullet through the battery pack was a pretty tedious affair. Nor did you ever get used to that awful feeling that came with an abrupt loss of control - no warning, just instant emergency. You got pretty good at nursing home wounded birds. As a result, we did many, many outlandings, most completely out of visual contact, behind trees and the like. As you can imagine, wear and tear was a very real problem. I made a serious error in beefing up the mouldings with fibreglass and heavier and stronger wood in order to prolong the life as much as possible. In so doing, I completely destroyed the project, for we lost the throwaway concept. The heavier airframes were more expensive and took much longer to build, hence there was a much greater reluctance to throw them away (especially since I was paying for them), and so they were repaired and just got heavier and heavier and more and more difficult to launch. This was the real trick in this project 82 SILICON CHIP and that involved striking a balance between wear and tear and the throwaway concept. The new models did however withstand crashes and wear and tear infinitely better. Returning to the prototype, we flew with that model for about six hours on the first day, nursing it along through various trials and tribulations until the inevitable - a bullet straight through the Rx . Those little bits of steel used to do terrible things to the radio reception. Now I must point out here that most models did not go this long before being brought down . We were using 1 in 3 tracer which is pretty hard on the gun barrels (Brens and M60's) but did give the instructors a very clear picture of the pupil's progress. Also, eight guns firing simultaneously gave a very interesting and somewhat spooky visual effect. As I was flying from behind the guns and flying head on into the guns, I could thus view the position of the aircraft in relation to the tracer stream and therefore adjust my position to stay out of the worst of it. In the actual shoots, I was ordered to fly a straight line and this increased the hit rate dramatically. In the test flying when I was flying evasively, we fired about 10,000 rounds before we brought the model down. Flying nonevasively, we averaged one hit in 600 rounds and it took six hits on an average to bring the model down. I found the experience of flying into a stream of tracer quite eerie and thought back on airmen who had to actually face this from inside the air- craft. I am glad I missed the experience for it is one I can live without. One interesting phenomena that I did notice was that the shock wave from the nose of the bullet would jolt the airframe in near misses. This effect is used in sonic miss detectors and it is surprisingly strong. When the aircraft started to rock you knew someone was getting too close and a quick application of control would ease the model out of harm's way; usually! Returning now to the prototype, when it did finally crash, that was it. The lightweight construction just allowed it to disintegrate and it was not repairable on the field. However, it did fly again in the next session. So ended day one of the Delta project. Our next session was with the six beefed up airframes. From the outset, we had difficulty in launching. That extra 500 grams made all of the difference for it was only supported by 511 square inches of wing (the small wing was forced on us by the limitations in the size of the foam moulding equipment) . It also took me a while to wake up to the trick of applying down elevator to stop the power absorption. Once this was mastered, it was no problem. Furious shooting Shooting started at a fast and furi ous pace. The mission profile called for a racecourse track starting 600-700 metres out in front of the guns and flying directly towards the guns which were eight abreast on the firing point. I was to cross over the guns at about 20 feet altitude. I felt this was a little dangerous and pointed this out to the officer in charge. I do not think he realised what I meant for he just asked me to carry on. All proceeded smoothly with the usual bullet holes being patched and fuel tanks being replaced etc, until on one pass a bullet passed through the bottom of the left hand wing and struck the elevon pushrod smack in the middle. As this was only 16 gauge wire, it immediately kinked into a "V" and applied full "up" on left elevon. Normally this would not be too serious and the model would have just spun into the ground. As it happened however, it was the last round out of one of the guns and the model was directly in front of the firing point and at an altitude of only 20 feet. Fig.4: the Falcon "A" target aircraft was a fibreglass & foam version of the Senior Falcon & was very popular with the Army pilots. long as everything was working, the It completed one half roll and plowed into the ground 20 feet in rough patch of ground available for a front of the officers ' table and skidded landing area was more or less satisstraight into their feet, amid a great factory. It was small but reasonably cloud of dust. With that, the O.C. clear. The belly skid stopped the jumped up and demanded to know model in a very short distance ana why I crashed into their feet? What mostly with no damage. could I say? The incident impressed It was when the aircraft was damme however, for I realised that had aged in flight that the problems bethe bullet passed 3mm either side of gan. The most common faults were the pushrod, the model would not strikes to the engine or fuel system, have crashed. In such a random, horwhich meant an engine loss over impossible terrain, mostly out of sight to ribly indeterminate way do men die or become maimed in times of war. the pilot. The aircraft suffered badly With that little example behind us, here and the weight gradually spiralled after constant repair, with the conwe had no more head on approaches sequent increase in problems at hand and all profiles from that point on were oblique. There was still that ele- launch. Danny and I seldom had problems ment of danger however and one had to be constantly alert for any type of here but the less experienced Army pilots who flew the last missions had emergency. After weeks of this , the great difficulty and the project was pilots got very good at emergency procedures. ended at that point. You never knew where the hits took However, the more robust airframes place and if a part weakened by a hit were staggeringly strong. The later went unnoticed, it could let go unexversions, with their fibreglass cladpectedly. On one occasion, Danny was ding, were 40% recoverable even afabout to start the motor when someter a full throttle dive into the ground, one pointed to the prop and there which they did, time after time (reright in the middle of one blade was a · coverable being defined as field reperfectly neat 7.62mm hole, clean as pairable). The Delta configuration gave a whistle. Post flight inspection had immense strength due to the thickto be thorough. ness of the wing and the shape of the However, it was the outlandings fuselage. The nose used to crumple, that took their toll of the models. As but that wa·s it. Splice on a new nose and away you went. The motors were never marked and we needed nothing in the way of motor spares except in the case of bullet strikes. All in all the project was a success. The target was very realistic and the repairability of the airframes good. However the hand launch problem plagued us to the end and subsequently turned the Army pilots off the Delta configuration. Yet had we stuck to the original concept of a true lightweight throwaway model or even been able to increase the original wing area, the project would have been a complete success. As it was, once the moulds were made it was too late to change. The problems came about by allowing outside factors to intrude on the original design parameters. I also wondered at a much later date about more downthrust. Would this have helped? Would it have upset the flying characteristics. We never knew, for once the project lapsed I never flew another of these aircraft. This was the thing that I liked most about the military work. It was so demanding. You had to be able to develop a system for all types of pilots. The army pilots were not modellers and did not have that wide background that comes with years of flying. They had attended the official courses and whilst well trained and quite capable as flyers , they just lacked that extra something which comes with years of experience. The Falcon We subsequently went on to develop the Falcon "A", a fibreglass and foam version of the famous Senior Falcon. This model was very popular with the Army pilots and we deliveredmany of these models which were used for All Arms Air Defence Targets, amongst other things (Fig.4) . However to me, they just did not look right after flying what to my mind was the ultimate All Arms Target. Through the ring sight, the MAT-DF looked for all the world like a full size Mirage as it came boring in on us from virtually out of sight. The gunners loved it even though it was hard to hit - unless you were a crack shot, that is. I remember one gunner who was pulled off the guns after bringing down two aircraft in two bursts. I guess they figured he needed no further training! SC OCT0BER1991 83 LEDS WE HAVE EXPANDED OUR COMPUTER LEAD RANGEi ~I== A& ~I== QUALITY 3mm LEDS 1-9 1-9 10-99 100+ "~"~"·~ 10-09 100+ 210140(R) $0.15 $0.12 $0.10 210141(G) .. $0.20 $0.18 $0.15 Z10143(Y) .. $0.20 $0.18 $0.15 210145(0) .. $0.20 $0.18 $0.15 QUALITY 5mm LEDS BNC PANEL SOCKET 1-9 10+ 100+ P10516 $2.50 $2.25 $1 .50 nc. . BNC CRIMP PLUG 1-9 10-99 100+ 210150(R). $0.15 $0.12 $0.10 210151(G). $0.25 $0.20 $0.18 210152(Y) .. $0.25 $0.20 $0.18 .,_.. ---- .._. FLASHING LEDS RED 5mm Z10159 P10530 $3.95 $3.75 $3.00 ( ~ ,~.1J...).J,-1 BNC SOLDERLESS TWIST ON PLUG Designed to tr,ansmit at ··, 40kHz (L 19990) & recieve at 40kHz (L19991) withup to 2QV 1/P on the transmitter. lhese units can't be heard so are ideal for TV remote controls, water level dectectors, burglar alarms, motion dectectora & infonnation carriers as they can be either pulsed or used In a continuous wave mode. Transmitter 1-9 10+ L19990 ....... $2.95 $1.95 Receiver L19991.. ..... $2.95 PLEASE RING TO CHECK AS NEW LINES ARRIVE DAILY. NULL MODEM CABLE M/F................. $19.95 NULL MODEM CABLE M/M ........ ........$19.95 MONITOR EXTENION LEAD 15 PIN HIGH DENSITY $29.95 DB9 M/M 5.0 METRE ............................ $29.95 DB9 M/F 5.0 METRE .............................. $29.95 2 WAY................ $59.95 4 WAY................ $69.95 MONITOR& KEYBOARD SWITCH BOXES only $69.50 AT SERIAL CABLES DB25M/DB9F 2.0 METRE ...................$19.95 DB25F/DB9M 2.0 METRE ....................$19.95 DB25M/M 10.0 METRE...... .................$39.95 DB25M/F 10.0 METRE .........................$39.95 DB25F/F 10.0 METRE ......................... $39.95 RECTANGULAR LEDS Save a fortlfflCI on expenaive throw away batteries with theae quality Nlcada and Rechargera I Size AA 450mAH 1-9 10+ 100+ RED ~ 15e GREEN ~ 15e YELLOW ~ 15e 12e ORANGE 20e 15e 12e 1-9 10+ $2.95 $2. 75 100+ $2.50 SlzeC 12AH $9.95 $9.50 SlzeD 12AH $9.95 $9.50 CANNON TYPE 3 PIN CHASSIS MALE 1-8 10-88 100+ P10962 $3.50 $2.95 $2.50 CANNON TYPE 3 PIN LINE FEMALE 1-8 10-88 100+ P10964 $3.95 $3.50 $2.90 ~ -- --- DB25 CONNECTOR SPECIALS n nnnnnnnn, 1-8 10+ P10880 DE9P $1.00 $0.90 P10885 DE9S $1.00 $0.70 P1oae1 DA15S $1.00 $0.70 P10892 DA 1SC $1.00 $0.90 P1oae5 DA1SS $1.00 $0.90 P10902 DB25C $1.00 $0.80 P10904 DB25P $1.00 $0.90 P10905 D825S $1.00 $0.90 LOW PROFILE IC SOCKETS Save a small fortune on these "Direct Import" low profile IC sockets! PCB mounting solder tall. All tin plated phosphor bronzo or berrylllum and dual wipe for rollablllty. 10-99 100+ P10966 $4.95 $4.50 $3.50 P1osso 8 pin 15t 12e 10, P10S60 14pin 20e 1se 15e P1056516pin 20e 1se 1se P10S6718pin 30e 25e 22e P10s6a 20pin 35e 30e 25e P10569 22pin 35e 30e 26e P1os10 24pin 35e :ioe 2se P1os12 28pin 45e 35e 30e P1os1s 40pin 45e 40e 35e ~10+ $9.50 $8.00 $10.00 $9.50 $8.50 $8.00 $9.50 $8.90 1 -9 10-99 1-9 100+ P10960 $4.50 $3.50 $2.50 WIRE WRAP IC SOCKETS Th• .. quality 3 levol wlro wrap sockets are tin platod COMPUTER CABLES 9--. • Six conductor 11hlelded computer Interlace cable. W12670 • CIC6 6 con. 1-9M 10M+ 100M+ $1.30M $1.10M $1.00M W12672 • CIC9 9 con. phosphor bronze. P10579 8pin $1 .50 $1.40 P10580 14pin $1.85 $1.70 P10585 16pin $1.95 $1.80 P10587 18pin $1.95 $1.90 P10590 20pin $2.95 $2.75 P10592 22pin $2.95 $2.70 P10594 24pin $3.95 $3.50 P10596 28pin $3.95 $3.50 P10598 40pin $4.95 $4.50 10+ 2155 240V 6-15V 1A M12155 ......... $8.95 $7.95 2156 240V 6-15V A2 M12156 ........ $13.95 $12.95 CANNON TYPE 3 PIN LINE MALE 1-9 We have a great range of panel meters at great prices! 010500 MU45 0-1mA $9.95 010502 MU45 5Cll50uA $9.95 010504 MU45 0-100UA $9.95 010533 MU52E 0-SUA $12.95 010538 MU65 0-50uA $12.95 010540 MU65 0•1mA $12.95 010550 MU650-100UA$12.g5 010560 MU650-20V $12.g5 1-9 10+ 100+ CANNON TYPE 3 PIN CHASSIS FEMALE 1-9 t·i()O(-: 100(■J 10+ • Plug P12200 $3.95 $3.00 • Socket P12201 $3.95 $3.00 L FANS n~ =:) 12V DC FANS Oeecrlption 1-9 10+ 7805UC 7812UC 7815UC 7905UC 7912UC 7915UC 78L05 78L 12 LM324 555 $0.50 $0.50 $0.50 $0.60 $0.60 $0.60 $0.40 $0.40 $1.00 $0.40 $0.50 $0.45 $0.45 $0.45 $0.55 $0.55 $0.55 $0.30 $0.30 $0.90 $0.38 $0.45 10+ fan•, only $15.95 FANS Qualfty fans for UN In power amps, computer hotspot cooling otc. Anywhore you need plonty of air. 240V 4 S/8" T12461 .. $16.95 115V 4 SIB" T12463 .. $16.95 240V 3112" T12465 .. $16.95 115V 3112" T12467 .. $16.95 10+ fan ■ (rTixed) Only $14.95. TOGGLE SWITCHES $8.95 HEATSINK COMPOUND Heatalnk compound la applied lo the base and mounting atuds of translators & diodes. It maintaina a positive heataink seal that Improve• heat tranafer from the device to the heataink, thua increasing overall efficiency. H 11800 .. 10g ... $2.00 H11810.150g. $29.95 BC549 ...........$0.15 9C550 ........... $0.30 1410 ........ $1 .95 141 E.... .....$1 .95 142E or Teccor OOBL Trlac.$2.25 1460 ........ $2.85 1510 ........ $2.95 038 or CR 100·6 .....$0.90 1060 Equiv. Tag 403DE ...... $1 .50 220 .......... $2.50 122E ... ....... sa 5 646 ......... $1.95 ... .... $1 .20 Descri ption ....$ 2N918 .. .... $1 .00 2N2219 .. . ... $0.90 2N2369 ... .... $1.00 2N2646 ........ $1 .95 2N2904 ........ $1.10 2N3019 ....... SUO 2N3055 ........ $2.00 2N3563 ........ $0.35 2N3564 ... $0.30 2N3566 ........ $0.30 2N3569 ........ $0.30 2N3638 ........ $0.30 2N3641 ........ $0.30 2N3642 ........ $0.30 2N3643 ....... . $0.30 2N3644 . .... $0.30 2N3645 ........ $0.30 2N3771 ........ $6.96 2N3772 ........ $S.70 2N3773 ...... . $7.9S 2N3819 ........ $1 .50 2N3866 ........ $2 .95 2N3904 ····•·· · S 1.00 2N3906 .... $1 .00 2N4033 .. .... $2.20 2N42S8 ..... $0.40 2N43S6 ........ $0.50 2N4360 .. ...... $1 .50 2N4342 .. ...... $1 .50 2N4401 . ...... $0.30 2N4427 ........ $3 .90 2N5484 .. ... .. . $1.S0 2N5088 ........ $1.00 2N6089 .. .. .... $1 .00 2N5401 ........ $0.3S 2N5458 ........ $0.90 2NS4S9 ....... . $1.00 2N5485 ... ..... S1.1 5 2N5486 .. ...... $1 .30 2N6027 .. ...... $1 .20 2N612S ........ $1 .90 2S03S0 .. ...... $6.9S 2SJ49 .......... $9.95 2SJS6 ....... $14.50 2SK134 ........ $9.95 2SK176 ... .... $14 .S0 ■=M•Wtl UA.Me KBPC607 ,ooov............ s2 .75 J.Q..AMf KBPC1004 400V.............. $3.SO KBPC1007 1ooov............ 4 .so s ~ KBPC2504 400V..............$6.50 KBPC2510 ,ooov. .... $7.35 li.AMf KBPC3504 400V........... $6.50 KBPC3506 SOOY. ...... $6.7S KBPC3S10 1000V . .......... $8 .4 0 t!iPiW1f'lir1 AC128 ...... ... ..$2.95 BC107 ...........$0.80 BC108 ... $0.80 BC109 ........... $0.80 BC212 ........... $0.30 BC318 ........... $0.30 9C327 ........... $0.30 9C328 .... ....... $0 .30 9C337 ........... $0.40 BC338 ........... $0AO BC548 .... ..... .. $0 .30 9C547 ... ........ $0 .15 !!C548 ...... .....$0.15 9C5S6 ...........$0.30 BC557 ...........$0.15 RC558 ... ....... . $0.15 =~:::::: ::::::~:~ 9C640 ........... $0.80 B0139 ..... ...... $0 .90 B0140 ........... $0.90 90237 ........... $0.90 90238 ... ........ $0.90 90650 ........... 95 90649 .........$l. 65 B0647 .. ..$1.80 B0681 ........... $2.00 B0682.. ..$2.00 BF115 ... $l.OO 9F180 .$l.20 BF199 ... ........$0.SO BF245A ......... $1.95 BF469 ...........$1 .20 BF470 ...... .. ... $l .20 BFY50 ........... $1 .SO s,. BFY90 ....... .... $3 .00 BU208A ........ $4 .90 9U326A ... .... .$4 .95 eux00 .......... $5 .95 BUBO&.. ..$7.95 MFE131 .... .... $2.90 MFE3001 .. ... .$9.90 MJ10012 .. .....$5.95 MJ802 ·····•·· ···$7.80 MJ1S003 ....... $9.SO MJ1S004 ....... $9.70 MJ1S024 .......$9.60 MJ2955 ....•.... $2.95 MJ4S02 ......... $8.SO MJE340 .........$2 .00 MJE350 .........$2.SO MJE2955 ....... $4 .90 MJE3055 ....... $3 .90 MJE13007 .....$4 .95 MJE13009 .....$9 .95 MPF131 ... .... .$2 .00 MPSA06 ... ..... $1 .00 MPSA 13 ........$0.SO MPSA42 ........ $0.80 MPSA43 .. $0.SO MPSA93 ........ $0.SO MPF102 ........$0.90 MPF109 ........$0.90 MPSU56 ........ $1.75 PN100 ........... $0.25 PN200... . ··· $0. 2S TIP31 B .......... $1.00 TIP31C .. ..... ... $1.20 TIP329 .......... $1.00 TIP32C ..... .....$l .20 TIP41A ... ..... ..$1.90 TIP41C ....... ... $2.00 TIP42A ......... .$1 .90 TIP42C .. ........ $2.00 TIP49 ......... ... $1 .90 TIPSO ............ $2.20 TIP53 ............ $2.SO TIP112 ...... ... $2.SO TIP116 ........ ... $2.SO TIP117 ...... .... $2.50 TIP120 .... $2.90 TIP122 .......... $1. 9S TIP125 .......... $2.90 TIP127 .. ....... .$1.9S TIP147 .. ......$4.9S TIP29SS ........ $2.25 TIP30SS ... .....$1.9S l'll'l'ltP ..1.A.Mf. .Descrip tio n .. $ 1N4002 2oov .$0.10 1N4004 400V .$0.10 1N40071cmv .$0.20 lAl,lf Oescripl,on.. S 1N5401 SOV .. $0.40 1 NS404 400V $0.40 1 N54081 OO0V$0.65 GERMANIUM DIODE Description ... ... ..$ OA47 ... $1.SO OA90 ... ........ $0.40 OA91 . ........ $0. 7s OA95 ........... $0.76 lli'iffiJI 1 N746A 3V3 .$0.25 1N747A 3V6 .$0.25 1 N748A 3V9 .$0.25 1N749A 4V3 .$0.25 1N7S0A4V7 .$0.25 1N7S1A 5V1 .$0.25 1N752A 5V8 .$0.25 1 N753A 8V2 .$0.25 1 N754A eve .$0.215 1N755A 7V5 .$0.25 1 N755A 8V2 .$0.25 1N757A 9V1 .$0.215 1N758A 10V .$0.25 1N962A 1N759A 1N964A 1N965B 1N966B 1N967B 1N968B 1N969B 1N970B 1N971B 1N972B IN973B 1 N9749 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 74HC174 .......$1 .40 74HC244 .•..•.. $2.00 74HC245 ....... $2.SO 74HC273 .......$2. 75 74HC367 .... ... $1. 85 74HC373 .......• 1.80 74HC393 ....... $2.75 74HC4040 .. ...$1 .65 74HC4060 ..... $3.95 74HC4066 .. ... $1 .70 H1illt1\'l'I'! Description ........ $ so. 4000 .............. 75 4001 .- .... ........$0.46 4002 ............ .. $0.55 4006 ... ...... .. ... $1.55 1W ZENER DIODE 4007 ..... .. ... .. .$0 .45 Description ... ... ..$ 4008 ........$1.70 1N4728 3V3 .. $0.35 400Q .............. $0.00 1N4729 3V6 .. $0.35 4010 .. ... $0.90 1N4730 3V9 .. $0.35 4011 .... ..... $0. 48 1N4731 4V3 .. $0.35 4012 .............. $0.45 1N4732 4V7 .. $0.35 4013 ..............$0.70 1N4733 5V1 .. $0.35 4014 ............. $1.00 1N4734 SVG .. $0.35 4015 . ......... ...$0 .90 1N4735 6V2 .. $0.35 4018 ........ .....$0.70 1N4736 6V8 .. $0.35 4017 .... .s, .35 1N4737 7V5 ..$0.35 4018 ........ ..... $0.SO 1N4738 8V2 .. $0.35 4019 ... .... ...... $0.80 1N4739 9V1 .. $0 .35 4020 ..... $1.40 1N4740 10V ..$0.35 4021 .............$1.50 1N4741 11V .. $0.35 4022 .... ......... $1 .45 1N4742 12V .. $0.35 4023 ........ ... so.45 1N473313V ..$0.35 4024 ...... .... ... $1.60 1N474415V ..$0.3S 1N4745A 16V$0.35 . 4025 ... ···•··•· ·· So·45 4026 ... .. .... ... $1.10 1N474618V .. $0.35 4027 .......... ... $0. 85 1N4747 20V .. $0.35 4028 ..... ..... ...$1 .15 1N4748 22V .. $0.35 4029 ............. $1.50 1N4749 24V .. $0.35 4030 .. $0.50 1N47S0 27V .. $0.35 4033 ...... ..$2.75 1N47S1 30V ..$0.35 4038 ..... ....$2.2S 1N4752 33V ..$0.35 4040 ............. $1 .20 1N4753 36V ..$0.35 4042 ..............$1 .50 1N4781 75V ..$0.80 4043 ... ........... $1 .20 4044 .............. $1 .25 404S .............. $4.90 404o .............. $1 .00 5W ZENER 4047 .............. $1.90 4049 .............. $0.60 DIODE 4050 ...... ........ so.60 Description ...... ... $ 40S1. ..:..... $l .20 1NS339B 5V6$1 .50 40S2 ...... $1.20 1N5342B 6V8$1 .S0 40S3 .............. $l .20 1NS3499 12V$1.50 4060 ...... ..... ...$2.SO 1NS3SB 1SV$1 .50 4066 .............. $0.80 1NS361 27V $1.50 4068 ........... ...so.so 1N63S9 24V $1 .50 4069 .............. so .so 1N5363 30V $1 .50 4070 ......... .....$0.SO 1N5372 62V $1 .50 4071 ... ...........$0.SO 4073 ......... .....$0.SO ■tf;fi-i('1f1' 4075 .............. $0.SO Description ... .... $ 4076 .............. s, .QO 1MHz ............$6.00 4077 .............. $0.50 1.8432MHz .... $7.50 2MHz ............ $3 .00 • 4076 .............. $0.SO 4081 .............. $0.SO 2.4576 MHz ... $2.00 4082 . . ... $0.SO 3MHz ............. $4 .90 4093 .......... ... $0.80 3.57954MHZ .. $3.00 4098 ............. $1 .90 4.00 MHz ....... $3.00 4S104 .. . ...$7.25 4.19430MHZ .. $3.00 4503 .. ........... 30 4.433618MHz$2.00 4510 .... ..... ... 40 4.44 MHz ....... $2.00 4511 . ....... .. ... $1.4S 4.9S62 MHz ... $3 .00 4S12 ............. $1 .40 SMHz ............ $2 .00 4S14 .............$2.60 6 MHz ........... $2 .00 451S .............$l .90 6.144 MHz ... .$3 .00 4S16 .. .$l .60 8.00 MHz ....... $3.00 4518 ... .$1 .50 8.86723MHZ .. $3.00 4520 .... $1.00 10 MHz .......... $2.00 4S22 ...... ······S'-OO 11 MHz .......... $3.00 4526 ............. $1.00 12.00 MHz ..... $3.00 4S28 ..... ........ $1 .95 14.318 MHz ... $2.00 4532 ... ......$2.65 15 MHz .......... $2 .00 4536 . ···• •· ..... $6.50 16.00 MHz .... .$3.00 4S38 ............. $1 .20 20.00 MHz... .. $2.00 4543 .... $2.SO 24 MHz... ....... $3.00 45S6 ............. $1 .2S 48MHz ........... $2.00 4S84 ..........$1.00 32.768KHz .... $2.00 40014 ........ ...$1 .50 40175 . ....$2.00 l'IMN 1:i,;111 s,. s,. ■r<at>INUI Description ... ...... •· .$ 74HCOO ........ $0.7S 74HC02 ..... .. .. $0.75 74HC04 .... .... $0.7S 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 .. ... .. ..$1AO 74HC86 .......... 74HC123 ... .... $1AO 74HC132 .......• 1.25 ,.,o 74HC138 .......• 1AO 74HC1S7 .......$1 .25 74HC181 .......$2.25 74HC154 ....... $2.25 141<at>1 Description ...... . $ 74COO . ......... $1.00 74C04 .......... $1.00 74C08 ........... $1 .00 74C14 ..........$1 .75 74C74 ........ ...$1.00 74C86 ..... ..... $l .50 74C90 .......... $2.SO 74C192 ........$3.50 74C221 .........$3.95 74C244 . ···•···$3.95 74C373 . ·······$8.95 74C908 ..... $2.QO 74C922 ... ... $14.1111 74C926 ....... $13.1111 74C948 ...... $24.50 Mrtidil't1 7~~s;;~~l-~-~.:~s1:~ 74S08............$1 .SO 74S30........... .$1 .00 74S32............$1.00 74S132 .......... $3.SO 74S133 .......... $1 .20 74S138 ..........$2.50 74S139 .... ...... $3.30 74S174 .......... $3.50 P.ltwlltJ 74F00 ............$0.25 741'04 ... ...... ... $0.2S 74F32 ......... .. .$0.25 74F74 ............$0.25 74F109 .......... $0.SO 74F138 ..........$1 .00 74F151 ..........$1.20 74F153 .......... $1 .20 74F157 .......... $1 .20 74F194 .... ......• 2.4 1 74F244 .......... $3.·r; M1ttWl\i1 Description .... ... $ 74LSOO .........$0.30 74LS01 .........$0.60 74LS02 ...... ...$0.60 74LS03 ........ $0.60 74LS04 ......... $0.7S 74LS05 ... ...... $0.75 74LS08 ......... $0.60 74LS10 ......... $0.30 74LS11 ..........$0.75 74LS13 ......... $0.90 74 LS14 ... ......$0.7S 74LS1S ......... $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 74LS7S .........$1 .20 74LS76 ......... $1.00 74LS8S ......... $0.85 74LS86 .........$0.60 74LS90 ... ... ...$1 .20 74LS92 ... .. ... $1 .20 74LS93 ......... $1 .50 74LS95 .........$1 .20 74LS107 .......$0.90 74LS109 ....... $0.QO 74 Ls112 ........so.10 74LS123 ....... $1 .30 74LS125 ....... $1 .00 74LS126 ....... $1 .00 74LS132 ....... $1 .00 74LS138 .... ...$0.80 74LS139 .......$0.80 74LS14S ....... $1 .50 74LS147 .......$2.50 74LS1S1 ....... $1.20 74LS1S3 .... ... $1.00 74LS 155 .......$0.SO 74LS156 ... $1 .50 74LS157 ..$1 .20 74LS158 .. $1.00 74LS160 .......$1 .50 74LS161 ....... $1.00 74LS162 ........ $0.5-0 74LS163 ....... $1 .10 74LS164 .......$1.40 74LS165 ....... $1 .20 74LS168 ....... $1.25 74LS168 ....... $2.10 74LS174 ....... $1 .20 74LS175 ....... $0.70 74LS181 ....... $4 .00 74LS191 ....... $1.20 74LS193 .......$1.20 74LS19S ....... $0.50 74LS1116 .......$1.20 74LS221 ...... .$2 .00 74LS240 .......$1 .40 74LS241 ..... ..$0.9S 74LS243 .$1 . 10 74LS244 ....... $2.20 74LS245 ....... $2.95 74LS257 .. .... $1 .20 74LS258 ...... $1 .20 74LS259 .. .... $2.25 74LS268 ....... $0.70 74LS273 .... ... $1 .00 74LS323 ....... $6.50 74LS352 ....... $2.20 74LS366 .... .. . $1 .00 74LS388 ....... . 1.00 74LS387 .. . $1.00 74LS373 .... ... $2.00 74LS374 .... ... $2.00 74LS375 ....... $1.00 74LS393 .......$1.00 74LS629 ....... $5.95 74LS640 .......$1.00 Ntidil!tl Oescripton ........ $ 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 ·············'o.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 ..... ..... ....$0AO 7475 .............. $1 .20 7476 .............. $1 .50 7483 .. ............ $1 .10 7490 .............. $1 .20 7493 ..... ......... $1 .25 74121 ······ · ... .$1 .55 74123 ... ........ .$0.50 7412S ............ $1 .00 74126 ... ... ..$1.00 74150 ............ $1.90 74154 ... ........ $2.50 74157 ............ $1 .30 74161 ........ .... $1 .20 74164 ............ $1 .20 74177 ..• 1.95 74193 ............ $1 .50 7419S ............ $1 .00 . 74197 $1.20 74283 ............ $2 .45 74290 ............ $0.90 P\tl'Kl·TI•f Descri ptio n ........... $ DAC0800 .......$4 .9S DAC0808 ........$4.90 AOC0800CN .$29.9S ADC0803 ..... $13.S0 ADC0804 .... ... .. $7.95 ADC0808 ....... $13.00 ADC0820LCN .$27.95 DAC0832 ......... $7.9S DAC1020 ....... $16.28 11c90 ............ ,,s.so OAC1220 ....... $22.95 DAC1408 ......... $1 .00 .AD590J ...... ... $12.95 l\1!Wt-Jil . Oescnptl on ....... $ AY·3·1015 ..... $11 .95 . :AY·3·8910 ..... $19.95 .AY·5•8116..... $14.50 CA3028 .......... $3.95 CA3086 .......... $1 .20 CA3130E ........ $2.90 CA3130T..... .... $3.9S CA3140E ... ...... $1.30 CA3140T......... $2.95 CTS256A ..... . $45.60 . DM2502 ........ $13.50 LF347 ............. • ,.40 LF351 N........... $1 .20 LF353 ............. $l .GO LF3S6N ........... $l .50 LF3S7 ............. $2 .05 LF398 ........... · $5.9o LM301H ...... .. $1 .50 LM301N .... so .50 LM302H ........ · $6.SO LM305H .. . $1 .S0 . LM307CN ....... $1.50 LM308 ...... ... $0.50 LM309K $2.85 LM310N .... $4 .9S . LM311 .......... $1.00. LM324 ..... $1 .20 LM331 . . .....$6.00 . LM339 ... $0 .60 . LM348 ...... $1.00 LM349 ..... $2.95 LM358 ............. S1 .40 LM361 ............. $4.95 LM380N•14 ..... $1 .95 LM380N•8 ... .... $1.50 LM381 .............$4.95 LM382 ............. $3.50 LM383 ............. $4 .95 LM384 ............. $3.50 LM388•1 ..........• 1.40 LM387.. . . .. $2.75 LM390 ... ......... $2 .95 LM392 ............. $1 .SO .LM393............ .$0.60 LM394CH ....... $7.95 :LM395T...........$9.95 LM39SK .......... $7.95 LM396K ........ $16.50 LM399H .......... $7.50 LM711 ............ .$1.20 LM725 ............ $7.50 LM733......... ... $1.50 LM741 ............ $0.60 LM747............ $1.50 LM748............ $1.lO LM7S9............ .$3.90 LM833 ........... $2.10 LM1830 ... ...... $4.9 o LM1871N ........ $7.50 LM 1872N ........ SB.GO LM1886 ........... $9.10 LM2907·14 ..... $3.50 LM2907·8 ....... $5.10 LM2917•14 ..... $2.50 LM2917•8 ....... $4.80 LM3900 .......... $0.80. LM3909 ......... .$2.50 LM3911 .......... $3.95 LM3914 ......... $2.90 .LM391S ........... $2.90 .LM3999Z .. ..... $5 .95 .LM 4250 ... ...... .$2 .45 .LM11CN ......... .S4.95 LM13600 ... $2.70 LMC5S5 . . $1 .25 MAX232/ICC232 HMC232 ........$11.9S OM350 .... ...... $21.00 MC1408L8 ...... $7.50 MC1458 ... ....... $1 .20 MC1488 ...... .... $0.60 MC1489 ... ...... . $0.60 MC1496 .......... $2.50 MC3334P.. ...... $6 .95 MC3401aP... ... $8 .95 MOC3021 ........ $1 .95 NE555 .. ........... $0.50 NE556 ............ $0.95 089criptio n .......... $ 2114 ................ $5.20 2716 ... ........... $12.SO .. 2732.200 ........ $8.25 2764· 250........ $8.Q5 27128 .............. $8.00 27256·250 ...... .$9.SO 27512·250 .....$14.9S 27-lMEG .......$29.50 .... . 27C64·200NS . $8.95 27C128 ......... $12.SO 6 ~;~; ' .... .... $1S.so 27CS12 ........ $22.SO 27C 1 MEO .... $34.SO 4116 16K ........ $3.9S 4164· 1D ......... . $4.95 4464-10 ...... ... . SS.SO 4464•08 ........... $5.90 412S6·10 ....... .. $4.95 412S6·08 ......... $S.50 44256·10....... $13.95 442S6·08 ....... $14.95 44256·07 ....... $15.96 6116 ............. $5.SO 5264LP·10 .. $19.95 62256LP·10 .. $39.95 1M•10 ...... ...... $13.95 1M•08........... $14.95 - • Description .. ... ... $ 2S6 X 9·80 . ... $49.00 1M x 9-80 ... $125.00 1M x 9·70 ... $129.00 Desc ription .. ....... $ 2S6K x ~80 ..$49.00 1M x 9-80 .... $125.00 1M x 9•70 .... $129.00 81LS95 .......... .$1 .00 81LS96 ........... $2.75 8216 ... ........... s3 .oo 8237 .. $14.50 8255 ................$6.90 8279 .............. $8.50 8830 .............. $6.95 9SH90 ......... ..$10.50 9667 ..... ...... ... $0.90 9668 ·············· $2.95 WON •~i!if•l I ■ IHI ■ Description ....... $ 76489... .... $12.50 ICL7660.......... $6.90 VN88AF...........$S.115 MM5369 .......... $4 .QS $ escnplion ....... .. . 6502A .. ......... s·,s.96 6522A .. ... ...... $1S.9S 6802 .............. $7.: 6809 .............. $17. 6821 ················ $5.SO 6845················ $9·95 6850 ··· ············· $3.SO 7910 ............ $29.: 803SN·6 .......... $6.00 8039 ................ $9.00 8080 ................ $8. 808SA . ........ $16.: 8088............. $12. ICL7106 ........ $15.95 ICM72168 ..... $S9.50 LF13741 .... ..... $0.80 NS15450 ... .. $26.95 S3530 .......... $24.95 SP0256 •...... $21 .95 TR1863 ........... $8.90 V20A ........... $35.95 V20.............. $29.: WD2123 ........ $29.SO XR8038 ........... $7.SO Z80A CTC .. .... $8. z909 CPU .... $13.50 Z80A CPU .... ... $5.75 Z80A PI0 ........ $4.50 A 510 $14 50 Z80 ..... . - Description......... $ LM317T. .......... $2.SO LM317KC ........$5.50 LM320K12 ...... $1 .40 LM320K· 05..... $3.00 LM320T•5 ....... $1 .40 LM323K ......... $9.50 LM326 ............ $S.50 LM329DZ ....... $0.90 LM334Z .......... $l .70 LM335Z .......... $2.SO LM336Z·2.SV .. $2.95 LM336ZS.OV... $2.9S LM337T. ......... $2.90 LM337KC ..... $12.SO LM33BK ......... $9.4S LM34 0T•5 .. $0.90 LM340KC·5 ..... $2.9S LM340T·5 ...... $0.90 LM340KC•5 .... $2.9S LM340T·12 ..... $0.90 LM340T•18 .... $2 .00 LM340T·15 ..... $0 .90 LM340KC·12 .. $4 .95 LM3S0T....... ... $8.40 LM350K ........ $11 .SO LM378 ........... .$6 .95 T\_494 ..... ....... $4.90 LM723CH ...... $1.50 LM723CN ... $0.95 78HGK ............ $9.SO 78P05GC ... .. $14.50 7805 ................ $0.75 78L 12 .............. S0. 75 7BL 15 ........... ... $0.7S 79L05............. $1 .20 79L 12 .............. $1 .20 79L 15 ....... $1 .20 LM396IC . .....$16.50 IW0ii~I NE558 ............. $6.SO .NE564 ............. $7 .00 NES66.............$2.90 NE567 ............ . 2.00 NE570 ......$8.95 NE571 ..... $6 ·95 NES72 ........... $11.20 INS82SON .... $18.10 :rA720SP......... $2.9S TDA1024 ........ $3.90 TEA1002 .. ..... $17 .50 TLOQ'I ....... ...... $2.10 TL0711 LF3S1 . $1.20 TL072/ LF353 . $1.60 TL074/ LF347 . $1 .40 TL081 .............. $1 .90 T-l.082 ............. $2.20 TL084 ............. $1 .50 . UA710CN ....... $1 .00 .UA739......... ... .$2 .75 .UPD8288 .... $18.50 XR2206 ........... $9.95 XR2209 ........... $6.90 XR2211 ........... $7.95 XR2216 ........... $5.90 XR2240 ........... $6.95 XA2243 .... $5.95 26LS30 .......... $2.00. 26LS31 ........... $2.00 26LS32 ..... ..... $2.00 5534AN ......... .. $3.95 81S5 ................ $8.95 0 8 156................ $8 .5 ■ 1m;u,;4;.: Description .... ...... $ 3mm LEDS Rod ................. $0.20 Green ............. S;0 .30 Yollow ....... ...... $0.30 0,ango ........... $0.30 5mm LEDS Rod ................. $0.20 Green ............. $0.30 Yallow............. $0.30 . Orange .......... $0.30 10mm JUMBO LEADS Rod ................. $1.50 Green ............. $1.50 Orange ........... $1.50 SUPER BRIGHT LEOS Rod ................. $1.00 Green ............. $1.00 Yellow ............ $1.00 &nm FLASHING LEDS Rod ............. ... . $1 .25 RECTANGLE LEDS Rod ................ . $0 .2l5 GrHn ............ $0.30 Yellow ............ $0.30 Orange ........... $0.30 · 0: 8087·3 ....... $189.00 8087·2 ....... $279.00 8087-1 ....... $379.00 80287•6 ..... $249.00 80287·8 ..... $379.00 80287·10 ... $459.00 80387•16 .... $61111.50 80387·20.....$795.00 80387· 25... $81111 .00 80387•39 .... .$995.00 5mm RED/GREEN DUAL LED ..... $1.05 I r-Prices-are;:9.-7 I : I : : 10-99 less 10%. 100+ less 20%. : lI I l 1..----------.J The Story of Electrical Energy, Pt.14 This month, we look into the methods that make electrical energy use more efficient. For optimum voltage regulation and lowest running costs, the current and voltage need to he in phase or close to it. If they are not in phase, the energy losses are higher than they should he. By BRYAN MAHER Inductive electric machines and appliances draw lagging out-of-phase currents . Naturally, we would like the power station alternators to operate with minimum electrical losses and best power efficiency. And the same may be said for the high voltage transmission lines and transformers. To this end, the loads supplied should ideally draw a current in phase with the voltage. Why should that follow? Just read on. In most industries, AC squirrel cage induction motors form a major percentage of the load. Induction motors produce mechanical rotation by the interaction of the stator's rotating magnetic field with the conductors of the rotor. Being highly inductive , such motors draw currents which rise later than the voltage in each cycle. This is illustrated in Fig.1. In this diagram, the current is lagging the voltage by some phase angle <j>; ie, the current peaks come after the voltage peaks and so on. Resistive loads such as heaters, ovens, filament lamps and electrolytic baths (used for plating, etching, etc) draw a current which is exactly in phase with the voltage as shown in Fig.2(a). In other words, the current and voltage rise and fall together throughout each cycle. (The word "phase" originally meant "a division of time".) Inductive loads lag. Because the back voltage (or back-EMF) generated by an inductance opposes the applied voltage, a pure inductor takes a cur- SUPPLY VOLTAGE - . ._ ✓ MOTOR CURRENT '' ' TIME AND ANGLE i LAG ANGLE ONE CYCLE =360- =20 MILLISECONDS (50Hz) Fig.I: this diagram illustrates the fundamental nature of an induction motor load; its current waveform lags the voltage waveform. This causes problems because the distribution system must supply additional current. SILICON CI-IIP 0 Power & power factor The power as_sociated with a current is equal to the product of voltage, current and the cosine of the phase angle. This is expressed by the following formula: P = V.I.cos<j> The cos<j> term is also called the power factor (PF). Readers who remember their trigonometry may recall that the cosine of zero degrees is unity and that cos goo = o. Since there is zero phase angle between the voltage and current through resistive loads, their power factor is unity (because cos O = 1). This means that the power dissipated in a resistive load is simply the product of the voltage multiplied by the current. By contrast, all purely reactive (inductive or capacitive) loads do not use any power at all! This is because the cosine of their go phase angle (lag or lead) is zero and therefore they have zero power factor. 0 <I> 86 rent which is delayed by go with respect to the voltage, as shown in Fig.2(b). By contrast, capacitive loads lead. Because capacitive current is proportional to the rate-of-change of voltage, a pure capacitor draws a current which is exactly goo ahead of the voltage. Fig.2(c) shows that capacitor current is greatest where the voltage is changing at maximum rate; ie, at the zerocrossing crossing points on the voltage curve. Real machines In the real world, all inductive components have some resistance in addition to their inductance. Thus, iron cored coils have a power factor greater than zero but less than unity. Motor windings show both simple ohmic resistance and also inductance. But there's more here than meets the eye. A motor's job in life is to convert electrical current into mechanical ro- - / CURRENT IN PHASE .,,. - '- / " CURRENT LAGGING '\ / / I '\ I 90' LAG ' ' j",_ 90' LEAD CURRENT LEADING Fig.2: this diagram shows the phase difference between the voltage and current for three types ofload: (a} for resistive loads, the voltage and current are in phase; (b} for pure inductive loads, the current lags the voltage by exactly 90°; and (c} for pure capacitive loads, the current leads the voltage by exactly 90°. tation of the shaft. The total induction motor current can be visualised as having five components: (1). An inductive component to provide the magnetic field. This component has 90° lag angle;, ie PF = 0. (2). The simple ohmic resistance of the copper windings. (3). The eddy current iron losses. (4). · The mechanical friction and windage losses . (5). The mechanical power output at the shaft. Note that the last four components all have a power factor of 1. The first four of the above components are reasonably constant. However, that fifth component of motor current clearly varies with any changes in mechanical load. Factory example Suppose a factory receives a 3-phase supply at 11kV. This company would provide its own 11kV/415V transformer for all its machines. Perhaps this installation contains 100 induction motors. Let's further suppose that the average motor current is 134.54A. If we made careful measurements, we might find the power or in-phase component to be 100A, while the magnetising or lagging out-of-phase current component is 90A. Assuming this motor to be typical of all 100 machines, the total factory current supplied by the transformer is 13,454 amps, which amounts to quite a sizeable installation. The vector diagram of Fig.3 shows how the current components relate. In this example, the 42° phase angle is typical for the whole factory, where some motors are on full load and some are lightly loaded. If a motor is on no load, the inductive component of current predominates, so the motor current would have a large lag angle (about 80°} and a low power factor (around 0.2). But on full load, the power component (number 5 in the list above) exceeds all others. Thus, the total motor current would have a small lag angle (around 30°). The full load power factor would be about 0.85. You might wonder what lag angle and power factor has got to do with the price of energy. In fact, the factory electricity bill is charged only on the in-phase or power component. The meter measures kilowatt-hours. The kilowatt is truly a measure of power and the kWh reading is the energy used at a certain power over some number of hours. None of these indicate anything of the reactive outof-phase current component, because its power factor equals zero. So why should the consumer worry? Why should the factory manager care? He should and does. For consumers like our industrial example, the outof-phase component of current is a very big part of the total amperes flowing into and through the factory's 11kV/415 transformer. We call the product of voltage and out-of-phase component of current by the name Volt Amps Reactive, or VAR. Naturally a thousand of these we call kVAR, (kiloVARs},oramillionMVAR, (megaVARs). As we have already seen, the main factory transformer must supply 415 V, 3-phase, at 13,454A. That's quite a big unit and its size is expressed by the product of voltage and line current. This product is (✓ 3 x 415V x 13,454A) = 9.6707 million volt amps. This would normally be expressed as 9.67MVA. Looking back, we see that MW is simply the product of MVA and PF. However, if built to provide almost 10MVA, that factory transformer is likely to be a lot more expensive than "--""'go""'oo""A""M""Ps'"'1""'Lo""u=-TO:::F""P""HA""SE:,---,-8 This is a vector diagram showing an induction motor load in which the phase angle bet\\!;een the load current and the applied voltage is 42 °. If a suitable bank of capacitors was connected in parallel, the phase angle between current and voltage could be reduced to zero and the resulting current drawn from the distribution system also reduced. OCT0BER1991 87 would have to flow in the transformer's 1 lkV primary, in the state grid system and all the way back to the alternator stator windings in the power station. Without power factor correction somewhere in the system, all power line conductors, circuit breakers, transformers and metering equipment would have to be of higher current capacity, just to supply that outof-phase current component for which the customer would otherwise pay no extra. Therefore, most supply authorities apply penalty charges to the electricity bill to cover the cost of the additional plant they must provide to cover low power factor loads. Usually a "maximum demand" recording ammeter is installed and the price per kWh of power used is increased as a penalty for currents above a predetermined value. Control of capacitors You might wonder what happens if half the motors are switched off for some of the time? In this circumstance, This is a large outdoor bank of capacitors for power factor correction. There are three vertical banks, one for each phase of the mains supply. it needs to be. Observe that only the 10,000A in-phase component of the current produces any power. The other component, the 9000A magnetising current (although vitally necessary to form the magnetic fields) produces no power. Neither does it consume any power from the supply. Wouldn't it be nice if the transformer only had to supply the 10,000A in-phase component of current? This can be done by adding capacitors to the circuit. Capacitors Recall that capacitors take a leading current; ie, a perfect capacitor takes a current which leads the voltage by 90°. Fig.2(c) illustrates this. Ifwe add enough capacitors to the secondary windings of the transformer, we can 88 SILICON CHIP cancel out the lagging current of the motors. Because it is a 3-phase system, we will require three identical capacitor banks. The photos show some typical installations. So by adding suitable capacitors to the installation, we have reduced the transformer secondary current from 13,454 amps down to 10,000 amps. This enables a transformer rated at around 7MVA to be used instead of one rated at lOMVA. That's a big reduction in size and cost! Running costs are also reduced. Smaller transformer currents mean smaller losses and therefore less continual costs. Penalty charges There are other benefits too. Without capacitors installed, extra current Banks of power factor correction capacitors can be very large or relatively modest as with these units made at Asea Brown Boveri's Capacitor Division at Lilydale in Victoria. You can now afford a sate II ite TV system For many years you have probably looked at satellite TV systems and thought "one day". You can now purchase the following K band system for only $995. 00 This is about 1/3 the price of corn parable systems Here's what you get: _. A 1.8 metre pressed steel prime focus dish antenna, complete with all the mounting hardware - as well as a self supporting ground stand. The induction motor is the cause of most power factor problems in the AC power distribution network, along with fluorescent lamps. Because it is an inductive load, the motor current lags the AC voltage waveform and that means extra current has to be provided. the remaining motors only take about 4500A of out-of-phase lagging current but the capacitor bank would still be taking its full 9000A of leading current! This would amount to having over-compensation and so the total factory current would be higher tha.n necessary, with a leading power factor! There are three ways to prevent such a situation: (1) Rather than have one large bank of capacitors for the whole factory, we could use separate capacitors for each motor. This way, when the motor is switched off, so too is the capacitor. This method can have a severe disadvantage, though. Each time the motor circuit breaker is opened, if the capacitor and motor inductance find resonance at the wavefront frequency, a large overvoltage spike may be generated. In extreme cases, this has been known to puncture the motor winding insulation. When next the motor is switched on, explosive breakdown can occur. (2) Alternatively, the large bank of capacitors may be divided into sections, each brought on line as required according to the number of motors in use. Computers are now used to monitor the power factor and control the switching of capacitor banks. (3) Finally, another method of power factor correction involves using a unloaded synchronous motor. However, that m ethod is beyond the scope of this article. Fluorescent lights It is not only induction motors that produce lagging power factor problems. Fluorescent lamps also have a lagging power factor, because of the current limiting inductor (known as a ballast). This typically results in a power factor of between 0. 7 and 0.8. When you consider the thousands of fluorescent lamp fittings used in all commercial buildings, factories and public buildings such as schools and hospitals, the leading power factor becomes a major problem for the supply authorities. For this reason, in commercial and public buildings, the supply authority requires that each fluorescent lamp fitting contain a power factor correction capacitor. This is connected in parallel with the 240VAC input. Power correction capacitors are not required for fluorescent lamps used in homes, however. Acknowledgements Grateful thanks to the NSW Electricity Commission and to ASEABrown Boveri for data and photos and permission to publish. SC _. One super low noise LNB (low noise block converter) 1.4dB or better. _. 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. 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. CALL, FAX or WRITE to AV-COMM PTY LTD. PO BOX 386, NORTHBRIDGE NSW 20.63 PHONE (02) 949 7417 FAX (02) 949 7095 All items are available seperately. Ask about our low noise 'C' band LNB, and other interesting products. All systems are provided with dish pointing details. ----------- 1 Yes Garry, Please send me more information I on your K band satellite systems. II Name ....................................... I Address ............... .................... I ................................................... II ...........................P/Code .. ....... . I Telephone .. ... .. .. .. ... ... . .. .. .. .. ..... I I II I I II I .~N=~!:.------0=· OCT0BER1991 89 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. Problem with the frequency meter I recently constructed a 1GHz Digital Frequency Meter kit as published in the November 198 7, December 198 7 and January 1988 issues of SILICON CHIP. All of the tests and precautions as outlined in these articles were carried out successfully except the use of the red 1.7 volt LED for sensitivity adjustment. I have experienced sim\lar difficulties and symptoms as explained by a fellow reader, G. W. Willmot, NSW, in December 1988. All of your previous suggestions to solve this problem have been strictly followed, without success. As an alternative to the LED method, I adjusted the lkQ pot until the resistance between pins 9 & 11 of IC2b was equal to the resistance between pins 10 & 11. The meter is now working. However, as I do not have any means of testing for sensitivity, I am con- Questions on diesel sound simulator I have a couple of questions about the Diesel Sound Simulator featured in the December 1988 issue of SILICON CHIP. I wish to install the simulator in a 5-inch gauge model that is powered by 12V car batteries. I am a mechanical engineer and my knowledge of electronics is very limited. As I will not be running with a long lead connected to mains power, I propose by-passing the transformer and rectifier and feeding the circuit with straight battery power. Will this work? Will I need the 7812 regulator part of the circuit? At the end of the day, I expect battery power to be low and consequently the sound system to not work well or at all, but if I can live 90 SILICON CHIP cerned that my alternative method may not be as accurate as the original design method. With reference to the above could you please advise: (1) is my alternative method correct?; and (2) if not, does your design team have any additional suggestions to rectify the problems with the sensitivity adjustment? In addition, I am also experiencing difficulty in obtaining reliable readings when using the meter on RF circuits, particularly at VHF and UHF levels. My present probe is only a length of 50Q coax terminated into two short roving leads with alligator clips fitted. It would therefore be appreciated if your designers could provide me with construction details of suitable probes for both the 1MQ and 50Q inputs. (K. F., Lawnton, Qld). • Your method of adjusting the sensitivity is not correct. This is because the upper and lower thresholds of the 10116 are not proportional to the bias levels. with this, will low power have any deleterious effect on the circuit? Can I simply leave out the location sensor part of the circuit, as I will be carrying speakers on board? Can I drive extra speakers in separate models from the one simulator, with an amplifier for each speaker, and have the volume controlled by my throttle? Do you know if this project has been "kitted" by any local firms? (I. K., West Wollongong, NSW). • Your proposed changes to the circuit will work although you should leave the 7812 regulator in place. The circuit will not be damaged by low supply voltages although it is possible that it may oscillate if the voltage becomes very low. This project did not become available as a kit although all the parts are readily available. Since the LED does not appear to turn on and off, we suspect that the ECL device is not working properly and has insufficient gain. Check that all the resistors around the 10116 are correctly soldered into circuit, particularly the 100Q feedback and input resistors. We emphasise that the LED must turn on and off for the sensitivity adjustment to be working properly. Once you have the sensitivity adjustment working correctly, you will probably find that you will have less problems in obtaining reliable readings when using the meter on your RF circuits. We have not found it necessary to go to the trouble of designing special probes. Using a clock radio to turn on a light I have had an idea in my head for a few years but haven't done anything about it. Every year as the days get shorter I think of it again: to use the common old clock/radio/alarm to turn on a 240VAC light as well as the radio in the morning. Somehow, a simple low voltage circuit would drive an SCR with a socket attached to the rear of the radio to run the light. How does the alarm unit turn on the radio - they would all be the same surely? (L. T., Lake Cargelligo, NSW). • While the idea to use a clock radio to turn on a 240VAC lamp is a good one, we are not keen on readers doing it since the wiring inside clock radios is not easy to follow and there are major differences between brands. On the other hand, if you are confident in following the wiring of a clock radio, it shou1d be relatively straightforward to pick up the DC supply to the radio (at the multi-position switch) and use it to supply a 12V relay or an optocoupled Triac circuit. We must advise caution though, because the mains isolation of the transformers inside these radios may be suspect. Remember that it was not designed for external circuitry and it may possibly present a safety problem. Note that some clock radios now available do incorporate a light - it may be easier, cheaper and safer to buy one of these rather than modify an old model. Tachometer needs different meter Congratulations on a really good publication; long may it continue. I have a problem with an old automotive tachometer. The meter is OK but the circuitry's shot. The problem is that most projects which utilise 555 timers or 2917 frnquency-voltage converters are only good for meters of lmA FSD. This particular meter has an FSD of lOOmA. Could you possibly help out with a circuit that will be suitable? Also any chance of a car trip computer in your list of future projects? Thanking you for your help. (A. M., Kingsley, WA). • Adapting a lOOmA meter movement to a tachometer circuit which specifies a lmA meter is a straightforward process. Normally, all you need do is shunt the meter so that a total of lmA flows for "full scale deflection". Try shunting the meter with a resistor of 1 lOQ and you should be pretty close. The normal circuit calibration should then give correct operation. To mute or not mute the Speakerphone I am building my second version of the Speakerphone, as described in the September 1988 issue of SILICON CHIP and I want to leave out the microphone muting switch, so as to keep the wiring as simple as possible. Is there any reason why I should not leave it out? (S. W., Hurstville, NSW). • Yes you can leave it but it is a very good convenience feature. It is handy to be able to mute the microphone when someone in your household wishes to speak privately to you. Or more importantly, you can use it when you want to sneeze or cough. When you feel one of those monster sneezes coming on, you just hit the Mute switch, let the sneeze rip and then hit the Mute switch back again, without the person at the other end knowing that you've momentarily just about "carked it". Note: "cark" Hum problem with hifi gear I have a small problem which I hope you will be able to help me with. I have a small hifi unit, Philips FT 9400 with CD player AK 601, which is rated at 20 watts per channel into 8-ohm loudspeakers. In addition, I have a pair of old Quad Electrostatic speakers which require more drive than that provided by the Philips unit. To overcome this problem, I constructed the Studio 200 stereo amplifier which works very well indeed with the Quad speakers. I wish to use the output from the Philips amplifier as the input to the Studio 200. This I have tried but find the background hum objectionable. Coupling the CD player directly to the Studio 200 overcomes the hum problem but, of course, the controls are bypassed. Not being an expert on electronics, I am guessing that it has some- is a colloquial (intransitive) verb, shortened from carcass, as in become a carcass! How to broadcast a simulated stereo signal I would like to get hold of some data cards showing the characteristics of stereo FM radio ICs and the BA1404 stereo FM transmitter IC. I wish to know how they work and want a few test circuits, as well as a circuit to build if possible. What I wish to do is use the MPX and pilot output of the BA1404 and connect it directly via a lOpF ceramic capacitor into the modulation input on a stereo radio so as to achieve what radio stations do. I went to Triple-T FM in Tasmania and they had a stereo generation unit which turns the audio signal into a stereo signal ready to go into an RF amplifier. The whole purpose of this is to change a mono signal into stereo by feeding the mono signal into a stereo simulator, then through a filter network, a 741 comparator circuit, then finally turn it into true stereo. thing to do with mismatching but how to overcome this is my problem. I should welcome any advice you are prepared to give. (H. F., Cloverdale, WA). • An earth loop is the most likely reason for you hum problem. This is because the CD player, original hifi amplifier and the Studio 200 amplifier are probably all earthed back to the mains. To cure the problem, you need to make sure there is no earth connection between the signal circuitry of your Philips amplifier and the earth of its mains cord. This may be difficult to do without prejudicing the safety of the unit. It is also possible that the hum may be present in the output of the Philips amplifier but is normally not produced because of the limited bass response. In this case, also, there is no easy solution. Have you considered building the Studio 200 preamplifier which was published in the June and July 1988 issues of SILICON CHIP? This would certainly solve your problems. All of this will be in three separate shielded cases, one being for the simulator, filter network and bass treble boost; the second for the BA1404; and the third for the radio. Hopefully the radio will not get outside interference so the shielded cases should have only two shielded plugs for input, two for output and shielded sheath for the bass, treble and volume. I think it will be possible to feed any mono signal in and achieve the result of a radio tuned in to a stereo transmission. (J.E., Blackburn South, Vic). • Unfortunately, we cannot assist you with data for stereo FM radio chips or any other devices for that matter. While we do have a comprehensive library of data which is being added to all the time, we do not have general permission to provide this data to anyone who asks. We have to seek permission for any data that is published in the magazine. Your best source for this information would be the Philips Electronic Components division in your state. Similarly, full data on the Rohm BA1404 chip would be available only OCT0BER1991 91 New light on amplifier suppression In the "Ask Silicon Chip" pages of the April 1991 issue, I wrote about a larger suppression capacitor quieting the turn off thump of an amplifier - to which you noted that there was possibly voltage still present at the rails. I no longer have the amplifier concerned so I cannot actually say yay or nay. However, given that I know that the power supply input circuit was as attached, I find it very difficult to envisage any voltage being present after turn off. Even if only a single pole switch were used, I doubt if any voltage would remain. (R. P., Belgrave Heights, Vic) -• Thanks for your follow-up let- from the distributor, Fairmont Marketing, in Preston, Victoria. Phone (03) 471 0166. However, we cannot see the point of using an FM stereo transmitter chip and a subsequent FM radio chip if all you want to do is to obtain simulated stereo from a mono signal. All you really want is a stereo simulator circuit. On the other hand, if you really do want to transmit the simulated stereo signal, the BA1404 transmitter circuit, as published in the October 1998 issue of SILICON CHIP, can be used and then received by any FM radio; there is no need to build an FM radio for the purpose. We have not published a circuit for a stereo simulator although a number have been published in the past in other magazines. At least one of these is still available from Dick Smith Electronics, Cat No K-342i. Mind you, no circuit can produce true stereo sound from a mono signal; it is just not possible. Adapter for computer monitors I am a little bamboozled by all the different computer monitors. There are mono and colour graphics adapters, enhanced graphics adapters and video graphics adapters. As far as I can gather, the outputs are not interchangeable, but I have 92 SILICON CHIP SUPPRESSION CAPACITOR A---0 240V \ ~-+-...I !El I TO AMPLIFIER N---0 jELECTROSTATIC 1. SHIELD E - • - - - - - -.. ~ ter regarding the suppression capacitor in your amplifier. Now that we see the circuit connection for this capacitor, we agree that your amplifier would have no power present when it is turned off. In many amplifiers though, only a SPST mains switch is used and the capacitor across the switch does allow some power to be applied to the mains transformer. often wondered whether a simple circuit could be devised for any of these units which could be fed to the video inputs at the back ofmy TV set. If this is possible, perhaps you could do a project along those lines? (D. S., Christchurch, NZ). • Our regular columnist Jennifer Bonnitcha has devoted several past articles to the differing video standards of computer monitors. Unfortunately, there is no way that any simple circuit could be made to make them compatible with each other or with a PAL TV set. The big problem is that , apart from CGA monitors, the sweep speeds of all computer monitors are faster, often many times faster than for a PAL TV set. Apart from that , the video bandwidth of a PAL set or even one that has a SCART socket for direct RGB connection, is far inferior to that required for computer monitors. Combined Discolight & 4-channel lighting desk? Whilst reading the June 1991 edition of SILICON CHIP, I saw the article on the new 4-Channel Dimmer. After reading this article, I thought that this had all the hallmarks of a great kit. However, I did feel that it lacked something of importance. Most DJs who operate discos like to be able to put some of the sound into visual effects. The Discolight (I own one, as described in July and August 1988) allows you to put sound, straight from the stereo, into light, via the Discolight box. But this kit also lacked a dimmer function. So where do I go now? I would like to have this 4Channel Dimmer but it lacks "sound to light". On the other hand, I've already got the Discolight but it lacks a "dimmer" function. Well, I got out the schematics for both the Discolight and the 4-Channel Dimmer, and found that the outputs were much the same in each case. So with not much expense, time or knowledge, one could easily incorporate the Discolight into the 4-Channel Dimmer. The changes that would be needed would be to take the outputs from IC5 (4017 in the 4-Channel Dimmer) and trade them with the outputs of IC8 (4019 in the Discolight). This could be done in a couple of ways. (1). A switch for each channel could be used and you could select between 4-Channel Dimmer and the Discolight functions (but this really would defeat the purpose). (2) . You could do as above, but use a DPDT switch and have it so that you can have either the 4-Channel Dimmer, the Discolight or both. (3). This option would be for those who would want a more permanent approach. Just solder connecting wires to pins 10, 11 , 12 & 13 ofIC8 (4019) in the Discolight and hook them up to pins 3, 2, 4 & 7 ofIC5 (4017) in the 4Channel Dimmer. So if you hooked theseupyou could have chaser, superimposed by flashing, which would be superimposed by chaser from the Discolight, all of which would chase in time with the music. Sounds great doesn't it? And there is no cost involved. On the top panel of the 4-Channel Dimmer box, where the slide pots are, all you need to do is drill seven holes - two for the pots and five for the select switches (one the Discolight). The Discolight could be run from the switch on the 4Channel Dimmer. (N. C. , Mundaring, WA). • We are not keen about incorporating Discolight circuitry into the 4Channel Lighting Desk. Perhaps you did not see the October 1990 article on adding dimmer controls to the Discolight? We suggest that this is a better solution. SC --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 $Al.GO per issue for postage. ISSUE YEAR YEAR ISSUE ISSUE YEAR ISSUE YEAR TOTAL$A SUBSC RIPTIONS: RATES □ NEW SUBSCRIPTION: Month.To Start □ RENE WAL:SubNo. (PLEASE TICK ONE) Startin Australia □ GIFT SUBSCRIPTION: Month To Start Your Details Mr/Mrs/M s: Address: Postcode 2 years (24 issues) 1 year (12 issues) 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 $ _ __ ordebitmyO - II 0 11 D i V,1] I 1~11~ card expiry date Signature _ _ _ _ _ _ _ _ _ _ _ _ _!_ _ Gift Subscription Details Message: _ _ _ _ _ _ _ _ _ _ _ _ _ __ Mr/Mrs/Ms: _ _ _ _ _ _ _ _ _ _ _ _ __ Address: _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ Postcode_ __ _ "t:,r (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 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. FOR SALE ance. Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. 2.8Mb BACKPACK EXTERNAL disc drive for PC/XT/AT/PS1/PS2 etc. No internal connection . Runs off compatible printer port. Printer still supported. Simple installation. Suit laptops or any PC upgrade. 3.5-inch 2.8Mb drive accepts 1.4Mb and 720Kb discs. $599. 1.2Mb drive accepts 360Kb discs. $499. Prices include tax, postage & insur- 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, r-------------------------, I CLASSIFIED ADVERTISING RATES 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. 0 Visa Card 0 Master Card Card No. Signature _ _ _ _ _ _ __ _ _ _ Card expiry date_ _~/_ __ Name _ _ _ _ _ _ _ _ _ _ __ _ __ _ __ _ _ _ __ Street _ __ _ __ _ __ _ _ _ _ _ _ _ _ _ _ _ _ __ Suburb/town _ _ __ _ _ _ _ _ _ _ Postcode_ _ __ _ _ PROFESSIONAL KITS & products. Amplifiers, power supplies, test equipment, PC driven devices & surplus parts. Send SASE for list to: Al Younger, 5/22 Albert St, Edgecliff, NSW 2027. f I I I I I I I I I L-------------------------~ 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. PC VOICE RECORDER SOFTWARE. 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. $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. Enclosed is my cheque/money order for $_ _ _ _ or please debit my 0 Bankcard 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. OSCILLOSCOPE: Dual trace 200MHz HP1715A, delayed timebase, as new condition. One only $2100. Insurance & delivery: $25. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. VISIBLE LASER DIODES: Incredibly priced kit based on a 3mW 670nm visible laser diode. These are generally considered to have relatively infinite life and are all tested! Supplied with a heatsink, suitable drive electronics that works from a 3-4.5V battery, and a col- limator which will take a little setting up, no casing included. You could pay more than $300 for a laser pointer that uses these basic components. A bargain at $94 for all of the mentioned components. $5 certified p&p. Check availability before ordering. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. INFRARED LASER DIODES: Based on a brand new 5mW 780nm IR laser diode. Visible in low light so alignment is simple. Supplied with a heatsink, suitable drive electronics (works from a 34.5V battery) and a collimator which will take a little setting up, no casing included. Excellent for IR sights, data links, high quality audio links, security perimeter protection , etc. Experimenter's delight! Ask for simple related related circuit & PCB layout. Bargain at $49 for all the mentioned components. $5 certified p&p. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. LASER BARGAIN: Supplied with a 1 mW HeNe tube that has had a little use and is fully guaranteed. Supplied with our latest universal laser power supply. Bargain at $99 for the pair. Oatley Electronics, PO Box 89, Oatley, 2223. Phone (02) 579 4985. INFRARED NIGHT VIEWER: Not a complete kit but just the absolute essentials - an IR 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. SPECIALS: CRO valve 3BP1 $28; transmitter valve 083-300 $15; 3-port circulator 820-960MHz $58; fibre optic cable, 15 metres, $9. We stock a wide range of components and electronic valves. Mail order welcome. D. Dauner TRANSFORMER REWINDS ALL TYPES OF TRANSFORMER REWINDS TRANSFORMER REWINDS Reply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph: (065) 761291. Fax: (065) 761003. r "I MEMORY EXPANSION Prices at July 10th 1991 DRAM DIP ZIP. SIMM & SIP SPEED (ns) TYPE 120 2.20 1.80 100 2.35 2.00 2.50 6.10 80 70 4164 2.20 2.40 41256 2.75 41464 7.30 7.90 411000 36.00 1MBx4 (Static) 256K X 9 14.00 20.00 21.00 58.00 68.00 78.00 1MB x 9 272.00 299.00 4MB x 9 Simm Sockets 30 x 1 Vertical 1.70 Simm Sockets 30 x 2 Angle 3.50 Simm Sockets 30 x 2 Vertical 3.20 PELHAM \.. CO-PROCESSORS INTEL PCBs for all SILICON CHIP projects made to order. Prototype & kit repair service available. Hours 10-5 Wednesday to Friday, 9-12 Saturday. ETS, PO BOX 491, NOARLUNGA CENTRE, SA 5168. IIT 120.00 125.00 160.00 150.00 180.00 188.00 185.00 265.00 265.00 300.00 350.00 Sales Tax 20%. Overnight Delivery. Credit Cards Welcome 1st Floor, 100 Yarrara Road , Pennant Hills, NSW 2120. Tel (02) 980 6988 PRINTED CIRCUIT BOARDS CYRIX 8087 (fits all 8088's) 80287-10 80287-XLT (laptops) 80287-XL (up to 20MHz) 387SX16 387SX20 387DX16 387DX20 387DX25 387DX33 387DX40 Fax (02) 980 6991 ~ FIX-A-KIT $20.00 PER HOUR LABOUR 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION Service to most types of electronic equipment TECHNICAL ASSISTANCE HYCAL ELECTRONICS Design, Manufacture & Repair of Electronic Equipment Trading Hours 8am to 3pm, Monday to Friday (02) 633 5477 Phone: (08) 382 8919 SCANNERS MAX 1/0 Board Kit $149.00. Built & Tested $269.00. • 7 x Relays SPST 2 amps each • 8 x Switch inputs (TTL) • 1 x OAC (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. Electronics, 51 Georges Crescent (PO Box 42), Georges Hall, NSW 2198. Phone (02) 724 6982. Fax 725 7850. 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. CORNER REFLECTOR antenna kit. The original SILICON CHIP design. Outperforms commercial units at a fraction of the cost. Comes complete with all parts, cut and predrilled . Easy to as- Top quality Uniden, factory authorised dealer. Range from $210.05 for 50XL, covers 10, 6, 2, 70cm, 10 memories, ideal for amateur, to $475.52 for 200XLT, 200ch, covers all major bands, including 800-900MHz. Also the cheapest prices on marine equipment. Update to SSB for $238.26. Fibreglass 27MHz antenna $40.13. Post & pack $10 under$250. Cash, cheque& credit card accepted. TopCom Radio Communication, PO Box 336, Greensborough, Vic 3088. Phone (03) 883 9535. semble in under 1 hour. $65.00, including postage anywhere in Australia. Send cheque or money order to: BDK Audio , PO Box 139, Landsborough , Old, 4550. Phone(074)941928. COMPUTER BARGAINS this month. Floppy drives, quality Japanese , 360Kb $99.00; 1.2Mb $116.00; 1.44Mb $115.00; plus $6 postage. Ball/mouse with pad $39.00; optical mouse with driver, image software $75; plus $6.00 postage. VGA cards, 16bit/512Kb, exp. to 1Mb, $190.00. Tseng Labs 4000VGA continued next page OCTOBER 1991 95 Getting the PIF with Windows - continued from page 44 Advertising Index sign and comments can be included provided the comment line is preceded by a semi-colon(;). The following sections, not necessarily in this order, appear in the WIN.INI file: Windows - affects an assortment of elements in your Windows environment, including statements that can automatically load and run applications. Desktop - controls the appearance of the screen background (desktop) and the positioning of windows and icons. Extensions - associates specified types of files with corresponding applications. . Intl- describes how to display items for countries other than the United States. Ports - lists all available output ports. Fonts - describes the screen font files that are loaded by Windows. PrinterPorts - lists active and inactive output devices that can be accessed by Windows. Devices-lists active output devices that provide compatibility with Windows 2.x applications. Colors - defines colours for parts of the Windows display. Additional sections may be inserted by other applications - you need to consult the application's documentation for information on those sections,. When changes are made using the control panel, they are made to this file automatically. This file can be edited manually to make changes that cannot be made using the control panel. System.Ini This file (see Fig.4) primarily contains settings that allow you to customise Windows to meet your system's hardware needs. The following sections appear in the SYSTEM.INI file (again, not necessarily in this order). Boot - lists drivers and Windows modules. Boot.Description - lists the name of devices; can be changed using Windows setup. Keyboard - contains information about the keyboard. Non WindowsApp - contains information used by non-Windows applications. Standard - contains information used by Windows in Standard mode. 386Enh-contains information used by Windows in 386 enhanced mode. If a setting is changed incorrectly in SYSTEM.INI, Windows may become disabled the next time the program is started. Many settings in this file should be changed via the programs supplied with Windows (eg, Windows Setup, Control Panel, etc). Detailed instructions for altering the WIN.INI and SYSTEM.INI files are contained in text files usually located in the Windows directory. Next month, we look in detail at the options available and how you can customise the INI files. SC Market Centre - continued from page 95 card, 512Kb, exp. to 1Mb, $215.00 plus $6 .00 postage. 16MHz CPU 286 motherboard, hardware EMS, OK, $199.00 plus $10.00 postage. Mini tower case with power supply, $215.00 plus $15.00 postage. Phone for other bargains. Cheque and money orders only to: BOK Audio, PO Box 139, Landsborough, Old, 4550. Phone (074) 94 1928. ANTIQUE RADIO ANTIQUE RADIOS: vintage valve wireless sets, wind-up gramophones, phonographs, vintage musical ware, rare records, 45s, LPs, 78s bought, sold, 96 SILICON CHIP traded. Antique Sounds, 476 Pacific Highway, Belmont 2280. Phone (049) 45 9977. Open Thursday 10am-6pm, Friday 10am-5pm, Saturday 10am4pm. 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 Altronics ...................... .... 28-31,78 Antique Radio Restorations ...... 96 Av-Comm ... ...... ........... ...... ..... ... 89 Back Issues ... ... .......... ......... 40,41 David Reid Electronics ......... . IFC, 1 Dick Smith Electronics ............. 5-7 Electronic Solutions .................. 25 Electronic Toy Services ............. 95 Electronics World ....................... 11 Elmeasco .................................. 79 Geoff Wood Electronics ............ 67 Harbuch Electronics ............ .. .. ,. 78 Hycal Instruments ..... .. .............. 95 Jaycar Electronics ................ 45-52 J.V. Tuners ................... ......... .... 23 Kalex ......................................... 75 Oatley Electronics ..................... 71 Obi at Pty Ltd .......................... OBC PC Computers .... .. .................... 95 Pelham ..................... ....... ....... ... 95 RCS Radio ................................ 71 Resurrection Radio ................... 75 Rod Irving Electronics .......... 38,39 58,58,84,85 Silicon Chip Binders ..... .. .......... IBC Subscriptions ............................ 93 TopCom Radio Comm . .............. 95 Transformer Rewinds .... .. .......... 95 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. 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. SC SILICON CHIP BINDERS NO * High quality * Holds up to 14 issues * 80mm internal width * Gold printed with SILICON logo on spine and front cover CHIP These beautifuHy made binders will protect your copies of SILICON CHIP. We are especially pleased with their look and qillality. As soon as the first batch came in, everybody on our staff wanted them to store their .own personal issues. You will too. How To Phone (0~) 979 5644 Fax €02) 979 6503 ORDER: Made with a distinctive two tone green high-quality: vinyl specially selected for SILICON CHIP, and with heavy board covers, each binder holds a year's issues (the 14 issues of Vol. I or the 12 issues of Vol.2). Th~y will look really smaut on your bookshelf. ' To orde11 your binders, fill in the coupon in this issue and send it to SILICON CHIP, PO Box 139, Collaroy Beach, NSW 2097. Alternatively phone (02) 979 5644 and quote your credit card details, or fax yaur orders to (02) 979 6503. Price $All.95 plus $A3 each for postage and packing. (NZ postage and packing $A6.)