Silicon ChipJune 1992 - Silicon Chip Online SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: The oscilloscope - the everyday time machine
  4. Vintage Radio: The basics of receiver alignment; Pt.3 by John Hill
  5. Project: Multi-Station Headset Intercom; Pt.1 by Marque Crozman
  6. Project: Infrared Remote Control For Model Railroads, Pt.3 by Leo Simpson & John Clarke
  7. Feature: Computer Bits by Paul Lynch
  8. Serviceman's Log: From a snack to a 3-course meal! by The TV Serviceman
  9. Feature: SuperMac - Video Editing On The Small Screen by Darren Yates
  10. Feature: What's New In Oscilloscopes by Leo Simpson
  11. Subscriptions
  12. Project: Video Switcher For Camcorders & VCRs by John Clarke
  13. Project: Build A 15-Watt 12-240V Inverter by John Clarke & Darren Yates
  14. Back Issues
  15. Order Form
  16. Market Centre
  17. Advertising Index
  18. Outer Back Cover

This is only a preview of the June 1992 issue of Silicon Chip.

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

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Articles in this series:
  • The basics of receiver alignment (April 1992)
  • The basics of receiver alignment; Pt.2 (May 1992)
  • The basics of receiver alignment; Pt.3 (June 1992)
Items relevant to "Multi-Station Headset Intercom; Pt.1":
  • Multi-Station Headset Intercom PCB [01302921] (AUD $7.50)
  • Multi-station Headset Intercom PCB pattern (PDF download) [01302921] (Free)
  • Silicon Chip article scan, June 1992 - Multi-Station Headset Intercom Pt1 (AUD $10.00)
Articles in this series:
  • Multi-Station Headset Intercom; Pt.1 (June 1992)
  • Multi-Station Headset Intercom; Pt.2 (July 1992)
Articles in this series:
  • Infrared Remote Control For Model Railroads, Pt.1 (April 1992)
  • Infrared Remote Control For Model Railroads, Pt.2 (May 1992)
  • Infrared Remote Control For Model Railroads, Pt.3 (June 1992)
Articles in this series:
  • Computer Bits (July 1989)
  • Computer Bits (August 1989)
  • Computer Bits (September 1989)
  • Computer Bits (October 1989)
  • Computer Bits (November 1989)
  • Computer Bits (January 1990)
  • Computer Bits (April 1990)
  • Computer Bits (October 1990)
  • Computer Bits (November 1990)
  • Computer Bits (December 1990)
  • Computer Bits (January 1991)
  • Computer Bits (February 1991)
  • Computer Bits (March 1991)
  • Computer Bits (April 1991)
  • Computer Bits (May 1991)
  • Computer Bits (June 1991)
  • Computer Bits (July 1991)
  • Computer Bits (August 1991)
  • Computer Bits (September 1991)
  • Computer Bits (October 1991)
  • Computer Bits (November 1991)
  • Computer Bits (December 1991)
  • Computer Bits (January 1992)
  • Computer Bits (February 1992)
  • Computer Bits (March 1992)
  • Computer Bits (May 1992)
  • Computer Bits (June 1992)
  • Computer Bits (July 1992)
  • Computer Bits (September 1992)
  • Computer Bits (October 1992)
  • Computer Bits (November 1992)
  • Computer Bits (December 1992)
  • Computer Bits (February 1993)
  • Computer Bits (April 1993)
  • Computer Bits (May 1993)
  • Computer Bits (June 1993)
  • Computer Bits (October 1993)
  • Computer Bits (March 1994)
  • Computer Bits (May 1994)
  • Computer Bits (June 1994)
  • Computer Bits (July 1994)
  • Computer Bits (October 1994)
  • Computer Bits (November 1994)
  • Computer Bits (December 1994)
  • Computer Bits (January 1995)
  • Computer Bits (February 1995)
  • Computer Bits (March 1995)
  • Computer Bits (April 1995)
  • CMOS Memory Settings - What To Do When The Battery Goes Flat (May 1995)
  • Computer Bits (July 1995)
  • Computer Bits (September 1995)
  • Computer Bits: Connecting To The Internet With WIndows 95 (October 1995)
  • Computer Bits (December 1995)
  • Computer Bits (January 1996)
  • Computer Bits (February 1996)
  • Computer Bits (March 1996)
  • Computer Bits (May 1996)
  • Computer Bits (June 1996)
  • Computer Bits (July 1996)
  • Computer Bits (August 1996)
  • Computer Bits (January 1997)
  • Computer Bits (April 1997)
  • Windows 95: The Hardware That's Required (May 1997)
  • Turning Up Your Hard Disc Drive (June 1997)
  • Computer Bits (July 1997)
  • Computer Bits: The Ins & Outs Of Sound Cards (August 1997)
  • Computer Bits (September 1997)
  • Computer Bits (October 1997)
  • Computer Bits (November 1997)
  • Computer Bits (April 1998)
  • Computer Bits (June 1998)
  • Computer Bits (July 1998)
  • Computer Bits (November 1998)
  • Computer Bits (December 1998)
  • Control Your World Using Linux (July 2011)
Video Editing On An Apple Macintosh AUSTRALIA'S DYNAMIC = ~-- ELECTRONICS_MAGAZINE~ • ~ ~'t. -. I. SERVICING - VINTAGE RADIO - COMPUTERS - AMATEUR RADIO - PROJECTS TO BUILD WHAT'S NEWIN OSCILLOSCOPES? . r--. C) O> CL en z ci z z BONUS ,_ , DICK SMITH ELECTRONICS CATALOG 0 ~ "" ~ _J en Multi-Station ~ Headset Intercom Build A 15-Watt 12-240V Inverter ~ ~ Run mains appliances from a 12V battery (f) <( ::::, Provides clear communications in high-noise environments 0 w a: ; w a: Video Switcher for Camcorders & VCRs Building the IR Model Railroad Controller Within budget. Without compromise. With HP basic instruments, performance costs less than you expect. Now you don't have to accept trade-offs in a basic test instrument. Because HP offers the performance you want at prices you can afford. ~-~~ _ What about a digital multimeter for bench or system use? The rugged 6 or 61/2 digit HP 34401A does both with uncompromised performance for less than $1,635. ... k4<>1A -- / /.998? □ '• _.J . ~~ A Need a dual-range output power supply? The HP E36 10 Series makes choosing a 30 Watt DC power supply easy-especially when you consider the low noise and value for money at ar ound $460. t00 llH1 . -. - ••••Ff . ltTir 'lJL I!EE! • r1 ~ '!l~;=9~ ~ -. ~ :~ 'L -~ - !ll'' L t::: tJ ,;;;;;,,.;;;-:,r·--:;'~ «= . ·; =?" Ee . ':;. {,Ill C =-·ill: ~~·1 --.- 1 " You won't find a better 100 MHz digitizing scope than th e HP 54600 Series. It combines an analog look and feel with digital trouble-shooting power for around $4,040 (2-ehannel) or $4,695 (4-ehannel). At less than $5,780, the HP 4263A LCR Meter lowers the cost of high precision lO0Hz to l00kHz benchtop and system component measurements. And the 8-function HP E2373A is just one of the HP E2300 Series 3 1/2 digit handhelds priced from $160 to $3 10. For more information, call our Customer Information Centre on 008 033 821 or Melbourne 272 2555, and we'll send you a data sheet that shows how affordable performance can be. A Better Way. F/,'u9 HEWLETT ~~ PACKARD *Prices exclud e sales tax. _ ri'. - - ~-- .,_ _-,_ , .... -- _ Vo/.5, No.6. June 1992 '·~· ·V.': ..",~ THIS MULTI-STATION headset intercom is designed to provide clear communications in highnoise environments. Find out how to build it by turning to page 16. FEATURES 42 SuperMac - Video Editing On the Small Screen by Darren Yates It runs on any Apple Macintosh computer 53 What's New In Oscilloscopes? by Leo Simpson A look at the latest models and their features PROJECTS TO BUILD SOLVE YOUR video dubbing problems with this 3-way video switcher. It's specifically designed for use with camcorders & VCRs. Details page 68. 16 A Multi-Station Headset Intercom by Marque Crozman Build it for high-noise environments 24 lnfrared Remote Control For Model Railroads, Pt.3 by John Clarke Third article completes the construction details 68 Video Switcher For Camcorders & VCRs by John Clarke Let's you dub from any of three video sources 82 Build A 15-Watt 12-240V Inverter by Darren Yates Use it with telescope drives & camcorder battery rechargers SPECIAL COLUMNS 6 Vintage Radio by John Hill The basics of receiver alignment, Pt.3 32 Computer Bits by Paul Lynch A look at hard disc drives THE SERVICEMAN made a 3course meal out of a snack this month. So what went wrong? The story starts on page 36. 36 Serviceman's Log by the TV Serviceman From a snack to a 3-course meal! DEPARTMENTS 2 Publisher's Letter 4 Mailbag 41 News 61 Product Showcase 65 Subscriptions Page 66 Circuit Notebook 88 Back Issues 90 Ask Silicon Chip 92 Notes & Errata 93 Order Form 94 Market Centre 96 Advertising Index \-!:-~\..~: .. YOU CAN USE THIS 15W 12VDC-240VAC inverter with a camcorder battery recharger or to control a telescope drive motor. Turn to page 82 JUNE 1992 1 Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) PUBLISHER'S LETTER Technical Staff John Clarke, B.E.( Elec.) Robert Flynn Darren Yates Reader Services Ann Jenkinson Sharon Macdonald Sales & Marketing Mgr. Sharon Lightner · Phone (02) 979 5644 Mobile phone (018) 28 5532 Regular Contributors Brendan Akhurst Jennifer Bonnitcha, B.A. Garry Cratt, VK2YBX Marque Crozman 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. A.C.N. 003 205 490. All material copyright ©. No part of this publication may be reproduced without the 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, see the subscription page in this issue. Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. Editorial & advertising offices: Unit 1a/77-79 Bassett Street, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 979 5644. Fax (02) 979 6503. ISSN 1030-2662 2 SILICON CHIP The oscilloscope - the everyday time machine This month, we have a feature article on oscilloscopes. This takes a look at some of the features of current model scopes, both analog and digital. It really only just touches on the subject, giving a glimpse of what these remarkable measuring instruments can do. When you think about it, we take the oscilloscope for granted. Want to take a look at a signal? Simple, just grab a probe, connect it up, flick a few switches and there it is on the screen. But what may be portrayed on the screen is often happening so fast that it is impossible for the human brain to really appreciate. Say you have a signal on the screen with a frequency of 100 megahertz. That's an absolutely routine frequency but you can display it easily on many scopes these days so that you can see the actual waveform, not just a signal envelope. Think about that waveform. Each cycle of the waveform on the screen is taking place in just ten nanoseconds. Such a time interval is so short that if were to regard a nanosecond as a second, an hour of our lifetime would last more than 100,000 years! And yet we look at those minute slices oftime as though they were nothing more remarkable than a pencil sketch. Which in a way is what they are; an accurate sketch sample produced automatically by the flying electron beam behind the screen. Think about how fast the electron beam has to move in order to accomplish that task. It is fairly easy to calculate how fast it is deflected up or down the screen but think how much faster it is going as it hits the back of the screen. But a 100MHz scope is just routine these days and it is only scopes that go up into the Gigahertz region that are regarded as really special. That's an order of magnitude better - or more. Truly then, today's oscilloscope is a veritable time machine - not one that allows us to travel forward or backwards in time but one which allows us to divide time into portions so small that time becomes meaningless. Think about that the next time you hook up your scope for a routine measurement. Leo Simpson LAB4 Frequency Counter, Function Generator, D.M.M., Power Supply, 4 in 1 Unit FEATURES ■ One instrument with ■ F requency Counter, Four Test and Measuring Systems. Function Generator, Digital Multimeter and Power Supply. ■ Ideal for Laboratory . Production Line and R & D Engineer's Working Bench. ■ High Accuracy and Low Cost for Specialists and Hobbists. ■ Unique Performance to Save Space. ■ Light Weight and Attractive Design . ■ Simple and Easy Operation. ■ Full Overload Protection. GENERAL ■ Power Requirements: 115/240V AC 50/80Hz. ■ 120 VA with Full Loaded Power Supply. ■ Size: 375(W) x 180(H) x 340(0) mm. ■ Weight: 11Kg (approx.) #1 Frequency Counter #2 Function Generator #3 Digital Multimeter #4 Power Supply ■ Range: ■ ■ 3 1/2 Digit LCD Display. ■ Auto/Manual Range. ■ DC AC v. Ohm's, DC A, ■ Basic Ac curacy:• /- 0.5% ■ Data Hold function. ■ 1Hz - 100MHz Sensitivity: 1Hz - 80MHz: 15mV 80MHz • 100MHz: 25mV . ■ Resolution: 0.1. 1, 10, 100Hz. ■ Gate Time: 10ms. 100ms. 1s, 10s. ■ Display: 8 digits LED. ■ Sine, Square, Triangle, Skewed Sine. Pulse, TTL Level Square. ■ Frequency: 0.02Hz • 2MHz. ■ Output: 0.1 Vpp • 20 Vpp. ■ Linear and Log Sweep: Internal: 20ms - 2s. External: 100. 1 (by VCF) ■ Output Impedance: 50/600 ohm. v. ■ 3 1/2 Digit LCD Display V & A. 11- 0 • 50V , 0.5A max. 12- 15V, 1A (f ixed). ■ Output 13. 5V, 2A (fixed). ■ Full Over Current Protection. ■ Ripple: 11- 1mV max. Ripple: 12, 13. 2mV max. ■ Load Regulation: 11- 0 .01% • 5mV ■ Out pu t ■ Output AC A . Memory Mode for Zero Ohm adjustment and Relative function. Impedance: 10M ohm. ■ Input Only $837.00 incl. tax. $722.00 ex. tax. DMM02 Digital Pocket Multimeter 12 months Warra nty VSI Easy-Connect Phone-Fax/Line Sharer ■ ■ Auto Ranging 3.5 digit LCD display ■ AC/DC volts ■ AC/DC amps up to 10A ■ Ohms range ■ 20mA & 200mA range ■ Manual ranging ■ Data Hold ■ Continuity Beeper ■ Memory function ■ Includes Test Leads The First Truly Intelligent PHONE-FAX LINE SHARING DEVICE NO NO NO NO NO Confusing Voice Messagei,3. Periods of Silence. Unusual Dial Tones. Delays. Frustrated Callers. The EASY -CONNECT is totally transparent. Your callers will never know it's on the line ! Save Installation and rental costs for a separate lln e. Switches Incoming Fax calls automatica lly on receipt of calllng Fax tonss. 0 fn~\~~I~ ~~~l~~:io:~TlN\,8~~~~ l~oCKE T using supplled connectors. DOES NOT REQUIRE EXPENSIVE TELECOM INSTALLATION. Adds HOLD FACILITY to all phones. Puts a c all on hold from any phone. Manual Transfer to Fax before, during or after vo ice conversation . Can lnterupt a Voice conversation, to send or receive a Fax, then resume. works with or without an Answering Machine. Pulse/Tone dlal compatlab l e. Will operate with Fax, Phone, Modem and A nswerin g Mach i ne on on e line. No restriction to the number of extensions or other devices connected to It . Compact Design, being a llttle larger and heavier than a packet of cigarettes. Proven Rellablllty backed up with a 2 YEAR Exchange Warranty. Also works with Commander, Keyphone or PABX (technlcal lnatallatlon requ'd) The EASY-CONNECT Is compatible with the changing needs. Provides Lightning protection for the Fax and other devices connected to It. Made In the U.S.A. Telecom Australla Permit Number: AS0 /148/0342. Size: 85mm x 90mm x 33mm. Wgt: 225g . Limited Stocks - Be Quick I For more information on this product ring Jeff on (02) 267 1885 Now $39.95 Only $399.00 was $99.95 Save $60.00 BLUE Led's Cl-118A 20MHz 2 CH. Oscilloscope ■ ■ Luminous Intensity o 20mA: 7mcd ■ F orward Voltage: 2.7V (min.), 3.0V ■ Reverse Voltage: 5.0V. screen. ■ Dimensio ns: . 9 Now available at an affordable price! Frequency up to 20MHz. ■ Sensitivity: SmV /DIV to 10V /DIV. ■ Sweep: 0.5us/DIV to 50ms/DIV. ■ Includes 2 x 1:1 10:1 probes. ■ 12 months warranty. ■ 4· 2 year Warranty 212 x 133 x 338mm. =~~~~i~:~~~h~~~~~~o deg. (min.). 14mcd (typ.) (typ.), 3.5V (max.) o 20mA _ ■ Available in 3mm and 5mm case. ■ Case Colour: water-clear. 3mm Part No.: 1 to 9: $3.95ea. 5mm Part No.: 1 to 9: $3.95ea. Limited Stocks at this price ~ I<::'::.. : : '-T--. , .-.., - ~ L-934BC (BLUE) 10+ $3.55ea. 50+ $3.20ea. 100+ $3.00ea. L-53BC (BLUE) 10+ $3.55ea. 50+ $3.20ea. 100+ $3.00ea. PH20-5PK Soldering Iron Set my-power 200 12V to 240V inverter Kit Includes:- Turn your car or boat battery into 240V AC mains power ■ Scope 20W Iron ■ Resin Core Solder ■ Flat Head Driver ■ Ph illips Head Driver ■ Stand and Sponge Only $29.95 I ■ Input : 12V DC Output: 240V AC 50Hz (cont.). 200W (peak). 400W (int.) ■ Fully protected ■ S ize: 50mm x 135mm x 74mm ■ ■ 140W Only $199.00 ~ David Reid 127 York St, SYDNEY 2000 Ph: (02) 267 1385 ~ Electronics P.O. Box Q103,SYDNEY 2000 Fax: (02) 261 8905 A.C.N. 001-372-372 12 months Warra11ty Postal Charges $5 - $25 ......... $4.00 $28 - $50 ...... $8 .00 $51 - $100 ..... $7.00 $101 - $499 .. $9.00 $500 • ........ .... FREEi MAILBAG Information on inverter cores With reference to "Ask Silicon Chip", April 1992, and the letter from C. K., Illawong, NSW, the following information may be of assistance. To place a µH value beside every coil in your circuits would be misleading, inaccurate, and could force constructors to waste many hours on unproductive coil winding. Concerning the inverter transformer used in the fluorescent light inverter (February 1990), the number given in the original text is ETD29, and I thought it readily available from kit suppliers. The full Siemens part numbers for this assembly are: Core (half) B66358-G-X127 Bobbin B663559-A1013-T1 Clip (one) B66359-A2000 This is a standard stock line for our company and is available ex-stock at $14.00 for the complete assembly as per the kitset. Concerning the 4322 -0222-1500 Philips pot core used in the Solar Charger (November 1991), AAARGH! Philips parts numbers! The correct part number for a core half for this item is 4322-020-21500 and unfortunately this is, as your reader has found, rather a "non standard" industry standard ferrite material. The Philips Soft Ferrite Handbook (1973) is not very specific on the critical parameters of this grade and as far as we can determine, there is no direct material grade replacement available from Neosid, Siemens or TDK. Our research suggests that the Philips #Hl material has the same permeability but slightly different Al characteristics, and would be a very good starting point for a replacement grade. We also have 3D3, 4C6 (AlA), and 4C6 (A25) in Philips product and several Neosid materials in stock in the 18/11 size. All are ex-stock and similarly priced at around $7.00 for the complete assemblies. Ferrite and iron powder products are probably one of the hardest and most complex components encountered in electronics when choosing a 4 SILICON CHIP suitable grade for construction or replacement. We reference some eight different data books when faced with this problem. For further reading, I advise your reader to purchase a copy of the Neosid handbook (ex-stock, $29.00). Whilst this won't solve all his/her problems, it will answer many questions! A. Frolley, All Electronics Components, Melbourne, Vic. LISNs revealed Line Impedance Stabilisation Networks (LISNs) are used extensively in EMI compliance checking. We as manufactures use these regularly to ensure EMI compliance of our medical ultrasound products. I hope this eases the pain of not knowing what an LISN is, as voiced in your review of the book on page 33 of the February 1992 issue. Graham Bloom, R&D Dept, Ausonics Pty Ltd, Lane Cove, NSW. A vote for microprocessor kits I respond to your answer to a letter (Ask Silicon Chip, March 1992) headed "Microprocessor kits wanted". I'm amazed that your attitude seems to be so negative in respect to do-ityourself micro systems. More than 80% of domestic equipment these days is micro based. Indeed your magazine is always full of articles utilising PCs. Let's face it, PCs are pretty useless when it comes to a dedicated system (robotics, industrial control etc). We are currently reviving a do-ityourself Z80 micro that was presented by another magazine some years back. Our application is a dedicated one where inputs control various outputs with memory requirements. I for one am sick and tired of the endless stream of"egg timer, car light extender, model railways lights" type projects. I understand that they have a place but a micro-based project could fill all of these project requirements. SILICON CHIP, PO Box 139, Collaroy Beach 2097. With a name like SILICON CHIP, I can't think of a more appropriate project for your magazine. The current Twin 50 stereo amplifier project in your magazine is excellent. One area of possible improvement however would be to have a removable cover on the bottom of the chassis for easy service access. M. Kalinowski, Cairns Electronics, Qld. Microprocessor kit a good idea I totally agree with J. G. of Springvale in the March edition of SILICON CHIP concerning his suggestion for a microprocessor kit. As he stated "I have been working in the sales of electronic equipment for over three years. I believe there is a real need for one or more microprocessor kits". Obviously he has had many inquiries to prompt him in making his proposal. I have built a home weather station using a Z8671 driving an LCD display. The main board design came from the July 1981 edition of Byte magazine, with an add-on AID converter circuit appearing the following month. Byte magazine has had some excellent projects in the past - a review may give your staff some ideas to consider. The Z8671 is still readily available and is ideal for novice users. It has BASIC/DEBUG masked, 4Kb of program memory, an RS232 serial port and two parallel I/O ports. To program it, one need only connect a terminal (or PC emulating a terminal) and enter BASIC commands. Once the program has been proven, it can be transferred to EPROM for a permanent application if required. The Z8671 is by no means the only microcontroller available; I only 'offer it as an example because I have had good results. True, the PC has made a big dent in controlling various things but who wants to run a machine continuously? I don't want my screen burning away and the hard disk operating non-stop (not to mention a huge overkill for the task)! So a potential does exist for a small micro kit that could fulfil a score of tasks (reference to Byte will show that the author, Steve Ciarcia, used the Z8 for about a dozen different projects). Also, don't overlook the potential to learn about micra's and interfacing here. In closing, I would like to suggest that SILICON CHIP incorporate in future projects the intelligent LCD display modules that are now available at modest cost. The type I have in mind usually have about 16 to 24 characters and one or two lines. Keep up the level of excellence in your magazine. W. J. Sherwood, Alexander Heights, WA. Telephone call timer project Please note that the information presented in the opening few paragraphs of the Telephone Call Timer Project is inaccurate. IDD is not charged in increments of one minute or portions thereof as described. IDD charging is based on "meter pulses" at $0.25 per pulse. The pulse rate is determined by the tariff set for the time of the call (ie, Off-Peak or Normal rate) to a particular country. For example, if the rate to country A is $2/min (full rate) and one speaks for 10 seconds, the charge is 50 cents. Dave Stimson, Manager, Telephone Service Performance, OTC,NSW. ZBO microprocessor kit available In answer to J. G. of Springvale, Victoria (Ask Silicon Chip, page 92, March 1992), I would like to advise him that I have had a Z80 Development Kit available for over two years. This communicates via the standard printer port of an IBM-type PC. It has been advertised in SILICON CHIP and other magazines periodically since February 1990. This kit uses the same CPU board as my Moving Message board (no longer supported) which was published in this magazine from March to June 1989, and my Printer Buffer board published in this magazine in October 1989. I am currently writing a simple Integer Basic Interpreter for it, as I feel this will have wide appeal with novices, educational institutions and students. The ratio of analog to digital articles printed in SILICON CHIP doesn't appear to reflect advertisers interests. Apart from some 1/0 conversion logic, with the imminent digital sound and digital video technology explosion, by the year 2000 very little will be known, need to be known, or published on analog circuits. They may appear in a column like John Hill's Vintage Radio. Perhaps interested readers will write in if they would like to see more computer hardware related articles in this magazine. D. McKenzie, Tullamarine, Vic. Selective calling project wanted As a suggestion for a future project, could one of your technical guru types investigate a selective calling project. With the cost of 3 x 4 keypads now only a few dollars and DTMF encoding and decoding chips around $7 dollars, this project should fare quite well compared to commercial units. In the past, only single tone encoder/ decoders have been described. If more than one person in the area has seen and constructed the project this is a problem, so a five or six-tone device would be nice, utilising a touch tone keypad to input the codes. The unit could be used on both HF and UHF CB and amateur radios to open muted sets. This would not require the sets to be modified, as the decoding relay contacts could be in the speaker leads, and the encoding via the mic input. Having a decoder with several outputs could allow people to set a CB up in their home and remotely operate devices from across town. Maybe even a small decoder could be devised, so a small company could use CB for a small area network. R. Masterton, Macquarie Fields, NSW. Thermostatic switch for car radiator fans Your "Thermostatic Switch For Car Radiator Fans" in the March 1992 issue interested me as I am in the middle of resurrecting my wife's 1977 Corolla and the notion of converting . to a thermostatic electric fan is quite a tempting one. However, I would like to make a couple of observations. Firstly, I'm a great believer in "sensible censorship". I really don't think that Mr Clarke should have even mentioned that the controller described is capable of driving some fans directly itself. In keeping with common auto engineering practice, I feel it's much more desirable to always switch such things with a relay. The other advantage is that in the instance of failure, anyone troubleshooting "on the road" is going to have a better chance of figuring it all out if they see that relay. In fact, an externally mounted auto type relay might be preferable for that reason. That leads me to my next point: our other car is an 1986 Telstar, fitted with twin thermostatic fans. They operate on the "failsafe" principle they are connected to the "normally closed" contacts of the relay, so in the event of a failure in the relay coil or thermostatic switch, the fan will run constantly - a preferable alternative to a fan that will not switch on at all. It is worth considering that the person who fitted the controller will not always be driving, so surely it's better to play safe? Looking quickly at the circuit with my very limited knowledge, it would appear possible to alter it by changing Q3 to a component that would energise the relay in the "off" state. Alternatively, you could use two relays relay 1 would , via the "normally closed" contacts, energise relay 2 in the fan "off" state. The fan would be connected to the "normally closed" contacts of relay 2, so in the event of any failure within the controller, the fan would at least be running. I am sure there is a neater way of doing this with Q3. I really do enjoy your magazine and have foµnd it very educational. P. Bradstock, Epping, NSW. Comment: the Thermostatic Switch should be vezy reliable since it's based on a well-proven ignition circuit. An inverter stage could be added in front of Q3 for fail-safe operation but this would also add to the circuit complexity. JUNE 1992 5 VINTAGE RADIO By JOHN HILL The basics of receiver alignment; Pt.3 Last month, we started to align our hypothetical ·. superhet receiver and had progressed as far as the intermediate frequency transformers. We can now proceed with the rest of the job & that is to align the aerial and oscillator circuits so that they track accurately. We shall start with a typical receiver from the mid 1930s; one with a compression type padder capacitor and two trimmers - aerial and oscillator. Receivers that have a fixed padder and an adjustable iron core in the oscillator coil require a different approach. Due to the fact that most, if not all, radio stations on the broadcast AM band are no longer transmitting on their original frequencies, exact dial calibration is not really possible. It is therefore quite reasonable to ignore the station positions as marked on old dials and set the dial pointer to correspond to the kilohertz calibrations (naturally, the dial will be marked in kilocycles). Most old dials have a frequency scale on them somewhere. However, as i' live in Victoria and most of the Melbourne stations are still quite close to their original frequencies, I set up my receivers to tie in with the Melbourne stations and, accordingly, zero in on 3AR at the low frequency end of the dial and 3XY at the high frequency end. An RF signal generator is an invaluable aid when aligning old radio sets. The RF signal from the generator is injected into the receiver via the aerial and earth terminals. 6 SILICON CHIP These settings correspond fairly closely to the 600kHz and 1400kHz frequencies that many radio manufacturers suggest as alignment points. Aligning a set in such a manner works in fairly well with some other stations and SAN and 2SM are two that come to mind. In any case, the alignment frequencies should not be too close to the ends of the band, otherwise tracking may be degraded in the centre of the band. To carry out the next stage of our receiver alignment, the radio frequency (RF) generator is connected to the aerial and earth terminals and the frequency set to whatever has been decided as a reference point at the low frequency end of the dial. In my case, this is 621kHz which is 3AR's frequency. The next step is to tune the receiver to the RF signal with the receiver volume control set to maximum and the generator output adjusted to give a low scale reading on the output meter (see last month's article). The output meter is simply connected between the output valve anode and chassis. Tracking adjustment using a variable padder capacitor - and without the advantage of an iron core in the aerial coil-is one of the trickier alignment jobs. The problem is that, without any means to adjust the aerial circuit at the low frequency end of the band, the position at which it resonates· for a given frequency is completely beyond the operator's control; we have to accept it "as it comes". More importantly, we have to make the oscillator circuit tune the frequency at this same spot. But, because the oscillator circuit has virtually total control, we have no simple way of knowing where the aerial circuit is resonating; we have to search for it on a trial and error basis. If a superhet radio has a 3-gang tuning capacitor, it usually also has a stage ofradio frequency amplification. The more tuned circuits there are, the more important accurate alignment becomes if the set is to perform correctly. An RF (radio frequency) stage should be adjusted only after the aerial and oscillator circuits have been aligned. Note that this particular receiver has a dust cover over the tuning capacitor. the signal doesn't move, then the wrong trimmer is being adjusted. Having done this, adjust the aerial trimmer for maximum output on the output meter. The above procedure should now be continuously repeated at both ends of the dial until no further improvement is possible. If the receiver has a stage of radio frequency amplification, then the section of the gang that is connected to the RF stage must also be tuned. It is best to adjust this trimmer after the aerial and oscillator trimmers have been set. And that's it; the receiver is aligned! Iron-core slugs / If you don't have an RF generator, the IF transformers should be adjusted for maximum volume. However, there is no way of knowing as to whether or not the IF transformers finish up operating at their intended frequency. Hence the "rocking" technique used on these early sets. The procedure is to first note the reading on the output meter, then make a small adjustment to the padder and retune the gang for maximum output. If the reading increases, you make another adjustment in the same direction. If not, you adjust the padder in the opposite direction. These small trial and error adjustments are continued until maximum output is achieved. If dial calibration is required, it can be done after the above adjustment, by adjusting the dial pointer position or the dial drum on the tuning gang shaft. Next, set the RF generator to the chosen frequency at the high end of the dial (in my case, that's 1422kHz, 3XY's frequency). This done, tune the receiver to the signal and check to see if the frequency matches with the dial and dial pointer. If it doesn't, the pointer position can be moved by adjusting the oscillator trimmer one way or the other. Note that only the oscillator trimmer will shift the signal position. If For a superhet with iron cores or slugs in both the aerial and the oscillator coils, the procedure is a little different. In fact, the development of coils with adjustable iron cores was a major breakthrough in its day, making possible simpler, more precise, and more stable adjustments. These sets have no adjustable padder capacitor - instead, they use a fixed capacitor. The tracking is adjusted using the iron cores. The first step is to set the dial pointer to the extreme low frequency end of the dial scale - or to a "pointer" mark if there is one - with the gang fully in mesh. This done, set the station calibration at thl;) low frequency end of the dial by adjusting the oscillator coil. The station position at the high frequency end of the dial is now adjusted using the oscillator trimmer. Repeat these two steps until no further improvement is possible, then go back to the low frequency end again and tune for maximum output by adjusting the aerial coil slug. JUNE 1992 7 stronger signal and/ or the one closest to the appropriate dial calibration. However, be aware that there are a few variations with shortwave receivers and multi-band sets can be a bit difficult to work out. No instruments Small dial pointer adjustments are catered for in this old Radiola by the elongated slots in the pointer bracket. Many pointers can also be slid along the dial cord. Large dial pointer adjustments can be made by rotating the dial drum a few degrees. The pointer position is set at the low frequency end of the dial. Finally, adjust the set for maximum output at the high frequency end of the dial using the aerial trimmer. Repeat these last two steps until no further improvements are possible. The job is now complete. A useful tip - always adjust slugs an d/or padder capacitors at the low frequency end of the dial and trimmer capacitors at the high frequency end. Do not confuse the oscillator slug with the IF transformer slugs. If a receiver has a shortwave band, it should also be re-aligned as there will be trimmer adjustments for the shortwave coils. Usually there is no padder adjustment, the padder capaci8 SILICON CHIP tor being a fixed one. In some cases, the coils may be fitted with iron slugs. Alignment instructions for shortwave receivers usually suggest that the RF generator be set to around 12MHz and the trimmers adjusted accordingly. The shortwave oscillator trimmer will move the signal's position on the dial and the shortwave aerial trimmer is then adjusted for maximum output. Be aware that a strong shortwave signal can produce a double spot condition; ie, the appearance of the same signal at two points on the dial, separated by twice the IF (typically 910kHz). The correct one will be the It's also quite possible to align a radio receiver without the use of an RF generator or output meter. The process is similar to the foregoing but with a few minor differences. As previously explained, when aligning with an RF generator, the IF transformers are adjusted before the aerial and oscillator circuits. When aligning without a generator, the procedure is often reversed- not that it really matters much. Incidentally, the time of day has a lot to do with the success of the operation and a middle of the day tuneup will be much easier than an afterdark job. At night, there are too many distant and often powerful stations jostling for their share of dial space. During daylight hours, only local stations can usually be received and they provide a much steadier signal, although a distant steady signal is what's really required. First, tune to a suitable station at the low frequency end of the dial and adjust the oscillator/aerial tracking as already described. Without the benefit of an output meter, this is best done at low volume, as the ear is more sensitive to variations in soft sound than loud sound. Alternatively, you can adapt your multimeter for use as an output meter as described last month. When the optimum tracking adjustment has been found, shift the dial pointer so that it lines up with the station's frequency if it doesn't already do so. Now move to the high frequency end of the dial and use the oscillator trimmer to move the station to the desired position. This done, adjust the aer,ial trimmer for maximum volume and the RF trimmer too if the set has a stage ofradio frequency amplification. Repeat these steps until no further improvement can be obtained. IF transformers When aligning the IF transformers, there is no way of knowing whether or not the transformers are set close to . their designated frequency. If the trans- RESURRECTION RADIO Vintage Wireless Specialists This old Radiola dial from the mid 1930s is marked in both kHz (K.C.) at the bottom and metres (M.) at the top. 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, Parts are available for the enthusiast, 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 catalog, WANTED: Valves, Radios, etc. Purchased for CASH Call in to our showroom at.' 51 Chapel Street (PO Box 1116), Windsor, Vic 3181. Telephone: (03) 529 5639 Silicon Chip Binders !i' r 'the two trimmers on the lefthand side of this chassis are for the broadcast band, while the trimmer at right and another that's hidden from view are for the shortwave band. Determining which trimmer does what is often a trial and error process and once known, they should be marked for future reference. formers are as originally adjusted by the radio manufacturer, there is little to worry about. However, if they have had their "screws tightened up", then there could be problems. Tuning IF transformers without the aid of an RF generator is a bit of a guessing game because they can only be adjusted for maximum volume. Whether or not the transformers end up tuned to their intended operating frequency will remain unknown. For sets with a shortwave band, all one can do is tune into a reasonable strength signal (somewhere around 12MHz) and adjust the shortwave aerial trimmer for maximum volume. It's not hard to put the dial alignment out if the oscillator trimmer is given a few turns by mistake. It is a good idea to mark the original positions of the adjustment screws in case one gets lost. Receiver alignment is a very important aspect of vintage radio restoration. The full potential of any superhet radio can never be attained unless the IF transformers are correctly adjusted and the aerial and oscillator circuits are tracking accurately. Basically, that's what receiver alignment is all ~o~. SC These beautifully-made binders will protect your copies of SILICON CHIP. They are made from a distinctive 2-tone green vinyl & will look f}reat on your bookshelf. Price: $A11.95 plus $3 p&p each (NZ $6 p&p). Send your order to: Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or fax (02) 979 6503; or ring (02) 979 5644 & quote your credit card number. JUNE 1992 9 3 year warranty! 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C21082 ..•.•••••••..•.•••••••..•.. $199 10+ C20092 $9.95 $9.50 Size: 210 JI 11.5 X 30m C20094 $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 Size : 216 x 25.4 x 30m C20100 $11.115 $11.50 Size : 216 x 24.4 x50m The Fonron CPF Filtered Electronic SP.1ke Protector provides a protective eleC1.ornc barrier for m1crocompu1ers printe rs. telephone systems and modems electronic typewriters . audio and slereo ;5ystems and other sens,uve electron,c equrpmenl CPF s superior circuitry design and sem, conductor technology responds instantly to any potentially da maging over-voltage . ensuring sale trouble free ope ration 10+ C22036 ... .. $ ·12 .95 $11 .95 • MXBO, FX80, RXBO, FXBOO, MX70, MX80. LXBOO. C22031 .... $10.95 $10.50 • MX100, FX100, RX100, L01000 C22002 ..... 512.95 $11.95 • LXBO C22003 .......$9.95 $9.50 • CITOH 851 O - 1550 C22051 ..... $13.95 $12.50 NATIONAL PANASONIC KXr.t110 PRINTER RIBBON C22034 .. ....................... $11.95 CatX10088 $69.95 A s1fl1ple way ol momtonng AS23i interface lead activity ln!erloce powered. pocket s,ze !or circuit testing . momtonng and patching 10 sig na l powered LED"s and 2 spares 24 switches enables you to break out circuits or reconfigure and patch any or all the 24 active posi tions SPECIFICATIONS : Connectors : 0 825 plug on 80mm t1bbon cable and 0825 socket Indicators : Tricolour LED s !or TD RO . RT S. CTS. OSR. CD . TC AC . OTA . iEJ1C Jumper Wires: 20 tinned end pieces Power : lnlerlac:e power Enclosure : Black high impact plastic Dimensions : 85 x 95 x 30mm X15700 Microsoft compatible streamline design an amazing $29.95. TOP OF THE RANGE MINI TOWER CASE 200 X 415 x 330mm ' with 200w power supply . x11100 .................. ........ $199 RITRON EXECUTIIVE CASE X11089. Includes power aupply.•..• $119 NEW STYLE MINI TOWER CASE WITH POWER SUPPLY X11103 .................... $149 OUT NOW!! PICK UP YOUR FREE COPY AT ANY OF OUR STORES. : I .I I I I I L---------------J r--------------- Mouse Image onl ..... $99.95 SUPA PRICE ON DOS 6.0 NOW ONLY IBM COMPATIBLE EXTENDED KEYBOARD (101 KEYS) x12022 ...........•............... .' $69 101 KEY TRACKBALL KEYBOARD Keyboard & mousa in on• X 1 2 0 3 0 . ~ ..$199.95 $99.00. Double your disc storage I : space! ! L--------------- ~ KEYBOARD STORAGE DRAWER C21083 ..~ $84.95 II~ 31/2"x 40 DISK ~ , CAPACITY . ONLY...$6.95 RS232 BREAK OUT BOX WIRE PRINTER STAND C21054 .. ao column ••.•... $29.95 C21056 •• 132 Colunw, .... $34.95 i x111os ............................ s199 Power supply to suit (220W) x11102 .. ............. ,............$199 Addmonally . CPF "s hltenng capabthly helps eliminate troublesome and annoying 1n1erterence . general hash c re_ated by small motors. fluorescent lamps. and the llke thal threaten the performance and shonen equipment life of unprotected electromc componenls SPECIFICATIONS : Electrical rating : 220 -260 volts (AC) SOHz 10 Amp Spike/RF! Protection : 4 500 amps for 20mtsecond pulses Maximum clamping voltage : 275V d1tterent1al mode PRINTER STANDS DELUX PRINTER STAND C21058 ........... ............. $89.00 I computer that profeaaional look. ROD IRVING ELECTRONICS HAVE THERE NEW 116 PAGE 1992 MAIL ORDER CATALOGUE KEYBOARDS CPF CONTINUOUS POWER FILTEA SPIKE ARRESTOR The CPF provides profec11on from dangerous Eilectncal spikes !hat can cai,se anything from obvious damage (like Immed1ate equIpmen1 !allure) to Jess obvious harm that can drasucally shonen a systems hie 1-9 I I Give your . . · DISK BOXES ('1~11ilc, UV EPROM ERASER It will erase up to 9 x 24 pin devices in comp1ete safety, in about 40 minutes (less time for less chips) • Chip drawer has conductive foam pad • Mains powered • High UV intensity at chip surface ensures EPROMs are thoroughly erased Without timer X14.950 ............ .. ....... $99 100 x 5 1/4"" ECLIPSE C16042 ........................ $11-95 40 x 3 1/2"" ECLIPSE C16040 ........................ $8.99 120 x 31 /2" LOCKABLE C16039 ...... .. .. .............. $21.95 100 x 51 /4" LOCKABLE C16020 .......... ·········· ·····$13.95 50 x 5 1/4" LOCKABLE C16025 ......................... $11.95 120 x 5 114" LOCKABLE C16028 ........... : .. .. ......... $19.95 with Timer•••••••• $169 BUDGET Z-NIX BUS IBM JOY STICK rr::~·"<at>"~ ~(/.. Compatible \tith IBM, PC, XT, AT Elegant appearance & durable mechanism Auto return cantering An incredible .•.••..•••...•$24.95 ANTI GLARE SCREEN Relieve eye strain & MINI VACUUM CLEANER . headaches and increase ptoductianwith these anti C21087 .. ~ ···~14.95 glare screens . • 14" screen KEYBOARD COVERS C21089 84 KEY............$4.50 C99990 ••••••••••..••.••.... $39.95 • 12" screen C21088 101 KEY......... $5 .95 C99995 •••••••••.•••...••••• $24.95 Change the way you use • "-,,. your computer $139.00 IBM• CARDS - . . 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•...••••...••.•••.•...•..• $1711 DIAGNOSTIC CARD•••.•.•..•. $795 TTL PRINTER ..................••.. $89 6M AT EX/EXP. ...••.•.•..•.•••.••. $325 FAX CARD ........................... $595 4 PORT SERIAL CARD ••...• $199 2 WAY FDD CONT (360)..... $39 RS/232 SERIAL CARD..•••••• $39 GAMES CARD ...••.••.•..•......••$29 AT S/P/G 2 S/P/G ..........•..... $49 4 WAY FDD CONTROLLER (360-1.44M)••••••..•••.....•..•...•• $129 2 WAY FDD CONTROLLER (360-1.44M)...•.............••..•... $89 CLOCK CARD ....••.....•........ $39 SMART DRIVE ADAPTOR IDE/FDC.......•....................... $49 SMART DRIVE ADAPTOR IDE 1/0 FDC •••••...•.•••............ $89 512K/576K RAM CARD ....... $99 VGA CARD 16 BIT 250K .... $89 VGA CARD 16 BIT 512K••.. $129 VGA CARD 16 BIT (1 MEG),$199 II ntennae Include • 75ohm Balun • PVC power coated aluminium boom • 3 year guarantee • UV realatant plaatlc insulators • Water reaisteant plaatic balun caaing • Support off maat available. VHF Channels 0-11 UHF Channels 28-36 Suitable for prime-good signal reception area. This antenna is used for installation on houses, flats and, because of Installation simplicity, on caravans and boats. 5 ELEMENTS L 15020.....•.• $44.95 ASRIGN~ Included with this antenna is a gutter grip mast and a metres of twin feeder cable. Suitable for good signal reception areas. Ideal for houses, flats and caravans. Horizontal or vertical mounting Is provided. AUDIO PRODUCTS VIDEO/ AUDIO TRANSMITTER A small compact unit that allows transmission of video & audio signals (RF) to any TV sat or VCR within range of 30 metres. Ideal for watching videos In the bedroom or kitchen without having to move the entire VCR or having long extentlon leads running through the house. Can also be used as a transmitter for a video camera. With power on/off switch audio and video leads and supplied with an AC adaptor. A16150 Normally..$95.95 NOW ONLY.....$84.95 L10978......•.. $49.95 ~ AS 25 UV and AS 25/5 UV VHF channels 0-11 UHF Channels 28-36 (AS 25) UHF Channels 36-69 (AS 25/5 Suitable for medium-fringe signal reception areas with good front to back ratio. 18 ELEMENTS L 10972........ $109.95 ~ WIRELESS STEREO TRANSMITTER This wireless stereo audio transm itter allows portable compact disc and casstte players to be used with any FM tuner/radio. Ideal for the car, boat or home HI FI system. Simply play the disc or cassette and tune In the signal on the FM tuner. Can also be used with radio headphones. • Mono or Stereo signals can be received. ANALOGUE WORKHORSE • Fuse and Diode protection •hFE measurements O • 1000 ( By x 10 range) • Mirror scale for more accurate reading. RANGES • DC Voltage: O • .1, 0.5, 2.5, 10, 50, 250, 1 (20kohm/v) • AC Voltage : 0 • 10, 50. 250, 500V, 1000V (8kohmN) DC Currant: 0-0.05, (50uA) 2:5, 25, 250mA • Resistance: 0-2K, 20K, 2M 20M ohm • Load Current: 0-150uA, 15mA, 150mA • Load Voltage:0-3V • Volume Level: •10· + 22dB • + • 62dB • DC Current Amplification Factor: (hFE) 0-1000 ACCURACY • DC Voltage & Current: Within +/-3% f.s • Resistance: Within ::/-3% Of arc. • Battery: 1.5V (um-3) 2pcs. 9V (oo6p) 1 pc • Fuse: o.5A, 50 x 20mm • Diode: 4148 x 2 • C.C: 0.04uff x 50V • Size: 147 x 99 x 57mm • Weight: 400g approximately ooov. L 10970..........$99.45 LOGIC PROBES LOGIC PROBES • Useful for TTL or CMOS hashlgh and low Indicator leds and also with pulse memory. • This Is a very handy tool ANALOGUE / DIGITAL MULTIMETER 22 ELEMENTS VHF Channels 0-11 UHF Channels 28-36 (AS 20) UHF Channels 36-69 (AS 20/5) Suitable for medium signal reception areas with Improved VHF gain. 13 ELEMENTS I 011020 •••••.........$59.95 AS 60 UV ~ O12105........................NOW ONLY $675.00 A16100 .............$69.95 VHF Channels 0-11 UHF Channels 28-39 Suitable for fringe signal reception with Improved front to back ratio and high gain on VHF. L 10974........ $119.95 20 MHz DUAL TRACE OSCILLOSCOPE CTR DISPLAY:• 1so mm rectangular VERTIACAL DEFLECTION: • Deflection Factor: SmV to 20V I Dlv on 12 ranges In 1-2-5 atep with fine control • Bandwidth DC: DC to 20 MHz (-3dB) AC: 10Hz to 20 MHz (-3dB) • Operating modea CH-A, CH-B, DUAL and ADD (ALT/CHOP L202 only) • Chop Frequency: 200 KHz Approx. • Channel aeparation: Bottar than 60dB at 1KHz TIME BASE • Type: Automatic & normal triggered in automatic mode, aweep la obtained without input aignal • Sweep nme: 0.2m Sec to 0.5 Sec/ Div on rangea in 1-2-5 atep with fine control and X-Y. • Magnifier: X5 at all timea. TRIGGERING • Senaltivity lnt: 1 Dlv or more Ext: 1Vp-p or more. • Source: INT, CH-B, LINE or EXT • Triggering Level : Poaitive and Negetive, continuously variable level; Pull for Auto. • Sync: AC, HF Rej, TV (each+ or-) at TV Sync. TV-H (line) and (frame) sync are switched automatically by SWEEP TIME/Div awitch. HORIZONTAL DEFLECTION • Deffectlon factor: 5mV to 20VI Div on 12 rangea in 1-2-5 atep with fine control • Frequency reoponae: DC to MHz (-3dB) • Max Input Voltage: 300V DC+ AC Peak of 600V p-p • X-Y operation: X-Y mode le aelected by SWEEP TIME/ Dlv switch. • Intensity Modulation Z Axle: TTL Level (3Vp-p--SOV) + brigh~ • dark OTHER SPECS: • Weight: 7Kg Approx • Dimenaiona: 162 (H) x 294(W) x352(D)mm. DIGITAL MULTMETER HC-3500T DISPLAY: 3/12 DIGIT BASIC ACCURACY: 0.5%DC DC VOLTAGE: 0-1000V DC CURRENT: 0-20A AC VOLTAGE: 0-750V AC CURRENT: 0-20 A RESISTANCE: 0-20M OHMS TEMPERATURE:-20°C • 1200°c CONTINUITY TEST, DIODE TEST TEMPERATURE CAPACITANCE FREQUENCY, hie TEST, DATA HOLD. O13000 ...was $169.00 now only $149.00 • HC • 505DB 3 1/2 DIGIT • Basic accuracy: 0.5%DC • DC Voltage: 0 • 1000V • DC Currant: 0-10A • AC Voltage: 0 •750V • AC Current: 0. 10A • Resistance: O. 20M ohms • DC AC DMS:-45dB • +50dB • Temperature: -20 °c 1200°c • AC Freq Spread: 50 Hz· 2KHz Continuity Test, Diode Test. O13020............$169.00 PICK UP YOUR FREE 1992 MAIL ORDER CATALOGUE FROM ONE OF OUR STORES! for the hobbles! or serloustechniclan for tracing those hard to find faults on logic boards. 011272 .............. $19.95 LOGIC PULSER • Can be used directly to Inject a signal Into logic circuits without removing IC • Compatll>la with TTL, DTL, RTL, HTL, MOs and CMOS. 01127 4.................$42.95 ~ t== ~I=== QUALITY 3mm LEDS 1-9 11).99 100+ "'"'~"-~ 1-9 10+ 100+ P10516 $2.50 $2.25 $1 .50 BNC CRIMP PLUG 1-9 1~99 100+ P10530 $3.95 s:n5 $3.oo BNC SOLDERLESS TWIST ON PLUG CANNON PLUGS AND SOCKETS 1-9 Z10140(R) S0.15 Z10141(G).. S0.20 Z10143(Y).. $0.20 Z10145(0).. S0.20 10-99 100+ $0.12 $0.18 $0. 18 $0.18 $0.10 $0.15 $0.15 $0.15 QUALITY 5mm LEDS Z10150(R). $0.15 $0.12 $0.1 0 Z10151(G). S0.25 $0.20 $0.18 Z10152(Y) .. $0.25 $0.20 $0.18 ---== -------- FLASHING LEDS RED 5mm 1-9 10+ 210159 $1.10 $1.00 1-9 RED GREEN YELLOW ORANGE - CANNON TYPE 3 PIN CHASSIS FEMALE 1-9 10.99 100+ MOSFET SPECIALS 10+ 100+ 20i 15, 12, 20, 15, 12, 20i 15i 12i 20, 15~ 12, CIC SOCKETS ) ULTRASONIC TRANDUCERS Designed to transmit at 40kHz (L 19990) & recieve at 40kHz (L19991) withup to 20V liP on the transmitter. These units can·t be heard so are ideal for TV remote controls, water level dectectors, burglar alarms, motion . dectectors & information carriers as they can be either pulsed or used in a WIRE WRAP IC SOCKETS Those qualtty 3 level wire wrap sockets are tin plated pho!!phor bronze. P10579 Spin $1 .50 $1.40 P10580 14pin $1.85 $1.70 P10585 16pin $1.95 $1.80 P10587 18pin $1.95 $1.80 P10590 20pin $2.95 $2.75 P1 0592 22pin $2.95 $2.70 P10594 24pin $3.95 $3.50 P10596 28pin $3.95 $3.50 P10598 40pin $4.95 $4.50 Receiver L19991 ••....•$2.95 WOW! FROM $1 .00 COMPUTER CABLES • Six conductor ah lelded computer lntert1ee cable. W12670 • CIC6 6 con. 1-9M 10M+ 100M+ $1.30M $1.10M $1.00M W12672 • CIC9 9 con. 1-9 M 10M+ Those qualtty 3 levol wlro wrlp sockets are tin plated pho!!phor bronze. P10579 Spin $1.50 $1 .40 P10580 14pin $1.85 $1 .70 P10585 16pin $1.95 $1.80 P10587 18pin $ 1.95 $1.80 P1 0590 20pin $2.95 $2.75 P1 0592 22pin $2.95 $2.70 P10594 24pin $3.95 $3.50 P1 0596 28pin $3.95 $3.50 P10598 40pin $4.95 $4.50 100M+ $1.60M $1.50M $1.20M W12674 • CIC12 12 con. 1·9M 10M+ 100M+ 1-9M 10M+ 100M+ $3.50M $3.20M $2. 50M W12678 • CIC25 25 .con. 1-9M 10M+ 100M+ $3.90M $3.40M $3.00M ELECTRET MIC INSERTS With pine for eaey board lnaertlon. C10170 1-9 11).99 100+ $1.20 $1.00 $0.90 10+ 100+ • OE9P Spin plug P12166 $1 .50 $1 .20 $1.00 • DA15P 1Spln plug P12168 $1.50 $1.20 $1.00 • 0825P 25 pin plug P12170 $4.50 $3.95 $3.50 •• DTYPE IDCSOCKETS 1·8 10+ • DEBS 9 pin •ocket 100+ P12167 $1.50 $ 1.20 $1 .00 • DAUS 15 pin ooeket P12169 $1.50 $1 .20 $1.00 P12171 $4.50 $3.95 $3.50 VOLTAGE REGULATORS BARGAINS Deacriptlon 7805UC 78 12UC 7815UC 7905UC 7912UC 7915UC 78LOS 78l12 LM324 555 . 741 1-910+ $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 1-9 $9.50 $10.00 $8.50 $9.50 10+ $8.00 $9.50 $8.00 $8.90 C NICADS ~ Save a fortune on expensive throw away batteries with these quality Nicada and Size AA 450mAH 1-9 10+ $2.95 $2. 75 s1ze c ·12AH $9.95 $9.50 100+ $2.50 $8.95 Slze012 AH $9.95 1·9 10+ 2155 240V 6-15V 1A M12155 ......... $8.95 $7.95 2156 240V 6-1 SV A2 M12156 ........ $13.95 $12.95 $9.50 $8.95 PS2 CONNECTORS ea__) - w M12851 .........$4.95 •. $4.50 6672 240V 15 30.c 1A tapped M166n ....... $ 12.95 $11.95 VGA MONTOR 12VDC FANS 80 X 80 X 25.4mm 12V OC. 1.7 Watt 0.1 4 Amp T12469 •.....•••.•..... $18.95 10+ fans, only s11.g5 FANS Qualtty fans for use In power amps, computer hotspot cooling etc. Anywhoro you notd plenty of air. 240V 4 5/ 8"' T12461..$16.95 115V 4 518'' T12463 .. $16.95 240V 3112"' T12465 .. $16.95 115V 3 112'' T12467 ..$16.95 10+ fan• (mixed) Only $14.95. IDC CENTRONICS 36 WAY PLUG & SOCKET $2.95 TOGGLE SWITCHES ) 2851 240V 12-6V CT 2S0mA • 0B255 15 pin aocket $2.50M $2.20M $1.90M W12676 • CIC16 16 con. 2SJ49 2SJ56 2SK134 2SK176 ) • 1/4"" NUT DRIVER • 3/16"' NUT DRIVER • 3 CLAW PARTS RETRIVER/EXTRACTOR •TWEl,IERS • T10, T15 TORQUE SCREWDRIVER • #1 PHILLIPS SCREWDRIVER • 3/16"' FLAT SCREWDRIVER • IC EXTRACTOR • IC INSERTER, 14-16 PIN re·. • #0 PHlLLIPS SCREWDRIVER • 1/8"" FLAT SCREWDRIVER • VINYL ZIPPER CASE Rechargeral ECONOMY TRANSFORMER $1.95 IDC PLUGS & SOCKETS 1-9 WIRE WRAP IC SOCKETS DB25 CONNECTOR SPECIALS 1-9 10+ P1oaao DE9P $1.00 $0.80 P10885 DE9S $1.00 $0.70 ·P10891 DA15S $1.00 $0.70 P10892 DA15C $1.00 $0.90 P10895 DA15S $1.00 $0.80 P10902 DB25C $1.00 $0.80 P10904 DB25P $1.00 $0.80 P10905 DB25S $1.00 $0.80 continuous wave mode. Transmitter 1-9 10+ L19990 ..•.... $2.95 $1.95 D TYPE IDC PLUGS CANNON TYPE 3 PIN LINE MALE We have a great range of panel metera at great priceal 010500 MU45 0-1m A $9.95 010502 MU45 50/50UA $9.95 010504 MU45 0-100uA $9.95 010533 MU52E 0-5uA $12.95 010538 MU65 0-50uA s1as 010540 MU65 0-1mA $12.95 010550 MU650-100UA$12.95 010560 MU650-20V $12.95 C --~ RECTANGULAR LEDS CANNON TYPE 3 PIN CHASSIS MALE 1-9 11).90 100+ P 10962 $3.50 $2.95 $2.50 CANNON TYPE 3 PIN LINE FEMALE 1-9 111-llO 100+ P10964 $3.95 $3.50 $2.90 ROD IRVING ELECTRONICS HAVE THEIR NEW 116 PAGE 1992 MAIL ORDER CATALOGUE OUT NOWI PICK UP YOUR FREE COPY AT ANY OF OUR STORES! NEW SWITCH BOXES 9 PIN D SWITCH BOXES 2 WAY...-........... $59.95 4 WAY••••............ $69.95 MONITOR & KEYBOARD SWITCH BOXES only $69.50 ADAPTOR DB-SP FEMALE TO HD-15P MALE .X15670 ..••.•.•...•......••...... $14.95 "- MOUSE ADAPTOR DB-9P MINI DIN 9P PLUG X15672 ........................... $14.95 Freq response: 50. 15kHz. Range: over 300 feet in open field. A 10450.......... $24.95 HEATSINK COMPOUND ~ Heatsink compound is applied to the base and mounting atuds of transistora & diodea. II maintains a positive heataink seal that improvea heat transfer from the device to the heatsink, lhua increaaing overall efficiency. H 11800 •• 1 0g ... $2.00 H11810.150g. $29.95 THREE SIREN SOUND GENERATOR UM3561 tY.,C 2 sr l l Vou Features: • Four sounds can be selected. • Typical 3V operation voltage. • RC oscillator with an external resistor Is built In. (mask option.) • A magnetic speaker can be driven by connecting an NPN transistor. • Power on reset. The UM3561 ls a low·cost, low power CMOS LSI designed for use In toy applications. Since the intergrated circuit Includes oscillator and selector circuits, a compact sound module can be constructed with only a few additional components. The UM3561 contains a programmed mask ROM to simulate siren sounds. TYPICAL APPLICATION FOUR SOUND APPLICATION 1. Police Siren 2. Fire Engine Siren. 3. Ambulance Siren. 4. Machine Gun. ( No Connection) VOD Typical application with single rail power supply. PARTS LIST. R1,2,3: Min Res 100k R4: Min Res 4k7 Min Res 150k R5: Min Res 10 R6: RV1: Pot Log 22k Axial 1 uF 63V C1: C2: Axial 22uF 25V Axial 2.2uF 63V C3: C4: Axial 100uF40V CS: Polyester 0.1 uF C6: Polyester 0.2?.uF C7: Axial 2200uF 25V 01,2: 1N400l R2 ■ 10Kn SP:80 0.2W ■f'!"'lcer. I Ideal for private listening. Slimline cabinet for placing under pillow SPECIFICATIONS: Speaker: 2" fullrange Impedance: 8 ohm Cord: 1.5 metres Plug: 3.5mm phone plug Colour: Black CASSETTE SALVAGE/REPAIR KIT Mylar splicing/repair tape. Complete kit with everything needed lo repair damaged cassette tapes and cases Included In each kit are: • Complete cassette parts Including case. • Tape spicing bar and razor blades. A10009................$2.95 1·9 TDA2030 10+ $3.95 $3.50 MINI/MICRO CASSETTE ERASER Erase recordings Instantly from mini and micro·sJzed cassette tapes. Simply pass the tape through the slot In the centre of the magnetic fields In this unit and the tape Is erased. The job Is finished In seconds. • No external power or batteries are required. ........................... $6.95 1.02 I Piro e 0.93 These pins are Ideally suited to the take-off points or flying lead11 from a PCB. The solder Is soldered to the copper track with pin protruding ont he component side of the board. These are made for 1.'D2mm holes. H11618 Pack of 20.....$2.95 H11619 Pack of 100...$6.95 H11620 Pack of 1000.$59.95 ITDA2002 ja WATT CAR RADIO AUDIO I AMPLIFIER ' 1.a $2.95 10+ $2.50 1 1 I L-----------------------------------J Ten colour coded jumper leads. • 450mm long with alligator clips on each end. • Alligator clips Insulated with vinyl boots. • Conductors: 1O x 11/0.18mm W1 2000 ..............$6.95 ol 3 Ground 2 Inverting Input 1 Non lnv.,tlng Input AUDIO ' Hole dja 1 12SC945 NPN 110 50 0.1 20400 TO82 I1·8 $0.35 10+: $0.30 1Above Tranalstor will replace 2SC1815, 2SC2320, etc. TUBES 4 Output ACCESSORIES ~- ,PRIYER TRANSISTORS SPEAKER PORTING 5 Supply Voltage ( VSS , No ConnectJon) (No Cpnnocuon. VDD ) Reco~ded Value: R1 ■ 240K!l TR1: IICS48 It I I VCBO VCEO Jc hFE Package I V V a :2sc2s2s NPN 450 400 10 10 T03P ,1-9: $10.95 10+: $9.95 !Above Tranalator will replace 2SC2555, 2SC3306, 2SC4138 etc. j2SC4242 NPN 450 400 7 10 T03P 11-8: $7.85 10+: $6.85 Above Tranaistor will replace 2SC3038, MJE1007, MJE1008 etc. JUMPER LEADS '-+'--'r-------i'-' \ SEL2 No Conncetlon) --NEW TRANSISTORS -----------7 !SWJICHING TRANSISTORS C12117.•••......... $11.95 t::__:_j ' 1·~ ~ ( : 11 SEL 1 (No Connecdon, , . -- ? TDA2030 A high quality audio amp in a 5-pln To220 package that does not require Insulating washers between the metal tab and heatslnk In single rail supply applications. The amp will operate with single or spilt supplies. The distortion up to 12 W Into 40 ls less than 0.2% typically (less than 5% up to 14W) and up to SW Into an is less than 0.1°k (less than 0.5% up to 9W). SPEAKER TERMINAL PLATE Standard size wall plate for speaker outputs. Each wall plate has dual polarised 2 pin DIN screw terminating sockets for left and right speaker connections. Supplled with all hardware. A16061 •••...•.••••....$6.95 HEAVY DUTY JUMPER LEADS Five colour coded.jumper leads. • 560mm long with alligator clips on each end. • Alligator clips are lnsulalll«.i with vinyl boots • Conductors 5 x 20/ 0.20 Black plastic speaker tubes designed for finishing off breathing or porting outlets on speaker cabinets. Por11ng tubes are also Ideal for finishing off desk and furniture that need holes cut Into the surface for passing telephone, computer and electrical cables through. • R60 Inside Dia: 51mm, Length: 65mm • R89 Inside Dia: 82mm, Length: 33mm ....................................$1.45 ....................................$1 .95 SINGLE P10536 ........................$5.95 ~·¥ : ;; J~ DOUBLE P10538 ........................$6.95 These are good quality SIMM Sockets with metal clips at the ends and not the plastic ones which break. These pins are not gold plated so they are much cheaper.They are suitable for wire wrapping and flt holes of 1mm (0.041n) diameter. Two types are available Slngle•sided and Double-sided ~ DOUBLE SIDED Packet of 20 H11680 .......................$3.95 Packet of 100 H11681 .....................$18.95 Packet of 500 H11682~5.95 SINGLE SIDED Packet of 20 H11690 .......................$3.50 Packet of 100 H11691 ......................$17.95 T ALKBACK POWER SUPP LY Build a multi-station headset intercom This multi-station headset intercom is designed to provide clear communication in high noise environments such as at race tracks and rock concerts. It is compatible with existing commercial systems and features low noise circuitry. By MARQUE CROZMAN Rock concerts are renowned for their excessive noise levels. In some instances, even shouting directly into another person's ear will not get your message across. This is especially a problem for production personnel who constantly have to take directions or issue instructions and be heard the first time. This calls for an intercom system with a difference. Race track mechanics and time 16 SILTCON CHIP keepers are also faced with the same problem - to be heard the first time round without rupturing the other person's ear drums. Similar situations occur in helicopters and light aircraft, on construction sites, and in TV and theatre production where the distance between personnel is often the major problem. Our Talkback Headset Intercom system overcomes these problems by us- ing a padded headphone set with a noise cancelling microphone. This drastically reduces the amount of external noise entering the ears and, by placing the mic close to the mouth, can produce high level audio signals that are also substantially free of noise. Each headset is driven by a substation that can be worn on the belt or placed in some other convenient position. Standard 3-pin XLR microphone cables are used to connect the substations together via loop through connectors - see Fig.1. This means that yo.u can connect them together in a simple daisy-chain configuration, distributed along hundreds of metres of cable. This technique allows hands-free, 2-way communication to all substations in the chain and is much easier than connecting every station back to a central point. Each substation is equipped with a / / POWERED POWERED - - - - - - 12SUBSTATIONS - - - - - - Fig.1: the substations are connected together in daisy-chain fashion via "loop-through" connectors. push-to-call switch that flashes a light and/or a buzzer on all stations, to alert operators who have removed their headsets. A volume control sets the headphone level and a microphone switch allows operators to switch off their microphones when not in use , thereby reducing noise input to the system. The buzzer is optional and can be left out of circuit if not required; eg, if the project is for use in aircraft, in a TV studio or for live theatre. Additionally, by connecting the circulating audio line to the line level input of a small amplifier, all communications can be monitored via an external loudspeaker. The substations are powered by a separate power supply unit that may be inserted anywhere in the chain. Up to 12 substations may be connected to a single supply (see Fig.1) but if further stations need to be added, they can be powered from a second supply. In situations where mains power is not available, the system can be powered from a 12V car battery. The only disadvantage here is that the call function ceases to work. a IN ) The substations & ~e power supply are connected together via 3-pin male & female XLR sockets. These are wired according to the industry standard so that they are compatible with commercial units. To add to its versatility, the Talkback Headset Intercom has been made compatible with two popular commercial systems. These are the American Con- r-;r- a aa OUT IN lN OUT OUT IN OUT /PIWERED --7 / / ~WERED, IN OUT IN a""t#"' IN cert-Com system as used by theatres and production companies around the world; and the Australian-made Jands system. IN r~ ) / / rOUT aa 1N OUT IN OUT - - - - - - - - - - - - 12 SUBSTATIONS Fig.2: by adding a toggle switch & an additional pair of XLR sockets to the power supply, it can be used as a master station to switch between two different substation chains. ]UNE 1992 17 Fig.3 (left): the substation circuitry is based on op amps ICl & IC2. ICla functions as a microphone preamplifier, while IClb, Q2 & Q3 form a small audio amplifier that drives the headphones. IC2b functions as a Schmitt trigger oscillator when the CALL button is pressed & drives Ql to flash a lamp & activate a buzzer. ffi •::::: :::, "' a ~ 3:' ~~+ ,..H· ~ .~; C>z N ,_ ao... I• + > .. I· C, O>- + > ;! -0> C>!i1 Cz . ill N == 0 (.) a: w 1- z 1- w en 0 et w J: ~ > ---YMrll· ~ N N !,?Ni :E"' ~ ~~·I ..,, 3:1 "'> Circuit details _.,,M+ . 0 .., lE ~3: ... "-o 0--' ' 18 SILICON CHIP The main difference between these two systems is that the Jands system uses a male headset socket instead of a female socket and that's the standard we've adopted here. The pin wiring for both sockets is the same. Both the Jands and Concert-Com systems use a master station and a host of substations. In each case, the master station contains the power supply and a substation, and has the ability to switch between substation chains. Although we didn't put a master station together, this could easily be done by combining the power supply and a substation in one case. Chain switching could then be achieved by adding two extra 3-pin XLRs and switching the audio line (pin 3) between them and the existing XLR socket pair. Alternatively, you can use an existing substation and just add extra XLR sockets to the power supply case (there is room on the rear panel to do this). A switch could then be added to the front panel to switch the audio signal between the two pairs of sockets. Fig.2 shows the basic details of this scheme. In most cases, however, this will be unnecessary unless you want to switch between two substation chains. Generally, the scheme shown in Fig. l will be more than adequate. UJ ww 3:'"' ~ > Refer now to Fig.3 for the circuit details. It can be roughly divided into three basic sections: a microphone preamplifier (ICla); a headphone amplifier (IClb, QZ & Q3); and a call detector and lamp/buzzer driver circuit. Voice signals picked up by the headset microphone are coupled to pin 2 of ICla via a lµF capacitor and 560Q resistor. Alternatively, this stage can be fed with line level signals via potentiometer VRl and its associated components. ICla operates as an inverting amplifier with a gain of approximately 400. Its output appears at pin 1 and is coupled via two lOµF electrolytic capacitors to the microphone on/off switch S2. From there, the signal passes via a voltage divider and 0. lµF capacitor to pin 2 of ICZa. Note that the two lOµF capacitors at the output ofICla are wired back to back to form a bipolar capacitor. This blocks pin 1 of ICla from the DC that appears on the audio line when the CALL button is pressed. IC2a is wired as an inverting op ·amp with a gain of 1:0. This stage provides additional boost for signals from ICla and also serves to boost incoming audio signals from other substations. The l00pF capacitor across the l00kQ feedback resistor rolls the response off above 15kHz, as does the 47pF capacitor across ICla. These capacitors eliminate any tendency for the op amps to exhibit highfrequency instability. The audio output signal from IC2a is AC-coupled to volume control VRZ and then fed to the inverting input (pin 6) of op amp stage IClb in the headphone amplifier. IClb's output (pin 7) drives Q2 and Q3 which operate as a complementary class-B output pair. These two transistors are there to boost the out- This is the view inside one of the finished substations. The PC board is secured by sliding it into slots that are cut into the plastic ribs on both sides of the case bottom (see Fig.6). Take care with the wiring to the XLR sockets. put current capability of the op amp and are included in the feedback loop to minimise distortion. In addition, the crossover distortion has been reduced by using D9 & DlO to provide about 1.2V of bias between the bases of the transistors. The 180Q resistor and .0047µF capacitor at the output form a Zobel network which operates in parallel with the headphones to prevent highfrequency instability. Call detector/driver Fig.4: the supply circuit uses a 30VAC transformer, a bridge rectifier & a 2200µF capacitor to feed an LM317 adjustable 3-terminal regulator. The 120n and 2.7k.Q resistors at the output of the LM317 set the supply rail to a nominal +30V. F1 25DmA ICZb is wired as a Schmitt trigger oscillator and functions as a call detector/ driver stage. It is activated for a short time whenever the CALL button (S3) is pressed and drives a 12V lamp r---7 Por,ER I 11 and the optional buzzer via transistor Ql . Let's take a closer look at how this circuit works. Pressing S3 pulls the audio line to +Vcc so that all substations respond to the call signal. When this happens, a lO0µF capacitor (in each substation) charges via a 22kQ resistor and this applies a fixed +15V (ie, ½Vee) bias to pin 5 of ICZb. ICZb now oscillates at a frequency of about lHz, as set by the 47kQ feedback resistor and the l0µF timing capacitor connected between pin 6 and the positive supply rail. Diode DB and the lOkQ resistor in ICZb's feedback network set the duty cycle at IC2b's output (pin 7) to about 5:1. This is because the l0µF timing capacitor discharges only via the 47kQ 05 1N4002 12 * A~ 240VAC I I I +3DV 1200 E • EXTRA SOCKETS If REQUIRED 2200 5DVW 06 1N40D2 10 35VW + POWER + - *FEMALE XLR POWERED LED1 *MALEXLR UNPOWEREO DV .,. TALKBACK POWER SUPPLY ·-~- jl *5EE TEXT OUT JUNE 1992 19 feedback resistor and then quickly discharges via DB and the lOkQ resistor when pin 7 of IC2b swings low. The +30V rail from the supply enters the substation on pin 2 of the 3pin XLR socket. The lOQ resistor acts as a fusible link and D7 protects against reverse polarity connection. The +30V rail, shown on the headset intercom circuit (Fig.3) as V+, drives the CALL lamp and the output stage of the headphone amplifier. Because the LM833 op amps have a maximum supply voltage of 36V, the V+ rail is fed via a 330Q resistor to a 33V zener which provides protection in the event of the supply rail rising. This zener-protected rail is shown as Vee on the intercom circuit. This rail also feeds a voltage divider network consisting of two lOkQ resistors which provides the Vcc/2 rail (nominally +15V) and acts as a bias supply for the op amps. zero tolerance; ie, exactly the value specified). Also shown on the circuit of Fig.4 is power indicator LED 1 and a 2.7kQ resistor feeding it. These components are optional and may be omitted if you use the specified illuminated mains switch. The circuit shows the output connected to two XLR sockets but you may want four sockets, depending on your requirements. The 4-outlet version allows the supply to be placed anywhere in the chain and will power up to a dozen substations. The two powered outlets provide in and out connections. A further two outlets are unpowered to allow the connection of additional substations which are fed from an-• other power supply. These sockets are only wired to pins 1 and 3, to separate the supplies. The 2-outlet version only has one powered and one unpowered outlet. CAPACITOR CODES (10%) Power supply The power supply is shown in Fig.4. It employs a 30VAC transformer, a bridge rectifier and 2200µF capacitor feeding an LM317 adjustable 3-terminal regulator. The 120Q and 2.7kQ resistors at the output of the LM317 set the supply rail to a nominal +30V (actually 29.51Vifall components are 0 0 0 0 0 0 Value 0.1µF .0047µF 220pF 100pF 47pF IEC Code 100n 47n 220p 100p 47p EIA Code 104K 472K 221K 101 K 47K RESISTOR COLOUR CODES 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20 No. Value 4-Band Code (1%) 5-Band Code (1%) 3 1 1 1 820kQ 220kQ 100kQ 56kQ 47kQ 22kQ 10kQ 2.?kQ 1kQ 560Q 470Q 330Q 180Q 120Q 33Q 10Q grey red yellow brown red red yellow brown brown black yellow brown green blue orange brown yellow violet orange brown red red orange brown brown black orange brown red violet red brown brown black red brown green blue brown brown yellow violet brown brown orange orange brown brown brown grey brown brown brown red brown brown orange orange black brown brown black black brown grey red black orange brown red red black orange brown brown black black orange brown green blue black red brown yellow violet black red brown red red black red brown brown black black red brown red violet black brown brown brown black black brown brown green blue black black brow11 yellow violet black black brown orange orange black black brown brown grey black black brown brown red black black brown orange orange black gold brown brown black black gold brown 2 8 1 2 2 1 SILICON CHIP ~ r AC SC04104921 0 Fig.8: full-size etching pattern for the power supply PC board. Fig.6: here's how to modify the plastic case to accept the substation PC board. You will also need to remove several integral pillars before the board will fit. This means that the supply has to be placed at one end of the chain. Furthermore, if more than a dozen stations are to be used, the next power supply has to be connected after the twelfth station - see Fig.1. Construction The Talkback Headset Intercom is housed in a compact plastic case made by Arista. The PC board, coded SC01302921 and measuring 90 x 93mm, is made especially for this case, although other cases could also be used. Fig.5 shows how the parts are installed on the board and how everything fits inside the specified case. Before you start assembly, check the board carefully for breaks and shorts in the tracks. If there are any, they need to be corrected now. Install the wire links first , followed by the PC stakes and the resistors. This done, install the diodes and the transistors but make sure that you orient them correctly. The ICs can now be installed. IC2 can be an LM833 or a TL072 but IC1 does need to be an LM833 if a good signal to noise ratio is to be obtained. Fig,7: this is the full-size etching pattern for the substation PC board. The ceramic and MKT polyester capacitors may be inserted either way round but make sure that the electro1ytic capacitors are correctly oriented. The miniature potentiometer is the last item to be installed. Case assembly Installing the completed board requires some modification to the plastic case. It has several pillars and mounting brackets that need to be removed before the board will fit. Using a Dremel®tool or file, these can be cut out or filed down. Next, slots need to be cut into the strengthening webs to secure the board, as shown in the diagram of Fig.6. The front and back panels can now be drilled. You can use the Dynamark® label as a drilling template for the front panel. The hole for the microphone switch needs to be rectangular and is best done with a file or nibbler. Once drilled, you can mount the two switches and pot (already secured to the board) on the front panel. The 3-pin XLR sockets can be mounted on the rear panel with screws, nuts and lockwashers or with pop rivets. If you are going to install the buzzer, it can be glued to the base of the case, between the XLR sockets. Light duty hook-up wire connects it in parallel to the CALL light. To avoid any problems with back-EMF from the buzzer, a 1N4004 diode needs to be wired across the terminals (see Dl 1 on the circuit, Fig.3). Any miniature 12V buzzer is suitable, provided that it will fit into the restricted space inside the case. That's all we have space for this month. Next month, we shall complete the substation construction and give the full assembly details for the power supply. SC JUNE 1992 21 NOKIA CONSUMER ELECTRONICS m ■ cron ■ c• PHILIPS Arca Australian AMP BKC International CKE Comspec Fox Electronics General Electric Harris Harwin lgnis Intel lntersil Johnson Components Kautt & Bux KG Kitagawa Ind. Kriesler Litton MA/COM Maida Marantz Motorola National Electronics NEC Panasonic Parker Magnetics Philips Pulse Engineering Pye Rank Arena RCA SONY<at> ADELAIDE ROLEC DISTRIBtJTORS (S.A.) PTY. LTD. 5-9 Rundloe Street, Kent Town SA 5067. Ph: (08) 366 0000. Faxstream: (08) 362 9900. ALCORA ELECTRONICS 94 Chandos Street, St. Leonards NSW 2065. Ph: (02) 906 1253. Faxstream: (02) 906 1263. RCD Components Redpoint Samsung Semikron Semtech SFE Technologies SGS-Thomson Sharp Siemens Sony Star Printers UTC Transformers Vitelec Warth Whirlpool ROLEC DISTRIBUTORS NEWCASTLE 1 Vista Parade, Belmont NSW 2280. Ph: (049) 47 0008. Faxstream: (049) 47 7018. ROLEC DISTRIBUTORS HORNSBY Unit 2, 107 Hunter Street, Hornsby NSW 2077. Ph: (02) 482 1944. Faxstream: (02) 482 1309. ROLEC DISTRIBUTORS AUSTRALIA PTY. LTD. 20 Hilly Street, Mortlake NSW 2223. Ph: (02) 743 3144. Faxstream: (02) 736 3732. Telex: AA20186. INFRARED REMOTE CONTROL FOR MODEL RAILROADS, PT.3 In this final article on our new remote control for model railroads, we describe the assembly of the transmitter and receiver boards and the connection of the receiver board to the pulse power board. The remote control transmitter is built into a standard plastic case measuring 68 x 130 x 43mm. This is fitted with a Dynamark adhesive label and the PC board inside measures 88 x 57mm and is coded SC15204922. Before mounting any parts on the transmitter PC board, it should be used as a template to mark out the hole positions for the switches on the front panel. In the centre of each of the nine switch locations is a 1mm hole which marks the drilling centre for each switch. Place the PC board on the underside of the lid and with the copper side facing out (ie, as it will be when finally mounted on the lid). Position it so that the end with the By LEO SIMPSON & JOHN CLARKE 24 SILICON CHIP LEDs just clears integral lid pillars. Align the PC board so that it is centred on the case lid and mark and drill out the corner mounting holes through the case lid. Countersink the holes on the outside of the case lid to suit the 2mm countersunk screws. Now secure the countersunk screws to the lid with a nut and temporarily mount the PC board so that the centre hole positions for each switch location can be drilled out with a 1mm drill. This done, remove the PC board and drill the switch holes out to 3mm. The Dynamark adhesive label can now be affixed to the front panel. Before you do that however, you must install and secure each of the four countersunk screws with a nut and lockwasher. Once the label has been affixed, the switch holes can be reamed out to a diameter of 10mm to Transmitter board assembly board. We used white buttons for the faster, forward and 1 and 2 auxiliary switches; black for the reverse and 3, 4 and 5 auxiliary switches; grey for the slower switch; and red for the stop switch. Now mount the IR LEDs. These are mounted with their leads at full length - don't cut them. They are bent over at 90° close to the top of the PC board. Be careful with the orientation of these LEDs (the anode lead is the longer of the two - see Fig.6). Two 5mm holes need to be drilled at one end of the case, to allow the infrared LEDs to protrude. Finally, the battery snap connector can be soldered with the red lead connecting to the positive (+) point and the black lead to the(-) point. The PC board is secured to the lid using the countersunk screws and is mounted on spacers which comprise the nut and lockwasher already in place, a 6mm spacer and a further nut. A final nut on each screw secures the PC board in place. To make the transmitter case easier to handle, we cut it down by 12mm so that its overall depth, with the lid on, is 30mm. To do a neat job of this you need access to a docking saw, radial arm saw or bandsaw. You could do it by hand with a hacksaw and files but it would be a tedious task. You will also need to fashion a bat- You can start the assembly of the transmitter PC board by installing the resistors and the eight wire links. The links can be straight lengths of 0.6mm tinned copper wire or made from the pigtails left over after the resistors have been installed. We suggest that you use the LK3 and LK4 linking options (for transmitter coding), as shown on the PC board component diagram of Fig, 12. Now insert the transistors and capacitors, taking due care with their orientation. To ensure adequate clearance below the front panel, transistor Ql is mounted close to the PC board while transistor QZ is mounted and its leads bent so that it lies over the top of the z.zn resistor. Similarly, the 220µF capacitor is mounted on its side, flat against the board. The ceramic resonator Xl can be mounted now. The 10 pushbutton switches are mounted hcifd against the PC board with the flat side of each switch facing towards the IR LED end of the PC The transmitter PC board is used as a template for marking out the front panel holes before any of the parts are installed. Bend the leads of the infrared LEDs as shown so that they protrude through matching holes in the end of the case. Fig.12: parts layout for the transmitter PC board. Install each switch with its flat side facing towards the IR LEDs & note the mounting arrangement for the 220µF capacitor. provide clearance for the switch tops. By the way, don't attempt to drill the holes out to this diameter. The chances are that the holes will be more triangular than round and you may very well rip the thin metal of the label. tery holder using some scrap aluminium. When complete, you can clip the battery snap to the battery and screw on the case lid. Receiver assembly The receiver PC board is coded SC15204921 and measures 140 x 98mm. You can begin the assembly of the receiver board by inserting all the PC stakes and the links. Note that links LK1 and LKZ are for coding the The PC board is stood off the lid of the case using two nuts, a lockwasher & a 6mm spacer. A final nut on each screw then holds the board in place. JUNE 1992 25 TO PULSE POWER PCB +12V +12V 6 5 ov 4 3 2, 1 • • • • • • • • Fig.14: outputs 3, 4 & 5 are set up for latched or momentary operation by installing solder bridges on the PC board. You can make them all latched, all momentary or choose a mixture of both. A and B rate inputs of ICZ. They must match the coding used in the transmitter. There is one particularly long link on the board, running from one side of the board to pins 1 & 2 of IC9. It should preferably be insulated. You can either use a length of insulated hookup wire or 0.6mm tinned copper wire fitted with plastic tubing. Next, the ICs can be inserted, taking care with their orientation. The resistors, diodes and zener diodes are mounted next and then the capacitors, transistors, resonator Xl and the trimpots. Finally, LED 6, LED 7 and infrared diode IRDl can be mounted. Be careful with their orientation; the longer lead is the anode lead. These three devices should be mounted with their leads at ffitt.Y~ y --- L 0-, -0,.-::::~.,~~ o o-. Fig.15: here is the full-size etching pattern for the receiver PC board. 26 . SILICON CHIP maximum length. This will allow the LEDs to be bent and clipped into the front panel bezels and the infrared diode to mount flush with its front panel opening. Momentary/latched outputs To avoid more work later on, you should now decide whether you want momentary or latched operation of . the auxiliary outputs 3, 4 and 5 (or a mixture of both). These linking options are done on the track side of the PC board by making solder bridges as shown on Fig.14. Do not solder bridge both the momentary and latched connections on the one output - if you do, it won't work. Case assembly details Last month, we described the temporary installation of the pulse power board and a handheld controller intended to let you check the operation. Now we come to the point when the receiver PC board is mounted in the case and married up to the pulse power board. Below: the receiver PC board is secured to four integral pillars on the base of the case using self-tapping screws. Fig.11 (published last month) shows how this board is then wired to the pulse power board & to other external components. The transmitter case can be cut down to an overall depth of30mm (with the lid on) to make it easier to handle. This job should ideally be done using a docking saw, radial arm saw or handsaw but could also be done using a hacksaw & files. After mounting the receiver board on four integral pillars on the base of the case (next to the transformer), you will need to mount all the front panel hardware, including the Dynamark label. If the front panel has not been supplied pre-drilled, it will require holes and cutouts for the power switch, the meter, clip-in bezels for the LEDs, potentiometer VRl and the IR sensor diode. The meter is supplied with a drilling template for the large cutout required. This cutout can be made by drilling a series of small holes around the perimeter of the marked circle and then knocking out the hole and filing it to a smooth finish. The power switch hole can be made by drilling a large hole and filing it to shape. Now the Dynamark front panel label can be affixed to .the front panel. JUNE 1992 27 ••• A UXILIARY 2 •• •• TRACK F/R OFF 3 4 5 OI L e· ACK The infrared receiver diode (IRDl) should be positioned so that its active surface sits flush with the front panel opening. Take care to ensure that its leads are not shorted by the aluminium front panel label. Drill the holes for all the LED bezels and the potentiometer. The hole for the IRDl sensor is made large enough to allow the sensor to protrude slightly into the panel so that it sits flush with the front surface. The meter requires a new scale to be attached. This should be supplied with the kit but if you are not working from a kit, you should purchase the new meter scale when you obtain the Dynamark front panel. To install the new scale you will need to unclip the meter's front escutcheon and remove the two meter scale screws. Remove the old scale by sliding it under the meter pointer, then attach the new one with the meter scale screws. Once all the components are mounted on the front and rear panels, you can complete the wiring by following Fig.11 , presented on page 84 of last month's issue. We used medium-duty hookup wire for all connections, except for the LED wiring and the 1-6 terminal wiring between the pulse power board and the receiver PC board where we used rainbow cable. Note that LEDs 1-5 each require a lkQ resistor in the cathode (K) leg. These resistor leads should be kept short. Note that all wiring must be kept away from the back of the IRDl infrared detector diode. If any wiring is run near this component, the remote control range will suffer drastically. Testing Once the wiring is complete, check your work carefully before switching Fig.15: full size etching pattern for the transmitter PC board. 28 SILICON CHIP on the power. Set all the trimpots initially to mid setting. Once the power is on, you can check the supply rails with your multimeter. We will assume that you have already checked the voltages on the pulse power board but it won't hurt to run through them again now that all the wiring is finalised . For the receiver PC board, connect your common meter lead to earth and check that there is +7V on pins 12, 13 & 14 of ICl, pin 8 of ICZ, and pin 8 of IC3 . There should also be +12V on pin 7 of ICl and pins 5 & 16 of ICZ. Check that there is +12V on pin 16 of IC3, pin 14 ofIC4, pin 8 ofIC5, pin 14 ofIC6, pin 14 ofIC7 and pin 14 ofIC8. If these measurements are not within about ±10% of the nominal value, switch off the power and check for wiring mistakes. Now checks can be made with the remote control. Pressing any button should light up the acknowledge LED. The faster button should bring the meter reading up while the slower button should bring the meter reading down. The auxiliary LEDs should operate when the relevant auxiliary switch is pressed. They should light only briefly if you have selected momentary operation and should stay on until the next button press if you have selected latched operation. Setting the trimpots The first trimpots to adjust are on the pulse power board. Connect your multimeter across the output terminals of the controller and press the faster switch until the voltage is at maxim1,1m. Adjust VRl for a reading of +12V. Now press the slower switch until the voltage reading is at a minimum. Adjust VRZ for an output of 1.5V or thereabouts. This trim.pot may need further adjustment when you start operating trains. If your locomotives start with a very small voltage across the track, you may want to set VRZ for 0V to stop the locos buzzing or creeping forward very slowly when they are supposed to be stationary. Trimpot VR6 adjusts the full scale calibration of the throttle setting meter. To adjust this, rotate the inertia control VR4 fully anticlockwise and then press the faster switch on the remote control to bring the throttle setting to a maximum. Now adjust VR6 until the meter reads full scale. Telecom would like to help you develop it. Telecom Australia wants to encourage entrepreneurs and inventors working on ideas relevant to telecommunications and related fields in Australia. That's what the Telecom Product Development Fund is all about. Already the Fund has supported the ideas of people from many local companies. Companies like Almos Systems from Perth, Security Domain from Sydney, Mosaic Electronics from Brisbane and Teletech from Melbourne. These were ideas that might otherwise have languished or been lost to other countries. Many of the ideas which have been supported are also adding to Telecom's efficiency and effectiveness and, in some cases, are earning valuable export dollars. Any company or individual looking for an opportunity to get their ideas up and running should contact Telecom soon. Not only is financial help available for viable ideas, but Telecom can also provide support with technical and marketing know-how. If you'd like to know more about the Telecom Product Development Fund, call Telecom's Technical Liaison Office on 008 033 673 or send in the attached coupon. = r---------~-------, Telecom Australia I I I I I I I I I I I I I I Please send me an information package NAME COMPANY A~ru POSTCODE L Send to: Manager Telecom Product Development Fund PO Box 249, Clayton, Victoria 3168 ccoso;sc I -----------------ii.I Australian and O verseas Te!ecommu nica tions C orporati on Limited A. C.N . 051 775 556 TRAIN + + SLOWER FASTER + STOP + + REVERSE FORWARD REMOTE TRAIN CONTROLLER ~ Fig.16: here are the full size artworks for the two front panels for the meter scale. & Note that any change in adjustment of VRl and VR2 on the pulse power PC board will affect this calibration and VR6 will then require re-adjustment. Trimpot VR4 sets the forward/reverse disable threshold. It should be set so that the FIR Off LED comes on when your locos are barely moving forward or have just come to stop. Adjustment is easier when the inertia control (VR4) is set to a minimum. Trimpot VR5 sets the rate of braking. We suggest that you leave this at mid-setting until you have had a chance to run your trains for a while. After that, you will probably want to increase the braking distance as you become more experienced with the remote controller. SC 30 SILICON CHIP A-ONE TEST INSTRUMENTS !OIi~◄ I~ IJ.11] IBENC~~~6L;?Nss;C:U~ENTS POWER SUPPLIES VARIABLE TRANSFORMERS DIGITAL HANDHELD & PORTABLE INSTRUMENTS ANALOG HANDHELD & PORTABLE INSTRUMENTS DIGITAL & ANALOG PANEL METERS IB','11 Escort A-ONE ELECTRONIC KITS & MODULES FUN, LEARN & SAVE $$$$$ OVER 100 KITS TO CHOOSE FROM MANY POPULAR KITS INCLUDE: • POWER SUPPLIES (UP TO 20A) • POWER INVEt-ti t:::RS • AUTOMOTIVE • TEST EQUIPMENTS • BATTERY CHARGERS •ALARMS• LIGHTING• AUDIO• PRE-AMPLIFIERS • POWER AMPLIFIERS (UP TO 500w) • DIGITAL VOICE RECORDER • SYNTHESIZER • PLUS MANY, MANY MORE SM -333 VIDEO/AUDIO SURROUND SOUND PROCESSOR 'lll'>J -_·· • • • ·_: OJ . , ~ •• ',,~:z ,,.,,.,,,,,,, I"".\ \:'' ~ ~,,, $239 SM-333 surround sound processor employs the most updated integrated circuits as its heart. It is also equipped with a IDNR) Dynamic Noise Reductor systems IC made by "National Semiconductor" to particularly filter out the annoying noise thal is commonly found on tapes or CD disks; therefore (DNR) system is suitable for and has outstanding performance on different video types, CD, LD, or Dolby Surround encoding disks and tapes, etc. In addition, there is six low noise operating amplifiers and all in one board design, no other external connections connect to the main board besides the power line, hence that makes the internal noise reduced to its minimum level, as well enabling, SM-333 to produce ultimate live pertormance effect. SPECIFICATIONS & ELECTRICAL CHARACTERISTICS: FREQUENCY RESPONSE : 20Hz-20KHz+/-5dB Surround sound output Voltage : 6.6V(MAX) T.H.D. (Front channel) : 0.05% 20Hz-20KHz A:,;,,,/"£, Vei! T.H.D. (Rear channel) : <0.25% Delay time : 5ms-50ms \;;/'' ¾?" Power : AC240V at 50Hz Input signal voltage : 0.1 V-3.5VIMAX) t Dimensions Front channel output : Wide 360mm,(14.2in.) Depth 122mm,(4.82in.) voltage : 01V-3.5VIMAX) Height 53mm,(2.10in.) Input impedance : 47K ohms > NQ SM -320 120W STEREO POWER AMPLIFIER $219 In order to match with the SURROUND SOUND PROCESSOR, our company has specially designed a 120W Stereo Power Amp. This amplifier not only acts as a perfect partner of Surround Sound Processor and many other audio sources. The special design of all components are soldered on one P.C. Board, therefore; connecting wires are deducted to the least, noise and distortion can also be avoided to the minimum. SPECIFICATIONS & ELECTRICAL CHARACTERISTICS: FREQUENCY RESPONSE : 20Hz-20KHz S/N RATIO : BETTER THAN 70dB LOAD IMPEDANCE TOTAL HARMONIC : 40HM·80HM : LESS THAN 0.1 % POWER CONSUM PTION . 130VA DISTORTION POWER OUTPUT : 60W/4 ohms, 33W/8 ohms per channel DIMENSIONS : 360mm(W)x75mm(H)x220mm(D) INPUTSENSITIVITY 14" X 3" X 8-5/8" MIG .10mV LO : 380mV HI : 640mV MAIL ORDERS WELCOME: CHEQUE, MONEY ORDER, BANKCARD, MASTERCARD, VISA OR AMERICAN EXPRESS. COMPUTER BITS ■ BY PAUL LYNCH A look at hard disc drives Almost everyone who owns a PC has a hard disc drive. Here's how to get the best out of it & protect your valuable data. Everybody tells you that your hard disc is going to crash one day. In fact, some of the things you might do can make this more likely. If you move your computer while the hard disc is spinning, you improve your chances of a crash. You do the same if you're in the habit of switching your computer off and on quickly to reboot it. (If you need to reboot quickly while you're running, press Control-Alt-Delete simultaneously or, if your computer has one, press the Reset button on the box). Discs are also more likely to crash in dirty environments. Keep your pets away from the CPU, especially if they want the warmth and shed hair. And don't leave your computer just inside There are not very many people with the patience and the required large number of floppy disks handy to regularly back up, say, a complete OS/ 2/2 .0 (30Mb) or Windows 3.1 (10Mb) installation. Of course, if you have nothing but kosher software in your machine, you don't need to back up those large installations because you have your legal disks at hand, ready to use in time of trouble. All you need back up are your data files - your spreadsheets, letters, reports, manuscripts and so on. But even if you do this meticulously, you still place a lot of faith in your hard disc. If you buy the wrong one when you buy a computer, you will find yourselfin serious difficulty hours of accumulated seconds and minutes while you wait for your data to jump back and forth between hard disc storage and memory. And, of course, some hard disks do crash, although if you follow the practice of updating your equipment (ie, buying a new computer) every three or four years, this is not very likely to happen to you. Hard disks from leading manufacturers are a great deal more reliable today than the one that crashed on me in 1984. Come to think of it, the manufacturer of that device has since gone out of business. Hard disc controller Your computer can run without a hard disc and even inside the box, the hard disc is a separate device. Accordingly, most hard disc-equipped computers come with a dedicated board - the controller - that plugs into the motherboard. Since almost every PC user today wants a hard disc as well as at least one floppy drive, most hard disc controllers are designed to connect your CPU with all your data drives. They do this through "If you move your computer while the hard disc is protocols known as interfaces. If you change hard drives for any reason and spinning, you improve your chances of a crash. the new device has a different interYou do the same if you're in the habit of switching . face, you'll need a different hard disc your computer off and on quickly to reboot it". controller. The first hard disc interface for most PC users in the not-so-good old days an open window if you live in dusty fairly soon - in most such cases, dif- was named ST506. Back then, we or industrially hostile environments. ficulty based on the fact that the disc thought that all hard drives were miraAnother thing everybody tells you you bought is too small for what you cles and we had nothing to compare about hard disks is that you should wantto put on it. In 1992, think 100Mb them with, so it took some time for us back up your data on them regularly. minimum. to understand that hard disks didn't This is getting harder and harder to Other difficulties can arise if you need to be that slow. Those early units do using the traditional technique (ie, buy a slow hard disc when you plan had slow seek times and were slow in copying the hard disc contents to a to run hard disc-intensive applica- transferring data (seek time is the time set of floppies) because the latest soft- tions. While you won't actually be it takes for the disc head to find the ware takes up so much space. This sitting on your hands much of the track you want). calls for a lot of floppies. time, you can expect to log hours and The ST506 disc type had certain 32 SILICON CHIP TRACK -T CYLINDER _J STOCK SALE!! FANS 80 x.80 x 25mm 240VAC .... $16.84 120 x 120 x 38mm 240VAC $16.92 Fan Finger Guards for 80mm Fans ....................... $1.43 Fan Finger Guards for 120mm Fans .. ................... $2.12 MISCELLANEOUS Fig.1: how a hard disc is constructed. It consists of a number of platters stacked vertically on a spindle to form a cylinder. Four platters are shown here but this can vary according to the manufacturer & the capacity of the drive. other problems. For example, if you needed to move your ST506-equipped computer, you had to type in a special DOS command at your DOS prompt to "park the head". If you didn't do this, the head could bump the disc while you were moving your machine, destroying or scrambling the data at the point of contact. Few of us who moved into PCs in recent years have ever parked a hard disc, since later protocols do that automatically every time you shut down. ST506 hard disks are virtually unobtainable today and if you have an old machine with such a drive, and want to replace it, you will almost certainly find yoµ're choosing from IDE (integrated drive electronics), ESDI (enhanced small device interface) or SCSI (small computer system interface) disks and controllers. All these interfaces offer shorter seek times and faster data transfer. SCSI is generally chosen for the larger hard discs - up to 2 or 3 gigabytes and it comes with the possibility of serious problems for you. Different manufacturers implement different options in the SCSI specification and this means that you may have compatibility problems installing a SCSI device. Make sure that your system is working well before you accept it. IDE disks make up a large part of the 40Mb-200Mb devices that are now the main market for PC hard disc drives. But it seems that ESDI and SCSI offer more opportunities for technical development, which means IDE disks may be a vanishing breed. If you have an old ST506 disc and would like to put more information on it, you may be able to do that simply by changing your controller. In recent years, two ways of encoding binary data on hard disks have built on the original FM recording technique. Modified FM (MFM) doubled the FM data density and run length limited (RLL) has •increased it even further. An RLL controller can change a 20Mb disc into a 30Mb disc at little expense - if the disc is RLL-compatible. To check this, track down the local agent for your disc and get an authoritative opinion about its compatibility. Hard disc structure You may have wondered how it is that a hard disc holds so much more information than high-density floppies. Part of the answer comes from the fact that the typical hard disc is not a single disc at all. It's a set of discs called platters, mounted centrally on a spindle to form a cylinder - see Fig.1. There's space between each pair of platters to allow room for the dedicated head that each platter needs. Each platter is arranged like a floppy disc, in that it has a number of concentric magnetically-surfaced rings called tracks, and each track is di- Circuit Breakers 7.5A- Press To Reset ... .. ....................... $7.25 Mains Power Lead 10A 1.8m long ........................... $4.16 9V Battery Snaps .................. $0.20 2 x AA Battery Holder ............ $0.28 12-Way terminal block 10A ... $1.60 SEMICONDUCTORS 1N4004 Diodes ..................... $0 .07 1N4007 Diodes ..................... $0.1 O 1N4148 Diodes ..................... $0.04 MJ15003 Transistor .............. $6.50 MJ15004 Transistor .............. $6.50 MJ 15024 Transistor .............. $8.60 MJ15025 Transistor .... .. ........ $8.60 MJ13007 Transistor .............. $4.87 MFR571 Transistor ............... $4.27 NE555 IC ........ ... ................... $0.30 TL494 IC ........................... .... $2.83 MC14514 IC .. .... .................... $3.00 MC34063 IC .. .. ...................... $2.98 ALL ITEMS 10 PLUS 10% OFF HYCAL ELECTRONICS Unit 4, 62 Gt. Western Hwy, Parramatta, NSW 2150. Pho11e (02) 633 5477 Fax (02) 891 5640 Credit Cards Welcome JUNE 1992 33 MASSIVE TEST EQUIPMENT SALE The following equipment is surplus to requirements and is now offered for sale. Most prices are negotiable. HEWLETT PACKARD 8064A Realti me Audio Spectrum Analyser. 50Hz-1 0kHz. For specialised vibration & acoustic measurements. As new, $2000. Manuals available from HP. HEWLETT PACKARD 5245L Frequency Counter 50MHz. Plug in converters to 12.4GHz available (not supplied). Clean & operational, $350 - 2 available. Service & operator's manuals supplied. · HEWLETT PACKARD 5253B Frequency Counter Plug In. 500MHz. Clean & operational, $300. Service & operator's manuals supplied. HEWLETT PACKARD 11 036A Probe. Suit 41 0C RF Voltmeter. Clean & operational. $100 HEWLETT PACKARD 53278 Timer/ Counter/DVM. Clean & operational. No manual, $300. AWA U210 and U209 Universal Ca- pacitance Box, 10nF to 10µF. And 1nF to 1µF. $20 each. AWAA412 VHF FM Test Set, clean with manual. $300. AD-YU ELECTRONICS 422A Video & RF Phase Meter, $250 clean. AWA E260 True RMS Voltmeter, clean, operational, with manual. $180. HEWLETT PACKARD 200CDR Wide Range Audio Oscillator. $120 clean. HEWLETT PACKARD 8755A HEWLETT PACKARD 675a Signal Generator/Sweeper 32 MHz. As new $750. Service and operator's manuals supplied. 676A Phase/Amplitude Tracking Detector to suit above - as new $400. Swept Amplitude Analyser Plug-In. Suits HP180/182 Mainframe. $200 clean. WAYNE KERR B224 Universal Bridge. Clean, with manual copy. $450. MARCONI TF2330A Analyser 76KHz. Clean & operational $350. Service/operator manuals supplied. HEWLETT PACKARD 1740A 100MHz Oscilloscope with service & operator's manual , $1250.00 AMRITSU MG54B Signal Generator/Test Set 480MHz FM. Clean & operational $250. DRANETZ 3100 Sampling Network Analyser. Complex Measurements to 2MHz. Incorporates 20-column printer. As new $3500. Service & operator manuals supplied. AMERITEC AM48 Hand-Held Personal Transmission Test Set with service & operator's manual. $1000.00 SEKOMIC SS 100 Single pen rack mount chart recorders. 2<at>$150.00 SIEMENS K2001 Level Tracer. TEKTRONIX 100MHz Oscilloscope. Rack mount, blue screen, clean & 200Hz - 4kHz with manual. Clean and operational. $500.00 operational, no manual, $750. SIEMENS D2008 Level Meter. TEKTRONIX 50MHz Oscilloscope. Clean & operational. $500. 200Hz - 18.6MHz. With manual, clean and operational. $750.00 Please call, write or fax: AV-COMM PTY LTD, PO BOX 225, BALGOWLAH 2093 Tel: (02) 949 7417 Fax:(02) 949 7095 34 SILICON CHIP vided into sectors. If you know how to look into your BIOS, you will find recorded there the disc capacity, the number of heads (and platters), the number of cylinders, and how many sectors there are on each track. The meaning of the word "cylinder" here differs from normal. A hard disc cy 1inder is a vertical stack of tracks in the same position on all platters. No hard disc is ready for use until it has been formatted. The manufacturer supplies the disk already low-level formatted - ie, its tracks and sectors are in place. These can be changed if you wish but it's a task for an experienced operator. Either you or your dealer then supplies the high-level format that lets the disc recognise the information you want to send it. Most disks are high-level formatted using MS-DOS, which tells the disc where it wants the boot sector, the file allocation table and the root directory. During the high-level formatting process, the PC operating system may find blemishes on the surface of the hard disc and will cross them out of the book of the living - they become known as bad sectors. In fact, many hard disks have a small number of bad sectors due to manufacturing faults. If, after some time, your diagnostic software reports that the bad sectors are increasing in number, it's time to seek professional help. You may be heading for a crash. When hard disks were slower some years ago, interleaving tweaks were often used to improve performance. If you adopted a 3:1 interleave, the hard drive head would read only every third sector on each disc rotation. Faster processors and faster disks mean that this early tweak is no longer much of a help. Most hard disks are now supplied with a 1:1 interleave and, usually, that's the way they should stay. Always remember that your computer believes your hard disc is whatever you've told it. You can format it simply as drive C. Equally, you can format it as a whole lot of different drives, using DOS, and there are many reasons to tell your computer there's more than one drive in there. The "extra drives", of course, make no physical change to the disc and they are called, a little confusingly, "logical drives". If you install OS/2 version 2.0, you can set up your computer to boot from either OS/2 or DOS. Obviously, to do this, you need two Speeding Up Your Hard Disc DOS was designed when drives were small and speed not highly regarded. As a result, it packs data onto your hard and floppy discs in a way that uses up the least space but isn't all that quick to unpack when you need it. As a result, every time you use your hard disc, it gets a little slower. If you haven't been using a disc defragmenter, it's likely that you're running much slower than yo\,J have to. This is a funny name - what's defragmented is your files, not your disc. The best-known disc defragmenters come with Norton Utilities and PC Tools, which each cost about $200. They do make your disc retrieve information faster. If you want to do the same thing for free, you can back up everything on your disc to floppies, reformat it, and restore all your files. This can take an astonishing length of time. Here are some more things that you can do: (1). Optimise your buffers: buffers are parts of your memory that store data temporarily during information transfer. MS-DOS and DR DOS allot what their manufacturers think is the best number of buffers for the hardware you have - both softwares can detect your configuration during installation. If you have a large hard disc, increasing the number of buffers can speed your work. You do this by changing CONFIG.SYS. On the other boot sectors and you can't have two sectors on one drive. This is one reason to format your hard disc with at least one logical drive. Your particular software may need special partitioning and extra drives. Its documentation will explain why and how to achieve it. Glass discs The hardware is also changing. The first mass-produced glass discs are expected on the market later this year, replacing the earlier metal platters. Also this year, we could see the first discs which leave the head in constant contact with the platter, eased by a lubricating liquid layer. Since a head crash is what happens when the hand, if you use disc caching (see below), you should minimise the number of buffers, perhaps down to one or two. (2). Weed your directory path: your AUTOEXEC.BAT file contains a line that starts with the word PATH. Organise this so that the programs you use most often are at the start of the list of directories that follows- first your root directory, then DOS, then ... well, what do you use the most? When DOS is looking for the start of any file you ask for, it starts at the beginning of your path, and works along it, directory by directory. It's amazing that it gets through so much work. By reorganising your path, you can reduce the work and time. (3). Add a disc cache: there are two types - hardware and software. The hardware devices are expensive and many do not work much faster than the cheaper software. Disk caching is the best way to speed your hard disc. Microsoft offers its software cache, SMARTDRV.SYS, with MS-DOS 5.0 and Windows - which makes it, in effect, free. PC Tools, mentioned above, includes a cache, as does DR DOS. The best-known standalone software cache is the highly-regarded PCKwik. Software caching takes part of your hard disc's contents and puts it in RAM, which works much faster, usually because it holds onto the data you've accessed most recently. head hits the platter, a design which leaves the head and platter in contact all the time will end the era of the head crash. If you really can't get by without the stuff on your hard disc, and you don't have the time or perhaps the self-discipline to back up to floppies , you can install a second hard disc and back up the data from your original hard drive to it. Most desktop designs can accommodate a second hard disc and there is usually a vacant slot on the motherboard for a second hard disc controller. This makes backup a very simple process - provided your backup disc is at least as large as your primary hard drive. SC Ian J. Truscott's ELECTRONIC WORLD 30 Lacey Street, Croydon, 3136 Phone (03) 723 3344 Fax: (03) 725 9443 Mail & Credit Card Orders Welcome **** NOW ALSO AT COLLINGWOOD •••• ** 200 Smith St (near PO) •• ** Phone: (03) 419 8208 •• We stock an extensive range of semiconductors, FETs & Mosfets, power & zener diodes, SCRs, Triacs, Linear ICs, 74LS/HC & 4000 series IC's, high-intensity LEDs and displays. Accessories inc. pots, trimpots, RF chokes, voltage regulators, relays, fuses, globes & heatsinks, as well as a comprehensive range of many popular switches, knobs, plugs & sockets. We offer a huge range of resistors & capacitors and popular parts at competitive prices. Rechargeable batteries, both regular, tabbed, rapid charge and back-up types are available ex stock. Ring for a price on our sealed lead-acid, video, cellular phone and watch batteries. We now offer a speedy, courier delivered, mail order service. HI-FI & PA SPEAKERS Huge variety of all common hi-fi replacement speakers, crossovers, speaker cloth & grilles. Call for a price on our great range of speakers, microphones, cables, audio leads & adaptors - we'll send you a catalogue. 2-way crossovers (pair) from $9 3-way crossovers (pair) from $16 SWF1212" 100 watt RMS woofer $75 SWF8 8" 60 watt RMS woofer $39 Redford PECC 6.5" 60 watt woofer $38 Redford PECC 12" 160 watt woofer $114 DM40 4" 50 watt RMS midrange $16 DT30 1" 35 watt RMS dome tweeter $11 Ferro Fluid 30 watt (60 max) tweeter $13 Piezo tweeters from $16 Speaker wall mounts from $39 2-way speaker switch boxes $18 3-way speaker switch box (impedance matching) $49 Don't forget our disposals store at Sth. Croydon. There's plenty of hard-to-find parts and help you won't get elsewhere! Phone 723 2699 (ask for Mai) JUNE 1992 35 SERVICEMAN'S LOG From a snack to a 3-course meal! The above gastronomical analogy may appear a trifle strange but it's quite appropriate in the circumstances. What presented itself as a simple snack, turned into a full meal and a severe case of technical indigestion. The device involved was a Samsung 50cm colour TV set, model CB5025J, and the fault was plain for all to see. The antenna socket was broken out of the tuner, which is quite a common one with this particular Korean-made unit. And this same tuner is used in a whole range of other sets: Goldstar, Orion, AWA, NEC, Sharp and Tandy, to name just those I can recall offhand. So, as I implied above, it looked like a snack; particularly as the set was under warranty and it was a simple job to replace the tuner. In these circumstances, I didn't pay a great deal of attention to the owner's comments when he showed me what had happened. Had I done so, I would at least have been better prepared for subsequent events. Our loss is your gain Fracarro's ESVU2. The really low loss VHF/ UHF mixer with areasonable price tag. Peter C. Lacey Services Pty. Ltd. P.O. Box 678 (74Fulton Ad.) Mount Eliza 3930 Tel:03 787 2077 Fax:(03) 787 3460 ACN006893438 36 SILICON CHIP In fact, he had stuffed the socket back in position and secured it with sticky tape and a prayer. And although the broken connection was not restored, there was apparently enough capacitive coupling to provide a picture of some kind, even if it was snowy. And, he added, there wasn't any colour. Well, I didn't take much notice of that last remark; what else could one expect with a signal that weak? So I simply went ahead and fitted a replacement tuner. And, of course, this resulted in a nice bright, snow-free picture; one which anyone would be happy to watch - except for one problem. There was still no colour! Suddenly the owner's, comment took on a lot more meaning. The lack of colour was obviously a separate fault and, had I taken the trouble to question him, I would have learnt that this had been obvious before the tuner socket collapsed. A fair dinkum fault Anyway, that was history. I now had to track down a fair dinkum colour fault. Fishing out the circuit, I concentrated on IC501 (TDA3561A) which performs the decoding functions. I established that the video signal goes in on pin 3 and that, according to the CRO, there was a normal signal at this point. The gating pulse, to admit the 10Hz reference burst, goes in on pin 8 and this was also normal. The next logical check was around the reference oscillator crystal, X501, between pins 25 and 26. And here it seemed that I had struck oil; this time the CRO report was negative - there was no reference oscillator signal. So, was it a faulty crystal? This seemed the most likely cause and, in any case, was simple enough to check. I fished a 4.43MHz crystal out of stock and fitted it. Result - still no colour, even though I now had a reference oscillator signal. First whinge However, this signal was very low in amplitude. And that brings me to the first of several whinges I have about the circuit and the data supplied by Samsung. The circuit and manual are seriously devoid of data of this kind, which meant that I was ·on my own. I took a punt on a signal of about 2V p-p and, in the event, this estimate was pretty well spot on. But right now, I had only a fraction of this value. I woke up when I took a closer look, through the jeweller's loupe, at the minute markings on the crystal I had taken out. The crystal was not marked 4.43MHzbut8.86MHz. Whythisvalue is used I don't know but it appears to be the latest trend. " I didn't have such a crystal, which meant that I had to order one from Samsung, and this put the job back a couple of days. But it arrived fairly promptly and I lost no time in fitting it. And this confirmed my previous estimate of the reference oscillator amplitude; it was almost exactly 2V p-p. But that's all it did- I still had no colour. After some thought, I reasoned that the new crystal, while almost certainly within tolerance, was sufficiently different from the original to prevent it from locking onto the burst signal with the setting used forCV0l, a 22pFtrimmer in series with the crystal. In any case it is good practice, when a new crystal is fitted, to adjust this trimmer so that the reference oscillator is running as close as possible to the burst frequency. This then ensures "test points", I would have been an hour ahead. HATIIIX-ADJ CSl4 Anyway, I went ahead and bridged TSOI A524 SIO these "test points". This should have RS:ZO produced colour in one form or an12K ~~ I other. If the reference oscillator's free~ HATIIIX-AllJ running frequency is sufficiently accurate, it can be an otherwise normal C521 221 0$01 pattern, but with the colour slowly 1N4141 drifting from one hue to another as R521 m tlO the phase of the oscillator drifts, relative to the burst. More usually the error is a good deal greater, producing horizontal colour bars, superimposed on the vertical bars, which also drift in colour as the phase changes. And the greater the degree of error, the more horizontal colour bars. But while that may be all very fine (201 :ol.4111' in theory, it was oflittle practical value in this case. There was still no sign of colour in any form after I bridged pins 23 and 24. So where to from here? As I have already noted, I had checked the sigFig.1: the colour decoding ciFcuitry in the Samsung CB5025J. IC501 nal into the chip at pin 3 and the burst is the colour decoding chip & the crystal is at top left, between pins gating signal at pin 8, and found both 25 & 26. The delay line (DL501) is located directly above the chip. Note the poor qualify of the diagram which makes troubleshooting to be correct. But what about the sigjust that much more difficult. nal out of the chip? This appears at pin 28 and goes to the delay line, DL501. Or that's what should have happened. But there was nothing at pin that the oscillator locks in reliably, and no waveforms. Nor is it always 28. And, in view of all the other tests even on a weak signal. strictly correct and , to make it even I had made, I was forced to conclude The standard procedure for this harder, the printing quality is often so that I had a faulty chip. Fortunately, I adjustment is to first disable the lock- poor that it is literally impossible to had a chip in stock, so I simply fitted ing function between the burst signal read the component values. The cir- it. and the reference oscillator. This lets cuit used to illustrate this article is a And that fixed it? No way - there the reference oscillator run free and typical example. was still no colour and I was looking Try to read the IC component at a brick wall with no ideas left. All I the set's behaviour is then monitored using a standard vertical colour bar number and type number directly could think of was to talk to the maesabove the righthand end of the chip tro at Samsung and hope that he had pattern from a colour bar generator. diagram. The type number inside the some ideas. The reference oscillator is then adjusted to produce the closest approxi- diagram - top left corner - is much The result was a lengthy discusmation to a stable and correct colour clearer but is wrong. The correct des- sion during which we covered the ignation, as noted earlier, is TDA- history, the symptoms and all the display. 3561A, not TDA3562A as shown here. things I had tried. In fact, we thrashed Second whinge This mistake caused me to order the the whole problem about pretty thorWell that's the broad theory. But wrong component on a previous oc- oughly. But it was all to no avail; they how does one unlock this particular casion, resulting in an inconvenient were just as much against the brick delay. (There is a TDA3562A. It is wall as I was. So I was on my own. system? And this brings me to the second of the whinges I have about used in circuits designed to decode I went over the circuit again, both the data supplied. The manual states both SECAM and PAL signals). on paper and on the board, checking But back to the unlocking proce- voltages, resistors and capacitors, that the system may be unlocked by bridging test points 23 and 24 but dure, I eventually worked it out by many for the umteenth time in case I gives no indication as to where, on reverting to basics and doing a lot of had missed something. I drew a com, the board, these test points are lo- circuit tracing. But I wasted over an · plete blank. cated. Nor are they indicated on the hour in the process and that's not funny. And where did I finish up? At Transcendental meditation circuit or anywhere on the board. The system falls down in other ways pins 23 and 24 on the chip. So, if the When I run into a brick wall like too. The circuit carries no voltages manual had said "pins" instead of this, I find that it is often beneficial to ll!1..J 1m ; -- - JUNE 1992 37 SERVICEMAN'S LOG - CTD put the offending device to one side and, as far as it is concerned, go into transcendental meditation mode. And by that I don't mean squatting on the ground and contemplating one's navel. (Physically impossible at my age anyway)! No , I mean tackling a completely different job and banishing the problem completely from one's mind - at least as far as this is possible. And it is surprising how often it works. More to the point it worked this time. Suddenly, when I least expected it, I realised that there was one component I hadn't checked - the chrominance delay line. And I hadn't checked it because it was obvious that it couldn't possibly have any bearing on the problem. For one thing I couldn't recall ever having had any problems with chroma delay lines; luminance delay lines, yes, but not chroma types. In any case, what kind of a fault would create these symptoms? An open circuit could create problems further down the video chain but how could it kill the signal at the IC output pin? Nevertheless, the thought kept nagging away at me and I was grasping at straws. Fortunately, I had a fair stock of these devices on hand, mostly salvaged from scrapped sets, and it was only a few moments work to prove that my theory was wrong. Full colour Only it wasn't wrong. The set came to life in full colour and, of course, there was now a nice clean signal of around 0.5V at pin 28. So, in some mysterious way, the original delay line was loading pin 28 to the point where it was producing virtually zero output. And I use the word mysterious deliberately. No one, including those at Samsung, has yet been able to offer any explanation. The temptation is to assume that the input transducer had developed a short circuit. But, as I understand it, these transducers are piezoelectric devices, presenting a capacitive load to the input signal. How could they develop a short circuit? So the mystery remains. But at least the fault had been found and the job completed. Well, almost completed. I had previously fiddled with the crystal trimmer (CV0l) and so I unlocked the reference oscillator/burst system again and set the crystal up properly. In fact, it was a fair way out, though still locking on a strong signal. And that's pretty well the end of the story. But I can only classify this job as a real "stinker" and I think readers will appreciate why I described it as a snack that turned into three course meal; three faults - two of them nasty ones - where I had expected only one simple one. However, I must add one more thought. A lot of the trauma I experienced was due to the shortcomings of the manual and circuits, as I explained in the story itself. But, in fairness to Samsung, I'm happy to report that they have taken these criticisms - and mine were not the only ones - very much to heart. The latest manuals are a far cry from the ones I have criticised. They are now well printed and contain all the voltages, waveforms and other data that we have come to expect from other manufacturers. Full marks mate! The Panasonic portable PR.OM t,.. 'SN~C.\< -ro ~ 38 SILICON CHIP ~~5 COU'R.~e:. N\E.A\.-~oe My next story is about a Panasonic 35cm colour set, model TC-1401AR. It, too, was still under warranty, being virtually brand new, and having been in the field for only three months. The owner's complaint was, basically, that there was insufficient brightness but he went on to expand on this (and I did listen carefully this time) saying that, in his opinion, the brightness control was not working at all. And he added that the set was fitted with a remote control and that other functions which it controlled, such as contrast, colour and volume, all seemed to work normally. Naturally, I couldn't hazard a guess as to the nature of the problem and simply suggested that he bring it in. When he did, I turned it on while he was there and, yes, it was exactly as he said; no brightness control but all other control functions normal. More to the point, the effect was the same whether the command was via the remote control or the front panel control. I also noticed that the bright- R1142 181< IC1102 CDLOUR31 · BRIGHT30 01110 P-+-+tH-+-¥N_..._-i R1144 12k IC601 VIDEO/CHROMA J188 JUNGLE LINK P--o--o~-018 BRIGHT J45 LIN L__ ---------~-:>--f. 5V 1 Fig.2: this simplified diagram shows the main components in the brightness control circuit of the Panasonic TC-1401AR. Unfortunately, Link J45 is not shown on the circuit and link J188 was hidden on the board. ness was virtually normal, although perhaps just a trifle on the dark side. Whep I finally dug out the manual and opened the set, I went first to IC1102 (MN15142TEAI),amicroprocessor which handles the functional commands from both the front panel and the remote control. In greater detail, the colour saturation control voltage comes out on pin 31 and the brightness control voltage on'pin 30. On checking these voltages, pin 31 showed a varying voltage, from about 1.5V to 6V, depending on the setting of the colour control. But the brightness control voltage sat at a steady 5V, regardless of the brightness control setting. Well, at least these measurements fitted in with the observed symptoms. But why was it happening? After some preliminary checking around the IC, without finding anything obvious, I felt it was most likely an internal IC fault. After all, it was only a single function that had failed. AUSTRALIAN MADE TV TEST EQUIPMENT 10% discount on all test equipment. 15% discount on two or more items. SHORTED TURNS TESTER , Built-in meter to check EHT transformers including split diode type, yokes and drive transformers. $78.00 + $4.00 p&p So I decided it was worth replacing the IC. Granted, I had to order one and there are 42 pins involved, but this job has become pretty much routine these days - one like this taking about 10 minutes. And, more often than not, the IC is the culprit. Unfortunately, it wasn't the culprit this time. Oh well, it was worth a try and a spare IC wouldn't go amiss. I'll use it eventually. My next approach was to track down the source of that fixed 5V on pin 30. Tracing the circuit (see Fig.2) from pin 30, I came first to diode Dl 110, which is shunted with an 18kQ resistor, R1142. And from the pin 30 side of the diode is a 12kQ resistor, Rl 144, to the 5V rail. So the 5V on pin 30 was legitimate enough, except that it was from a relatively high impedance source. Following diode Dl 110 was a 27kQ resistor, Rl 143, after which the circuit ran through a maze of twists and turns to pin 18, marked "Bright", of IC601, which is described as a "video/ chroma jungle" IC. And, fairly obviously, it was the voltage on pin 18 which controlled the brightness. But ANTRIM TOROIDAL TRANSFORMERS HIGH-VOLTAGE PROBE Built-in meter reads positive or nega- .. . tive voltages from 0-50kV. For checking EHT and other HT voltages . . $98.00 + $5.00 p&p DEGAUSSING WAND Strong magnetic field. Double insulated for your safety with momentary switch operation. 240V AC 2.2 amps. As important as a soldering iron! $75.00 + $10.00 p&p REMOTE CONTROL TESTER Designed to test infrared or ultrasonic , control units . Supplied with extension · infrared detector lead. Output is via a LED and piezo speaker. $84.00 + $4.00 p&p ~~ ~ _TUNER REPAIF!_~ --.:?" ~ ' From $19 exchange plus post & pack Cheque, Money Order, Visa, Bankcard or Mastercard 216 Canterbury Rd, Revesby, NSW 2212, Australia. Phone (02) 774 1154 Fax (02) 774 1154 • • • • 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 5854 Fax (02) 476 3231 JUN E 1992 39 TETIA TV TIP AWA video recorder AV11 Symptom: very poor vertical hold on own recordings or EE picture but OK on pre-recorded tapes. Any light to dark transition in picture content shows several white lines paralleling the outline. Cure: C116, a 0-47µF 50V electrolytic capacitor, defective. This capacitor forms a bypass on part of the tuner/IF AGC circuit and the fault the voltage on pin 18 was, not surprisingly, also locked solid at 5V. causes the IF stage to go into oscillation which destroys the vertical sync pulse. The capacitor tests OK, with no leakage and correct capacity at low frequency, but fails at the much higher intermediate frequency. TETIA TV Tip is supplied by the Tasmanian branch of the Electronic Technician's Institute of Australia. Contact Jim Lawler, 16 Adina St, Geilston Bay, 7015. to secure another component to the board. The other way to open a circuit The missing link without cutting a track is to find a At this point, it was clear that I had series component which can be lifted. to separate these two pins before I In this case, there was a small induchad any hope of determining the tor, L1113, shown near pin 30 of source of this voltage. Now, in theory, ICl 102 on the circuit and also close to it should have been easy to break this this point on the board. It took only a circuit. This board carries a number few seconds to lift this. oflinks, designated with a "J" number, This removed the 5V from pin 30 of which make it easy to open a circuit ICl 102 but still left it on pin 18 of for testing. In this case the link was IC601. So the search area had been narrowed to a handful of components: designated J188. diode Dl 110 and resistors R1142, This link would have made things Rl 143 and Rl 144. As already menvery simple, had I been able to find it. But search as I might, I simply could tioned, Rl 144 goes directly to the 5V not locate J188. I did find it eventu- rail and, in effect, feeds pin 30. I asally but only after I had solved the sume that, when functioning norproblem by other means. It was on the mally, pin 30 can pull this value down, edge of the board and hidden under a as required, via R1144. So, with Ll 113 disconnected, I shut layer of Silastic which had been used the set down and proceeded to check these few components individually. And to help isolate them, I lifted R1142. I then checked diode D1110 , which proved to be perfectly OK. The same applied to Rl 142 and Rl 143. This leftR1144. And thi s was the breakthrough . Instead of measuring 12kQ on the meter, it registered a dead short. And I do mean a dead short; it wasn't a few hundred ohms, or even a few ohms - it was zero. ~ i f ~. . . . Now resistors don't -nu~ OWNE:.~'s C.OM?LP..\NT wA.s, go short circuit and so l!,ft...StCAL-L-Y, iHi\T i\-\1;::."RE: WA..-S I began a detailed ex\I\\SUFFIClENT :B'R.\GH,NE'SS amination of the board 40 SILICON CHIP and copper tracks involved. And this emphasised something I hadn't taken much notice of before. In series with the 5V rail feeding Rl 144 was another of the links that I had mentioned earlier, J45 . Strangely enough, this is not shown on the circuit but is shown on the component side of the layout diagram. The copper track in which this is fitted runs parallel with the track in which Rl 144 is fitted. More to the point, R1144 and J45 sit next to each other, with their solder pads side by side. In fact , one pair of pads is joined to provide the necessary connection between the 5V rail and R1144. The two pads at the other end of these components are separate - or at least they should have been. But they weren't. The solder pad at the pin 30 end ofR1144 was -yes you've guessed it - bridged across to the J45 pad alongside it. (The tracks are only 3mm apart). It wasn't simply a sliver of solder but a genuine solid bridge which had flowed between the two pads during the wave soldering process. Little wonder there was no brightness control; pin 30 of ICl 102 was connected directly to the 5V rail. Of course it was easily fixed; a quick touch with the iron and the set was better than new. And I make that point quite deliberately; this fault must have been present when the set was made and had passed through all tests without being deh:icted. It would appear that the sub-brightness control had been set to produce a typical brightness level but no-one had checked to see whether the brightness control was working. As it was, I now had to reset the sub-brightness control (R312 on pin 18 of IC601) to establish an adequate brightness range. So how did it happen? It probably has to do with the way manufacturers check their sets as they come off the assembly lines. As I understand it, most factories now employ a sampling-type final check, with most sets given only a cursory examination to confirm that they are actually working. Only a small a percentage (or sample) are actually given a thorough check out. It's a far cry from the old days in a radio factory but that's the way it now is. Anyway, I had another satisfied customer. SC News Update Dick Smith Electronics_takes over David Reid in NZ Dick Smith Electronics' wholly owned subsidiary in New Zealand, Dick Smith Electronics NZ Ltd, has acquired the operations of David Reid Electronics Ltd, a long-established company with 22 stores throughout New Zealand. The merged operation will use the existing David Reid Electronics administration and warehousing complex in Auckland, and will be headed by Rob Vincent, the General Manager of Dick Smith Electronics NZ Ltd. Dick Smith Electronics Pty Ltd cur~ rently has 65 stores throughout Australia, and the addition of the David Reid stores will take the total in New Zealand to 37. The combined company will have in excess of eleven 'hundred employees and will operate in every major centre in Australia and New Zealand. In addition, authorised distributors operate in smaller centres on both sides of the Tasman. Commenting on the takeover, Jeff Grover, Managing Director of Dick Smith Electronics, said that "an investment of this scale in New Zealand by a major Australian company was indicative of the company's confidence in the long term economic outlook for the region". David Reid Electronics' store in York Street, Sydney is not affected by the -takeover and continues its independent operations. Hardware lock case decided it was claimed to be based on an erroneous interpretation of the law. The judges confused copyright law with patent law and as it stood this would have changed the course of copyright law in Australia in a negative way. The defendants (The Autokey developers) subsequently appealed to the Full Federal Court, resulting in a reversal of the Federal Court's decision. The defendants won and were allowed to continue to manufacture and distribute the Autokey product. In early 1991, Autodesk made the decision to go to the High court to try to reverse the Full Federal Court's decision. On Tuesday 11 February 1992, 10 months after the case was argued before the High Court, a decision was handed down. A unanimous vote of 5 to Oawarded the judgment in Autodesk's favour. This is unique in a High Court hearing and is a major victory for Autodesk and Australian software developers. The distinction between copyright law and patent law was clarified and the Court determined that the defendants had infringed Autodesk's copyright and must accept the consequences. The legal conclusion from this decision is that it is unlawful to reverse engineer a software program (even indirectly) and then produce a product from that reproduction. This case will be quoted for years to come, both in and out of Australia. It gives antipiracy efforts an enormous boost and indicates that the courts believe in protecting software developers' creative endeavours. In 1989, Tony Zammit, the then Managing Director of Autodeck Australia, decided to bring an action against a company which was making a product called "Autokey". The sole purpose of Autokey was to unlock the hardware lock accompanying the Autodesk AutoCAD product. Autokey was sold for $500, while AutoCAD sold for $5200 in Australia. In August 1989, the Australian Federal Court judged that the Autokey product infringed Autodesk's copyright in the AutoCAD program and issued an injunction prohibiting the makers and distributors of Autokey from selling or advertising it. Although this decision was good for Autodesk, Wide screen TV sets introduced Philips has announced the release of two wide screen TV sets with 16:9 format, hifi stereo sound and 100Hz field rates for flicker free viewing. Both sets are fully compatible with existing Australian PAL broadcasts and offer two methods of converting.a standard 4:3 TV transmission to fill the wide 16:9 screen. First, it lets widescreen movies currently being transmitted in letter box format (with black band at top and bottom) fill the screen. Second , conventional 4:3 format broadcasts can be widened to fill the screen (thus losing some of the top and bottom of the picture). This mode can be excellent for sports viewing. The two models both have a field store which allows the picture to be displayed with a 100Hz field rate, giving flicker-free viewing. In addition, the larger model, with an 88cm (diagonal) screen, has picture-in-picture which lets the viewer watch one channel while allowing preview of another via the inbuilt tuners. Both sets will display S-VHS and laser disc programs at higher resolution than conventional PAL sets and Above: Philips' new 66cm widescreen TV set (Model 28ML8916). both have SCART Euro connectors. The larger 88cm will retail at $8799 while the 66cm set will sell for $5499. They are on sale at the larger department stores. SC JUNE 1992 41 Look at what the Mac can do now! By DARREN YATES The Apple Macintosh has taken a giant step forward and can now edit video on screen, using this new system from SuperMac Technology. It can also add special effects, cut and paste video and audio tracks and much more. SuperMac Technology has launched itself into the front line with this very impressive video editing package. Headed by the VideoSpigot digital frame grabber, it's supported by a number of software packages which can make any video source look quite professional. What's more, the speed of the Macintosh/SuperMac combination makes a 386 look positively snail-like by comparison. Thanks to InfoMagic Australia, we recently had the chance to play with .... er, evaluate this exciting new package, by making our own movie from start to finish. The VideoSpigot The first thing to do is to capture some video using a small camcorder and the VideoSpigot system. This system consists of a single slot board with an RCA socket at the back which connects directly into the output of 42 SILICON CHIP Move over Steven Spielberg! Now the facilities of a big studio editing room have been squeezed into the Apple Mac, allowing you to capture video from a camcorder or VCR, edit it to your heart's content and then send it back out as video. the Philips Camcorder we had available. Supporting both PAL and NTSC formats, the VideoSpigot uses its ScreenPlay software package to capture video and uses compression routines to store the data on an ordinary hard disc drive. In fact, you can set the frame rate to anywhere between one and 30 frames per second. ScreenPlay lets you take a look at the current images coming from the camera live, record them and then preview them via a sliding controller which lets you look at any sequence of frames, either forward or backwards, at any speed you wish. Saving the images to disc is as simple as calling up the file window, choosing SAVE AS, typing in the filename and pressing return. Adobe's Premiere Once that's done, it's then into Adobe's Premiere software package where all of the editing can be done. Premiere's construction window allows you to take any number of video clips and, by using special effects, to merge the two together. It can also mix three separate audio tracks. ~ ~ Adobe Premiere allows you to view any frame of a video clip by dragging the control in the bottom left corner of the screen. The impressive effects shown here were created using Adobe Premiere. The sound track capture uses the Macintosh's built in ZZkHz 8-bit digital sound system, which is also synchronised to the video. The construction window is quite logically laid out and is easy to use. What's even more impressive is the array of effects that can be added, from changing the brightness and contrast to changing the sharpness of the image. While you're in the middle of editing your movie, you can select any portion you wish to preview by simply setting two timing barriers with the mouse. Many of the softer effects are produced by what are known as filters. Through these, many of the patterns you see in commercials on TV can be produced quickly and easily by a few clicks of the mouse. You can even give the sound track a delayed echo which can be varied to suit your taste. Taking a few PICTs As if that isn't enough, you can take any frame from a video clip and save it as a PICT file. This allows you to then use Adobe's Photoshop and make even fancier changes. Editing' clips stored in the computer is as simple as opening up the construction w indow. This shot shows two clips to be edited into a movie and the effect used to blend them together. The bottom half of the screen also shows two audio tracks which were added to the movie. Photoshop is another software package similar to Premiere but it deals only with stills. It can do all sorts of fancy effects and is limited only by your imagination. As a quick test, we were able to take JUNE 1992 43 The VideoSpigot system uses a small card which fits into an expansion slot on the back of an Apple Macintosh computer. Any video camera with NTSCorPAL output can be used to capture the images snapshots of some of the SILICON CHIP staff and, using Photoshop, give them a bit of a haircut (more like a scalp removal! ..Ed). Photoshop has the facility of being able to sample the exact colour of a pixel using a colour temperature thermometer. This is done simply by moving the mouse to the desired pixel area and then clicking. With the correct colour selected, you can then take a pencil, brush or bucket and change certain features of that still frame saved from the Premiere software. Again, you can also change the colour, brightness, sharp- ness and many other aspects of the picture. It's an extremely powerful and versatile system. Using the system One of the most impressive points about the Mac system is that it is very fast, making a 386 look slow by comparison. Even on a small 14-inch screen, the display is sharp and clear and we had very little trouble editing clips on this size screen. Adobe Premiere is simple to use and also very intuitive, allowing you to get around the screen quickly. Only on a few occasions was it necessary to VideoSpigot uses its ScreenPlay software package to capture video and uses compression routines to store the data on an ordinary hard disc drive. The resolution of the system is very good. 44 SILICON CHIP consult the comprehensive manual and this was another bonus - the manual actually matched the version of the software exactly, which is a rare feat these days. Well done! The VideoSpigot system supports just about all of the Macintosh computers from the Macintosh II to the new Quadra 900 series. For further information on the SuperMac VideoSpigot frame grabber, Adobe Premier and Photoshop software, contact Tony Crease, Infomagic Australia Pty Ltd, 5 Skyline Place, Frenchs Forest, NSW 2086. Phone (02) 930 3900. SC Adobe Photoshop lets you take any frame from a clip and create various effects. In this frame, styling has been selected for editing. This could include diffusing or using mosaic effects to change the appearance. Siemens E Core Sets Siemens ECones use high qualily N27 siferril malerial, featuring an extremely high flux density and a frequency range of 0-0.1MHz. Ideal for r.ompact power transformers, DC-DC converters, Chokes, Transducers, Interference suppressors. Coil former is glass fibre reinforced thermoplastic flame retardant polyester. Bobbin and cone pair supplied. Cal LF-1270 BARGAIN AT $3.95 *** .47 Farad 5.5V Supercap Pushbutton Thumbwheel Type Interlocking Counter Switch These normally sell for $13-$15 each. Save afortune .. Only catSP-0785 $ 3 •95 ea PC Mount Push button Switch 28 Way Pin Header High qualily push on SPST. Grey/black. Cat HM-3211 Cal SP-0725 $1 ea $1.80 Cal RU-6702 $5.50 $10 LED Display Bargain ~ 7 segmenl red LED display, same as lhosc "' 011r catalogue - No ZD-1803 Common calhode. Conneclion details availaulc on request Normally $3 50 ea Cal ZD-1803 112 1-9 $1. 75 ea price 10-25 $1.20 ea 25-99 $1.00 ea 100+ .70~ ea AYl, JA1C JA,C JA,( JArC J1"..rC JArC JA,C, JA,C ,JAY(,, .IA1l, JAYC, NPN, VCB 80V, IC 4A, HFE 20-80, 40W. Flat pack T0-126 device. Normally about $1 each. Pkt 50 for JA 1( JA,C, JA,C 2N5192 Transistor Bargain Ca!ZT-2100 /'.;,,rC A,(' a Q JA,C, JArC, A·,c, JA·,c, AYC1 A,C, A, C, JA1(,1 JArC, ~~~s JAYCAA EtECTRoNics JAY CAR rncts rn cf:S rnc-,S rncCS rncCS JA iCAA JAYCAR JAY CAR JA'iC~R JAYCAR E:cE CTRONICS EU,CTRONICS E:cl:CTRONICS U.ECTRONICS EcECTHONICS JAY CAR JAY CAR JAY CAR JAYCAR JAYCAH j:i:~ci-fioNics FLFCTRONICS ELECTRONICS ELEC TRONICS El FCTRONICS ELECTRONICS :;;;YCAR JA\ CAf1 JA',CAR JAY CAR JAYCAR ,JAY CAR Ei:rci-rioNics f LfClRONICS FLFCTHONICS El rCTRO'ilC:C, cLFC:TRONICS ELECTRONICS JA': CAR rc i:1:ci-RoNics ,;~ J/\YCAR JAYCAR JA\ CAR ,IAYCAR .IAYCAR ELE:CTRO'ilCS ELECTRCJNICc, ELECTRON/Cc, I I FC:THONICS f-1 H'THONIC:C; c~Fi /,\ CAR JA CAH JA, CAR IAYC/\R .IAYCAR l:Ll:CTRoNics t'LEC TRO'JICS l:LfCTRONIC0 EL f CTT10'11Co I LFClRONIC.~ h rC TRONIC.~ ~~: c:~ f~tc; ;;oNit: ~;; c;~ I.\, c:,,H JA>CAR JA', CAH IAH:1\R .IA ,r:AR c-L;-C: I RC>MCS LLfCfHllNIC'_ELECTRONIC:, I ,fCTi10NIC.~ F I C. THON/I::, -IA, CAH JA,CAH ,JA· CAR ,IAd:AH 1,1·,1 ,,\H L L\.., I f1\.)l\jll.,,) LLC:THOMC!-.. '....~(:THO"JIC(i u-=CTRONI(~) LfCTR()N!CS . f-(;TH()NIC'~ ! I C:lfl()N1C~) J/4,. l l.,>\H f LI\._ I r~1-..:·,n,.,"l JAYCAR f U:.( THUt~1C.<1 JA'-CAH E:LtCTHur.tl,:::, JAY CAR Elf'CTnOrJICS .JA f°CAH 1::U· CTRONICS MIXER r;mo, R E,rnor r1E;mo1 KIT See 1991 Catalogue for full details. Strictly limited quantities. All slock Is In the kit department and your local Jaycar store can order In what you require. A deposit will be required. ,::rno1 R R E;rno, R F;TRQr 8 CHANNEL MIXER EQUIPMENT R E;rno, Rack Kit H crTHO~ R dTRO> n EtTRO• R EiTROO R EiTROt This is the basic mixer. This kil gives you virtually all the electronics. Provided - front panel, VU meters, 11 PCB's, all potentiometers (rotary and slide), knobs, components for PCB's, hook-up wire, elc. All cannon AXR connectors are Included as well. II is Ideal for rack mounl and all that Is necessary is a +/-15V 1A power supply. 11 r;mo• R 1:,TRO' R EiTRO• R EiTRO, R FiTRO• R R LiTRO• R EtTRO, R uTRO' R FiTRV R R EiTRO' R Ef rRO· F,rno· E;rno· A oTRG' F1 EiTRO• R EiTRO' R EiTRO• R EiTRO' R fiTRO• R EfTROt R E(TRO' R E(TRO• R E[TRO• R E/TRO' ,R EiTROt ,R E/TRO• ,R E[TRC,• ,R E(TRO· ,R E,TRO• .11 E(TRO' ,R EITRO' ,R E,TRO' ,R EtTRO• ,R EtTRO' ,R E;TRV• ,R E1TRO" ,R EiTRO' ,R EiTRO' ,R EfTRO' ,R E(TRO ,R E;TROt 1A Etlf _,• ,R E(TRC• ,R E,TRO• ,R E!TRO,R E1 TRO• ,R E1TRO' ,R ElfRC' 1R E~TRO• 1R \R 1R 1.R 1R 1R E(TRO• E;TRO" EiTRO' E:TRQf E:TRQ• E:TROt ,R E:rno, 1R E:rno, ,R FITRO" ,R EITRO• 1R EffRO" ,R EiTRO' ,RE rno, ,R E,TRO' 1R E TROf IR E,rno, 1R ETROf 1R E-TRO' 1R E TAO' IR E'rno, catKJ-6504 Ch ass,s . Was $595 Now $395 Cal EE-5910 Was $99 Now$49 Front Panel Cal EE-5915 SELLOUT J.:0. A.I td l ( J.l.,y ( JA·, ( Al J..l.."rCM J/\'1CAI Jr,~ LAI ,.,41(,AJ ,.,.:.·, l,f,I ./,j ~·1 l t ,.,:. rl At ...,1\,C1\I ,l.l.1CAi JA1CAI ...,A·r ::Al ...-,\·rCAI JA·1 CAf ;, 1 ( :., Cal EE-5965 Now $49 Foldback/Effeds Sends Module t Was$99 Was $175.50 ,Ar Now$90 One of these is used in the 8002, however, more can be easily used in a custom configuration. This unit enables you lo lake buffered foldback from the mixer and also allows you lo mix the effects (such as a digital delay line, reverb, elc) back into the line. Once again, all parts supplied. Cat KJ-6507 Was $37.50 ,lk,CAI .J_.:qC1\l 16 CHANNEL MIXER EQUIPMENT Complete 16 Channel Kit Cal KC-5065 Was $1,399 Now$899 Equaliser/Meter Board cat KC-5067 Was $65 Now $35 Foldback/Effeds Board Cal KC-5068 Was $39 Now$15 Power Supply Cal KC-5069 Was $95 Now$50 Front Panel CAI CAI •CM Chassis ' .~ ,C,;\f Was $145 ,:.., ,Al JA 1 (,1\I Now$70 Now $16.50 ,\f "C .:.r Cat EE-5970 JA1 C/,1 JA rlAl .,....... ( CAT AM-4210 NORMALLY $329 JUNE $299 Save $30 6 INPUT MODEL ;" ),\. (',\! _j/; i ( ,\f ,1A1CAf JA', t_;.Af ,.,Ad'Af ,1A·, (:M 10 INPUT MODEL AUDIO MIXER MONTH /\ I (,/\I .J~-, ( Al J/,,C.AI CAT AM-4202 NORMALLY $169 J,\ { ,\f ;~\n.1\f JUNE$149 IA, C,\f Save $20 ;...,, CAr J,\.(',\, JA,CAI SEE CATALOGUE FOR FULL SPECIFICATIONS JA, (,A/ ,.J,', ,CAf ;, 1 ( 8 INPUT MODEL Af r,,,-:,"lr JA· ...,M ;....,:_.M CAT AM-4208 NORMALLY $249 /•1(',\f /\y('./IJ JUNE$219 ,.,A, ( ·,\f Save $30 /, I CB RADIO MONTH - 20% OFF Super Cougar Deluxe AM I0 cat DC-201 o ; J,\ '(_ t\/ Cal OM-1600 "' ( ,\f Now $23.96 Mirror/Roof Rack Mount Ji,1(_'.M Was $29.95 J!, .:..._ Cal DC-3075 I) \I ~ Now $223.20 { Ai ( ;./ j,\1<./..f Ji', 1 l_./•.f IA d .~,),\' ( ,\f ],\ ,\f Now$7.16 5' Helicoil Whip Was$8.95 ;~;!~2~heeta~~;B$103.20 ·-~ Cal DC-2015 ,-.., 1 ;,f 1<,,( :.1 SWRMeter June is CB month. We are taking 20% off all CB radios and accessories. See our 1992 catalogue. Pages 74 & 75. 20% off everything on these pages. Examples was $279 (.,'q C..1 •"--f ;., _,\I J:,_' ( ;,, Cal DC-2050 Was$17.95 \A E1TRO" ,R E rno, \ RE TAO' 1R E'TRO• ,n E'TRO' 1R E TAO' 1R F'TRO' 1R E TAO' ,R E,TRQ• ,RE TRQ• 1R E'TROt 1 A E-TRO"' ,RE rno, 1.R E,TAO"' 1R E"TRO" ,R E,THQt JATL1;1 .J1\1Cf\l R E/TF101 R R E;mo, ~;rno, r, r;mor .,•\•CA .JA·, CA, ..JA'r LA ,JAYCAR FtH.:IRUt~IC;:; .:A-rCA ,JA{CAH FLl:.LIH(HilCS JAYCA R Er<HOI H FcelROI R ,Jf\ 1 L,H! ,:,. Now $14.36 Of J,\, C ;,f ,JA 11_.Af J,.\,(J,.f .JA ,LAI .Ji1,CM JA,, ..'.\f J,\, ,;/ JA 1 C Af AQUARIUM THERMOMETER Most tropical fish require atemperature of between 23° and 28°C, and ii is critical. This thermometer slicks lo the oulside of your glass tank and has a temperature probe on a lead which sits in the water, on a 1 meter lead and has a suction cap lo hold ii on the glass. A second sensor is inside the thermometer case and with a flick of a switch, you can read either temperature. 1,\ T l ,\f I,\, ( ,\f J.'\1 ( ;,t J,<\11;Af-- J,WC.i\f JA1LAt Includes battery which lasts eighteen months. Thermometer has adigital readout and is supplied with instructions and doublcsided tape. ,R E m o, Cat XC--0128 ,R E,TROt ,R E: TRQt rn dS JAYCAH cLcC { HONICS m es JAYCAR ELECTRONICS rncs JAYCAR ELECTRONICS rncs JAYCAR fl fCTRON ICS mos JAYCAR ELECTRONICS IA,L,AIIA,,,M·- $22.95 JAYCAH JAYCAR ,JAYCAH JAYCAR JAYCAR I r l' I HU,, ICS LFCTRONICS I FCTRONICS LECTRONICS LI-ClHONICS JAYCAR JAYCAR ,IAY(:AH JAYCAR JAYCAH ELEC~RONICS fU:C'110NICS FI Fr:TRONICS FLECTRONICS 1-LE:CI HONIC!:i JAYCAR JAYCAH ,JAY CAR JAY CAR JA'iCAR ',\,<',\f- [L[CTF10N IC$ FLECTHONIC:, fLEClHONIC, FLFCTRONIC½ fl ECTHOcll( ~ .JA', C1\R A, I ,\H IA, I •\H ,;, , l .\H A, l ;,f< 1-1 fr rn0,,,:1·•, f If I I Hl•NII ' : U l, 'Hc)Nll ' ' Lf C 1HONll • • 11 l l 11(':l\ll IA' CAR IA• l'AH 1A, ,\f1 I.\ Ai1 ,A, l AR f LI-.C 1 f1L'N'( ·,.IA' rMi H r( I Hl!Nll ; ,J/\',CAH t Ll:Cl RONll '> J/\YCAR lLf C f HON,(;,, JA, LAH FU "lf10N<C~ IA,c.AH FLI-CTRONICS lLI-.C f F1ll"<ICS f Uc Cl HON1c;: 1:Lf C 1Ht1NICS f If C1RONIC'i JAYCAH JAYCAH JA\ CAH "'' Ct,H IA\ CAF, J,\,t:AI JA', <"'.Af f LH JH()"<IC, ,JA' CAF f Ll:C' HU',IC~ .JA\ CAF I l t Cl liUt,ll S IA1> :Ar FLEC I Hl)NIU,,JA\ CAF t l H I f1l \JICS JAYCAfs ELfr~ t.Ll::.~· ,Lee FLFC" !:LcC !: _!:C !:LfC E .fF ~FC \11L,.::, JA 'fL AH t'..Lt"l, I HU·\IJl...,,J JAY l.,AM t: L t:L, t MVI \II VV JA l \,.,AH t:Lt:::.1..., I MUJ\111...,V JA Yl,AH t:Lt:L, I HUl''ltl...,::, JAY NICS •NICS NICS NICS JAY CAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAYCAR JAYCAR ELECTF10N ICS ELECTRONICS ELECTRON ICS ELECTRONICS JAY CAR JAYCAR JAYCAR JAYCAR E:LECTRONICS ELECTRONICS ELECTRON ICS ELECTRON ICS 1NICS JAYr.A R F I F(":TRr'll\JJrC:: IAVf':AR F I Fr.TRnt\i 1rc:: !AVf':AR l=l ~r.TA(")N Jrc:: JAYCAH JAYCAR JAYCAR JAYCAR cll=C I HOl'.ICS ELECTRO'- ICS LLcCTRO" ICS ELECTRO\ ICS ,_,,....n l:.1-t:L, I !"iUl\1 11...,::, JA I l,AH rLn.... 1 HUI\JIL,,'"') ,JM YL,AH t '- I l, I HUl'llll,~ JA Yl.,AH t:LC.L, I HUl'-. ll,V JI-'\ l l,,'- JAYCAR JAYCAR JAYCAR JAYCAR E_ECTRON ICS ELECTRON ICS ELECTRON ICS ELECTRON ICS JAYCAH JAYCAR JAYCAR JAYCAP FLECTRONICS JAYCAll EccCrnON ICS ELECTRO".ICS JAYCAR ELECTRON ICS ELECTRO"-ICS JAYCAR f-Lf-CTRO'JICS elf CTRON ICS JA·✓ CAR f-1 f-CTRQ,-,ICS £1.Vrti.l-=l i:-1 r r T Ar'l/\.lrC:: IAYr.H~ F FrTR()f\llr~ 11;1.vrl\R t:.. I "-eTQ/"'11,lli''-. lflVl " IIU LI t.J"TQ(l ... ,Jrc: JAYCAR JAYCAR JAYCAR JAYCAR ELEcCTRONICS ELE:CTRO'JICS ELECTRONICS ELECTRONICS i/\Vf"'ll,Q FI l=f'TA(")f\,l(':C:: JAYCJ. lCIHO\ JAYCI 60 Watt: 12 - 240V THERMOSTATIC SWITCH KIT FOR TV Transmitter for VHF VCRs Ref Silicon Chip March 1992 ccrno~ I J-c Ho~ ~g~~g~ _Ecrno~ .Ecrno, _ccmo,, :~g;~g~ Ecrno, Fcrno, _Ecmo, Fcrno, Ecrno, ~ilt;~g~ Inverter Kit CAR RADIATOR FANS Ref: Silicon Chip February 1992 This inverter is ideal for use anywhere where 240V AC power is not available. The Jaycar kit includes an improved and larger version of the transformer specified for the 40W version, which gives an ex Ira 20 watts to around 60 watts. Ideal for fax machines, electric toothbrushes, battery chargers for mobile telephones, Incandescent lamps, etc., etc. The Jaycar kit includes PCB, box, punched and screened front panel and all specified componenls Including the larger transformer. $99 ;-cmo, fCTRO~ " :i:g;::g~ - :~g~~g~ Ecrno, _Ecmo, _ccmoi. =m:g~ _ECTROS _rcrno, cCTRO', JCTRO.\ _ECTPO'\ LCTHU'\ _f:C7RQ~. ECTRO\ -=CTRO" _ccrno, _Ecmo, _ECTRO' _ECTRO' ,ECTRO~ cE-CTROt, ,ECTROt, clCTRO'· _ECTRQ.\ _[CTRO' ,ECTRO\ L[CTRO~ cECTRQr. L=.CTRQ ~, 1..ECTRQ•, ,ECTRO\ cECTROt cECTRO\ , ECTRO\ cECTRO\ LECTROS L~crno, ,::cmo, ,EcTRo, -jCTRO~ ,:,crno,, L1 Dolby Surround Sound Decoder Kit Rei: EA January 1992. Experience cinema sound in your own lounge room. The Dolby "Surround Sound" process increases the sensation of "being there" by producing an effects channel to create surround sounds which a convenllonals stereo system can't produce. Hook lhis simple kit In conjunction with your Hi Fi VCR or stereo TV and lake full advantage of movies recorded with Dolby encoding, Short form kit- includes PCB, and all on board components. Cal. KA-1741 240V Power Relay Kit Cat.KA-1740 U::CTRO\ 1989 Price $24 JUNE PRICE ONLY ,:;::~,::;-/_ v ""0'~ _ LOW COST SINE/ SOUARE WAVE OSCILLATOR KIT Refer EA March 92 This project is an addition lo our range of low cost bench gear and Is relalively slraighllorward to construct. The kit covers the frequency range of around 6Hz lo 70KHz in four ranges with very low distorlion (typically 0.07%). II is based on a Wien bridge circuit, due to its low cost, high pertormance characteristics. The Jaycar kil comes complete with instrument case, front panel lalm' plus the PCB and all spucil ied components. Our kil is also supplied with 1% resistors and lhe ullra-low noise 5534 op amp. Cal KA-1742 $55 SOLAR BATTERY CHARGER KIT (High Power) RefSiliconChipNov91 $10 $34.95 Cat KC-51022 NEW SEMICONDUCTOR PACK BRAND NEW PACK CatZP-8990 $ 10 This quality ABS black plaslic box is ideal for projects for the car, for example, digital lachos, vollmelers, etc. II measures 87(W) x 26(H) x bracket. There is a limited quantity available. Cat HB-5946 Lt....v, r ,u,,.. ,vu v/"'\, '-'" 11 LLLv 111v 1 ,.. 1vu JM I vMn c.Lc..v I nur'IIVV JA YL,AM r--Lt:L, 1 MUNIL,::::, JA YL,J-\M t:Lt:L.1 MUI\IIL.::t ,JA YL,Ah r-l C-L, ELECTRONICS ELECTRON ICS ELEC TR ONICS FLEC TRONI CS JAYCAR JAYCAR JAYCAR J AYCA R 'i.c.J('Q I AV C('.O P C,"'IDO", UCC l i'l V f"'O R ELECTRONICS ELECTRONICS ELf-CTROMCS EU:CTRONICS i:: r i= croor-.urc: JAYCAR JAYCAR JAYCAR J AY C AR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS -== -~ 70(D)mm, of which about 10mm is used for the front perspex panel mounling (which is supplied). Also supplied is the plaslic mounting JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .J AYCAR fLfCll10NICS FL ECTRON ICS ELECTRON ICS Ei.ECTRONICS JAYCAR JAYCAR JA,CAR JA'ICAR JAY('J JAYC/ JAYC; Jt-\'iCr JA\C, J1\'-rC, IAYC., ,JAr'C, .u\·,·c, JA, C , Jf,rL, EXCLUSIVE KIT TO JAYCAR This new kit will handle currents of up lo 2 amps or so, making it suitable for use with solar panels up lo around 25 walls. Panels above 25 walls can be used but the charger will only allow 2A maximum charge to the batteries. This kil will slepdown the voltage lo lhe balleries when the solar panels output Is above 15 volts and stepuo the voltage when there Is less than 12 V available. Kil includes: PCB, potcores, healsink and all specified componenls. This pack contains a minimum of 100 semiconductors and includes IC's, transistors , TTL, CMOS, computer chips, diodes, etc. This run of packs also includes some bonus LEDs and IC sockets. This pack represents an absolute bargain, so grab one while they last. QUALITY CAR ACCESSORY BOX )I\ICS JA'!--.,/"'\, 1 1 JNICS >NICS INICS IMCS *********** Every workshop needs one of these. Includes all the common types ,,.,;,, Include • 1 x 3.5mm - for PC supporls and relays ~_,,,,;;~ ;?' . • 2 x 1.2mm - for PC pins and hook-up wire • 3 x 1mm -for resisotrs, capacilors, etc. 4 • 4 x 0.8mm - for ICs etc. Total -10 drills Cal TD-2400 j:~g; JAvc, JAYC/ studio Twin Fifty stereo Amplifier Kit $299 DRILL PACK JAYCI JA,c1 JA vc1 JAYC1 JAiC, ~49.Su Cat KC-5110 JAYCI ~~~e3'.~1g1~CRcables. 1 Rei Silicon Chip Feb, March, April 1992 FEATURES OF THE TWIN 50 • 50 walls per channel with both channels driven into 8 ohm loads • Very low noise on phone and line level inputs comparable with many OC players • Up to seven stereo program sources can be connected • Tape monitor loop • Separate ullra-low dislorlion slereo headphone amplifier• Stereo/mono switch • lone defeat switch • Straight forward construction. BEGINNER CONSTRUCTORS CAN BUILD THIS AMP- II you can use simple hand tools and a soldering iron you can build lhis project. virtually everylhing is board mounted making conslruclion incredibly simple, allowing you lo complete this project in acouple of nights. PERFORMANCE SPECIFICATION • Power output (one channel) - 4 ohms 80 watts, 8 ohms 55 walls• Power oulpul (bolh channels) - 4 ohms 70 walls, Bohms 47 watts • harmonic dislorlion less than 0.05% 20Hz to 20kHz at rated oulput level for any input or output. See catalogue for full specifications. The new Studio Twin Fifty is housed in a midi-sized case and comes as a complete kit including punched and screened front panel; black anodised knobs, all specified components and high quality pre-tinned prinled circuit boards. j:~g: $99.50 yii:, ~ir~~fis!~~~Ja~ !~~r~~~ ~u;i'!1~ :p~ilfi;;~~~~~~~~s 1 i~il~a~~. HowmanylimeshaveyouwantedtowatchsomethingfromyourVCRonanother TV set located in anolher room of your house? Up until now you had to run along cables through the walls or lhrough the ceiling. Want to fix lhal? Our new transmitter does away with all those cable and simply connects into your VCR, and transmits asignal to your second TV set. THe Jaycar kit is supplied with Jiffy box, front panel labels and the VHF modulator, plus all specified components exceptthe antennaassemblyand $ 3 g. g 5 Rei: EA January 1992 This kit will monitor lhe power drawn from a "maste( power point socket, and automatically switch on a slave socket. It's very versalile because ii can monitor one or several appliances plugged inlo lhe "masle( and switch one or several devices plugged into the "slave". An ideal use for this project would be lo switch on your Hi Fi system. With a four oullel board plugged into the slave socket, turning on your amplifier (in master) will CTROf. L\CTRO\ u:..c~ HO \ L:,·:rno, L-~CTRO\ L[CTRO\ LECTRO\ LECTRO\ cECTRO\ LECTRO, L:cCTRO\ LECTRO ' LcCTRO\ LECTRO' L~CTRG 1· LcCTROr, LECTRO' LECTROt, LECTRO~ LECTRO, LECTRO, LECrno, L,CTRO\ LECTRO, LECTRO, LECTRO, LECTROS $ 3 7.95 '--;::===================: ' , crno, 1-crno, Fcrno, EC RO\ _cCTRO\ ; crno~ _Ecrnm. . ECTRO~ 90 ' ECl Ref Silicon Chip March 92 Has the thermostat failed on your electric radiator fan? our electronic thermostat can replace It and be adjusted to switch on at atemperature to suit your particular vehicle. The switch will ensure that your fan cuts in and out only as required so that your engine operates al the correct temperature for peak efficiency. The Jaycar kil is supplied with diecast aluminum box, PCB and all specified components except for the sender unit (which is available from K-Marl). Cat KC-5115 ·~ -,.;..,e~ :f~;:g~ _l crno~ :~g:~g~ JAYCI JAYCI JAYC/ JAYCI ELEGTRONICS ELE'CTRONICS ELECTRONICS ELEcCTRON ICS JAYCAR JAYGAH JAYCAR JAYCAR .,/1'rC1 -iAYC1 JArC, J/n(;, JA,(, JA1C1 ,A,c; JATC.,1 J;\1{,. JA,,; IA r Ci: JArC, JA',C / JA)Ci JArC/ J1\rC: JAYCi JA1Cf JAYCi JA\C/ JA\Ci 1,wc: JA\(; lA'rC/ JAYC! IAYCi JAYC/ IAYCi IAYCI IAYCi IAYC/ MUT\IIV,") JMT VMM rL r v I r1U!\IIL,,:> JI-\ r VMn lLCV 1 nui\111....,.:, JAYCI- FLECTRONICS f-Lf-CTRONICS ,-LfCTRON ICS !'Lf-CTRONICS JAY CAR JAYCAR JAYCAR JAYCAR dECRO~ICS E Ll ClHOMCS !'Li CTROMCS ELECTRONICS ll\ V r .O.P i::1 crn=lrtr\l!C.C:.~11.0 .CJ .:.ClLJrtt,JJf"(;; 111.Yf"'/IC i=:1 Cf"TRf"'\r-.11rc: 1.0.vr.o.A ~1 i=-rTRC'I/\UCC:.. IAVf".AR Lo:! JAY CAR JAYCAR JAYCAR JAYCAFi ELECTRONICSJAYCI ELECTRONICS JAYC/ EU:CfRONICSJAYCt t'LfCTRO Nrcs IAYC, ~--r T R:('l"l! f"' C: 11\VrAA ~ I C/"'TCf""\t,.11rc: ,.~vr-r t.LC:l, I HUNll,;:, JI-\Yl,AH C:Lt:l, 1 t,Vi\jll...,.;) JA fi..,AH" t.Lcl, i Hv~11...,;:, JA 11...,,U,H t.lt:l, t Hu,--...n_;::, ,JA 11...,AH t.LU., I Hur,m.,::, JA I l,AH t.LU,., 1 liUNll,0 JA) l,AH t..Lt:.'-.., l 11UNll...,V Jl-'lll...,,"\h t.Lt.l..., I HVNIV'? Ur'IT\Jf"\n CLC\., I nu111c~ f Lt Cl HONIC::- JA, CAR FLFl,TRvNIC" JA'1CAh fLEe, TRONl(c, .'A', CAR clcCTRO"JICS JA ,CAR FLECTROMCS JA\ CAR clf:'CTHONIC'1 JA,LAR Ht CTf-lJ'llC" 'A, CAR Elf CTRONIC,', JA, CAR r LECTRONICS fLECTROMC~ Fl fCTRONIC~ ELECTRONIC$ JA", CAR JA\LAR JA·, CAR J,:,, CAR ELECTROr-.lC$ fLEC1RO"JIC::, ELEC TROMCS ELECTRONICS JA\CAR JArGAR JA\C~R IA>CAR ELECTRONICS ELFCTRONIC::, FLECTRONIC::, ELFCTRO'-ICS JAY CAR JA>GAR JA, CAR JAYGAR f LECTRONICS FU-CTRONICS E~f CTRONICS Flf CTRONICS JAYCAR JA,CAR JA\ CAR IA, CAR ELECTRO"JICS ELECTRONICS ELECTRONICS ELFCTRONICS JAYCAR JAYCAH JAYCAR JA', CAR ELECTRONIC::, ELECTRONICS fLFCTRONICS FI FCTRONICS JAY CAR JAYCAR JAYCAR JAYCAR ELECTROt11c~ ELECTROtllCE ELECTROtllCE ELECTROtllCE ELE 'TRt'f\JIC<, .l.:..T(AR F F-1,Tfi()f\Jlt:S 'A,rO.R FI Ff'TPC'!Nl\.<..,. 'A,f'AR r1 F,-.TROl"\il\C.. IA\r.AR FI FITRl•I\JlrS IA'rl,.'.l,R FI FITrtONII~ IA1C':AR FI F(':TRONlf'S .JAl\.AR F' FC:TRONIC:S JAYCAR ELECTAQtllC:: F Lf '- ~~~~ Professional Horn and Driver ROSS/ -~~~ Motorola cu-c 1155/6 • LrC 'LlC ':Ltc ,LE, This speaker incorporates a CD horn (constant directivity)which is made by the American sound company- 'LE -Le LEG --~LLEEcc cEC ,LEc Lt'C -LEG Le · 1..r < LE[ _L~C ~~f~ L,C Lf-C lfG . ,Fr. Heatsink This month 10 for L[C' LEC :LEG 1--- ------------- 0_64 REF. ",_,,,,, l j__ '#=,___ ! 6 s1 REF- ~ __i25 ; .--I ~ Lf r LE( LtC LEC LEC LEL 0 A~ , , 25 ~ 1,46°.51 _- , ': = -- _ g~~ ~~lg some months now, as we've been I t' th 'JUNK' to go .in accumu a ing e them. Each bag contains approximately3kg of assorted I t , d' Th' I e ec ronic goo 1es. IS run a so includes its own bag of semiconductors. g~~ ~~~g~ CAR CAR CAR CAR Unfortunately, due to massive weight, P & P is normal rates plus $5 _i L___ 2oi32 J ~-~d- ~:~2 j $89.95 MOTOROLA 400 WATT CMPRESSION DRIVER REPLACEMENT ., • KSN 114 ~~~m~r Jaycar will purchase your surplus stocks of components and equipment. We are continually on the lookout for sources of prime quality merchandise. Call Mark Harris or Bruce Routley now ,02, 743 s222 A di reel burnout proof driver for all standard 1"' 18 UNEF thread horns. As used in the above horn driver combinalin, Stop paying for all !hose expensive diaphragm replacements. TH is one is guaranteed lo last 3 years. Power handling 400 watts rms. Cat CT-1922 US ED EPROMS! $45 Portasol Portable Gas Solderina Iron New generation soldering iron. Why bother wilh rechargeable balleries or chargers any more. THe Portasol needs no cords or gas batteries. All you need Is acan of Ronson type Butane cigarette lighter gas. A full lank will last aboul an hour, and ii refills in seconds. Cal TS-1420 • $39 95 Cal ZZ-8500 27512 Cat ZZ-8501 2716 Cat ZZ-8502 $2. 95 (new price $9.95) $4.50 (new price $14.95) $2.95 (new price $9.95) 2708 Cat ZZ-8503 62C64 RAM Cat ZZ-8504 $1.00 $1.50 (new price $15) PUSHBUTTON SWITCH BARGAIN lt=l Lf L · :LEV ,.cc. : Lf ( - lfC' LEC' Lt'.(' u-c Our suppliers senl us the incorrect switch recently, so we need to clear them out and il's your gain. Stock up now. It's a push on momentary, black body, red actuator, 125V 1A rating. Cal SP--0705 HIGH QUALITY IBM Normal price about $1.75 COMPUTER LEADS Bargain price .50~ ea We've made ascoop purchase of IBM brand computer leads, These are high quality leads, The D25M lo D25M has chrome plated backshells and thumbscrews and high quality Hitachi soil, flexible cable. The D25 lo Cenlronics has achrome plated backshell for lhe D25 and an Amphenol Cenlronics plug, again with high quality Hitachi flexible, soft cable. 10+ .45~ / 100+ .30~ RS232 Break out box LErl Lf C' LF !FCl I f(l LEGI cfCl 1.ECl trr 1 Lr Cl LEC' I f-rl LEC' A simple way of checking and monitoring 25 pin D series (RS232) inputs, oulpuls and connecting cables. Connects in line between computer and peripheral and has 12 signal powered LEDs lo indicate which lines are in use, as well as 24 switches and jumper leads to allow you to break out circuits or reconfigure and patch oul of all 24 active lines. Other suppliers sell these tor up lo $99.95. You won't pay anything like lhal from Jaycar. Cat XC-5085 Only $69.95 Brand new addition lo our range of ballcries. Compare our price wilh olher suppliers ca,sB-2462 LE-cr $12.95 ea ~ - - - - - - -- - ~ 24 Pins connected. Length 1.4 ml Cal PL-0879 cU·CTRONICS JA\CAR f LFCTRO"JICS IA, CAR ELECTRONICS JAr CAR f LECTRONICS IA, CAR ELECTRONICS JA\CAR $23.95 SCOPE PROGRAMMABLE HOUSE ALARM BOARD See catalogue for lull details. (No box supplied) Sells for $199.50 wilh box. • 6 sectors plus 6 x 24 hour sectors • No programming required tor normal operation. Includes PC board wilh keypad allached. Cal LA-5182 catalogue price $129.50 May special $ 79.50 save $50 .________________ LFCl. ._ _ _ _ _ _ _ _11111_111___________________1111 LtcClHUNICS JAYCAR LECTRONICS JA,CAH LtCTROMCS JA, CAH LcCTRONICS JA, CAR LfCl RONICS JArCAR $23.95 D25M to Centronics .______,,.......;.::=;::::;::~.- 4AhD Size NiCad t~~; LEC' D25M to D25M 9 Pins connected (I hat's all you require). Length 2.8 ml Cal PL-0875 fLECTRONICS fl I CTROMCS tCTRONICS F-U CTRONICS ELECTRONICS fl JAYGAR JI,, CAR JA ,CAR JAY AR JA, CAH FLECTRONICS fLfCTRO'JICS f l f CTR<l',1( tl t CTHO'JICS f Ll( TRO"JICS t F,C:lRONICS JAtCAR ELECTRQNICS.JA'tCAREil.CI.RONlC~ tAYCAH t If(' IBONIC 1A\CAR C,\R IA, CAh IAYCAR ,,\, CAR Jt" [R~[M]<at>'u'~ [K{~W~C-\<at> 'D'<at> <at>O:DO'u' lnlelligenl remote keypad lo arm/disarm and program lhe S""lem. 7 segment readout, 1" use of use up lo 3 per alarm. Cal LA-5183 Special "r·ce 1 CAR EL~cT CAR EL~cr CAR EL•cT g:~ ~~tg~ cAn ELtcr g~: mg; CAR EL~cr ••~M m;;i-----..- ~...---, ELtCT Elter EL~CT ELitCT EL~CT ELifCT ELifCT ELoCT ELt,_cr ELf':CT EL~C1 EUtCT ELfiCT EUi:CT c:~ mg; CAR ELfiCT CAR ELfiCl CAR ELE'Cl CAR ELitCl CAR ELitCl CAR ELitCl CAR ELitCl CAR ELitCl CAR ELitCl CAR ELitCl CAR ELitC7 CAR Elit.Cl CAR ELf:Cl CAR fll';Cl CAR ELEJ:Cl CAR Elflcc, CAR ELfcC CAR ELfccCAR ELfcc• CAR ELEJ:C CAR ELE;c CAR ELl:!:C' '.:AR ELE'Cl '.:AR ELEiCl '.:AR ELE:C7 '.:AR ELE'C' .::AR ELF:C' '.:AR ELF;c::;AR ELE:C::;AR EU~C :::AR ELE:C' ::;AR ELE:C' ::;AR ELE,c::;AR ELE'C' :::AR ELE;c· CAR ELEiC' CAR ELl'EC' CAR EL8,C' CAR ELE:c CAR ELE:c CAR CAR ELE;c· ELE.'c , CAR ELF:c CAR ELEcc· CAR ELfcc• CAR ELEcc cAR ELE:c g:~ ~t:g ., g:: ~tig ELEl:C ..CAR CAR ELEl:C ■------------------ ELFCTRONICS JAYCAR ELECTRONICS .AYCAR f LEC TRO'JICS IA\ CAR ELFCTRONICS ,AYCAR E, cl THL ·MC' ,A ,CAR ELE-CTRONICS ,AYCAR f L[ LI Hl JNl[S AYCAR ELECTRONICS JAY CAR f Lf l THUNICS JA\ CAH !-LlC 1RONICS JAYCAH '•\, c AS r r r I fJOMCS 10.Y _____ .., $49.95 each CARtLccr CAR CAR CAR CAR CAR CAR CAR CAR CAR CAR CAR CAR CAR ~AR These turned up in a recent surplus slack buy. save a fortune over new prices. Masi are nol erased. We will guarantee these lo be able lo be programmed, and any returned laully will be replaced, bul only up lo 2 weeks afler purchase - keep your sales docket. 27256 . CAH F L~cr $14.95 CalXB-9000 ELEcr Et Ecr FI tcr EL~cT CAR Elf er CAR EL~cr --------- Lf C -u-c $5. 95 CAH cLlcr g:: ~~lg~ CAR E'Ucr CAR Elter CAn cucr CAR rncT CAR Eller CAR wcr CAR EL\cr CAR EL\cr CAR cLEcT We haven't had these available for Normally $1.20 each 1/&i, U, Bargain Bags Back Again.• I We're overstocked, so don't miss this bargain. Cat HH-8503 ROSS. This horn Is extremely well known and sells throughout the world inspeakersthalselltorover$1,700 pair. ThedriverisaMotorola Powerline Piezo which simply screws into the horn. The speaker offers smooth wide angle coverage with oplimumdriver loading, Frequency response 1.8kHz-20kHz Power handling 400W rms Warranty 3 years CalCT-1920 --------------. TO-220 Clip On ELECTRONICS JAYCAR ELECTRONICS JAYCAR ELECTRONICS ,JAYCAR ELECTRONICS JAYCAR ELcCTRONICSIJAYCAR ~ ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAYCAR JAYCAR JAY CAR JAYCAR JAY CAR ELECTHONl1c: ELECTRON~C: ELECTRON IC: ELECTRONl1c: ELECTRON IC: ,..., 1vv JMYVAH t:.Lt::L. 1N.UI\IIL,~ JAYL,AH t.Lt:i.,; I HUNIL.:.:, uAYCAH 1::Ll::.C I HUNICS JAYCAH 1::L~t: I HU"JICS JA·r L...,H Llt:C I HUNIC!:i JA(CAH t:LtCl HUNIC.,b Jr\'rl,MH bl t-- L, f HUML~ JAYl,AH l::Lt:.L ! HUN1V·· ..,An ICS !CS !CS ICS ICS JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTROMCS ELECTRONICS JAYCAR JAYCAR JAYCAR JAY CAR JAY CAR E'I FCTRONICS Elf-CTRONICS E'LECTRONICS f:LlCTRON ICS ELECTRONICS ,AYCAR ,,AYCAR JAYCAR JAY CAR JAYCAR ELfCTRONICS ELECTRONICS Elf-CTRONICS ELECTRONICS ELEC rRONICS JAYCAR JAYCAR JAYCAR JAYCAR JAY CAR ELE:C TR ONICS f LECTrlONICS ELECTRO'<ICS ELECTRONICS ELECTRO"-:ICS JAYCAR ,JAYCAH JAYCAH J,\YCAR JAYCAR ELECTRO!',ICS lLF crnoMCS ELECTRO',ICS cLECTROMCS f LECTROI\ICS JAYCAR JAYCAR JAYCAH JAYCAR JAYCAR E:LrCTRONICS elf CTRONICS f LECTRONJCS F ,E'CTRO\IC~ H f-CTRO\ICS JAYCAR JA {CAI, JA<CAR JA', C',R A', CAH ELfCH101\ICS Elf C I HONIC,, ELE:CTRQNICS Elf CTRO"IICS E, r C rncN ICS JAYCAH JAYCA!, JAYCAR JA', CAR JA'- CAR lLE:Cll10NICS !'LE'CTRO"IICS E:LEC1RO'i1CS rLE'CTRONICS fLECTROMCS ,,AYC, J/\YC, JAYC JAYC JAYC, Clg~~g~ RON;r-::::::--:~-===~=~ :::-:::--:::;;;;;;;;::::;::;;;;::::::;;:;;:;;;:::;:;;:::::::, VIDEO SWITCHER KIT FOR ..,..,...,....,..,_ .,.....,,AIIIII....,,...,.. 3:~g ICS .JAYrA~ !=I i=rn;inr-.ur~ Jti.Vr-AA !=I i=rTA()t..llr~ I AVl:AA i:: 1 ~TTAf"'H\,lr~ IAVrllA !=! i=r~RnNll:S iAYr:.4R FI F-r:TR()\11r.s. AY\.AR.F.lFGTRONl(;S .J~'r("'";,-\R Ft F-l,TR0~1ct; ,JA'r'CAn EU:.CTRO'\liCS JAYC JA1C, ...i~.ii-~lilii g;~g~ CTRO"cTRO"crno" c1 RO"crnoN :crno" :g;=gN crnoN crnoN cmoN g=g~ CTR01' g;:g~ cmo" ·g=g~ CTRO"CTRO"CTRO"CTRO"_crnor-. g:g~ crnoi CTRO" :g;~g~ ·c rno" cmo, :cTRo, \g;:g~ :crno~ :cmo, \g~g~ ,cTRo, ,crno, \g;~g'. :crno, ,C TRO' :CTROf :cmoi ,cTRo, :CTRO,, :cmo, :crno, :crno, ,crnm :crnm cCTRm ,crno, ,cmo, ,CTRO' 'CTRO' :crno· :crno• :CTRO' 'CTRO' 'CTROf :CTRO~ :crnoi :crnm :CTRm :CTROI :CTRm :crno, 'CTRO, :CTRO' ccmo, :cmo, :~~g CAMCORDERS & VCRS ~ CIRCUIT BOOKS Rei SC May 92 Four fabulous new books published by Micro Tech for Elektor Electronics. Each book has 300 circuits aimed at the electronic enthusiast, professional or amateur. They offer a comprehension collection of practical ideas, concepts and developments, many of which have been in annual Eleklor magazines, You will find circuits for audio and video, car, cycle and motorcycle, home and garden, receivers and aerials, hobbies and games, measuring and testing, ~ •• -J~ •.. ·. oscillators and generators, current sources and power supplies, microcomputer and music electronics and more. Do you need 10 ,--,.,--,,.--,.--,~ copy old Bela video tapes lo VHS or simply_edil Video 8 to your VCR? Perhaps you simply wish lo dub between lwo _ _ _...__ ~~i':~~:,Rs? eliminates the current patch-cord swapping ritual and provides stereo audio switching as welL The kit provides a monitor and RF oulpul and features CMOS switching with RCA sockets for quick hook up to your VCRs, Jaycar kil comes complete with case, front panel label, video modulator and all specified components_ Plugpack power supply not included, Cal KC-5116 $ J29• 95 Passive lnfrared Detector Barga in Our economy best selling PIR that works extremely well and is ullra reliable, It's so reliable lhal we have increased the warranty period to 1 year. This unit sold for $100 in 1988. Thousands have been sold and are still working reliably all over Australia. Features and specifications: • Dual element pyroelectric sensor. 24 Dual element deleclion zones in three layers • Wide angle 90° multi layer coverage • 12 Meler range• Operation vollage 7.5-16V DC• Tamper protected • LED indication • Size 65(H) x 84(W) x 46(0) • Colour beige • Relay output Cal LA-50 17 1992 catalogue price $49.95 ONLY $39.95 STOCK UP NOW ~""+<~ JAYC, JAYC A Ye JAYC 3~~~ ~~ ~~ -A', ,, All 300 Circuits 302 Circuits Cal BM-2470 $19.95 301 Circuits Cal BM-2471 $19.95 Cat BM-2472 $19.95 303 Circuits Cat BM-2473 $19.95 To give you an example of these circuits - lhe 303 circuit book Includes 32 audio and HI Fi projects, 14 circuits for cars and bicycles, 43 computer and microprocessor circuits, 11 electronics projects, 24 HF and VHF circuits, 16 circuits for a number of hobbies and pastimes, 54 projects for home and garden, 29 power supply circuits, 29 circuil5 lor lest and measurement equipment 9 TV and video project, as well as 42 design ideas AYL ~: ~ t JAY c. ,:~~ JAYC ,:~ ;·g, JA', c JAYC JA, c, BRAND NEW 1992 EDITIONS ~~~~' UP TO DATE WORLD'S TRANSISTORS, DIODES, THYRISTORS JA-c & 1cs, coMPAR1soN TABLES. Vol 1 - A-Z Two voLuMes. JA,c Comparison tables ol lransislors, diodes, thyristors and IC's, Nearly 28,00 types with brief data, pin assignment Over 80,000 comparison and equivalents, Excellent reference book, 967 pages, 110 X150 x 43 (thick)mm, Cat BM-4580 VOI 2 IN 60 000 $19 .95 ' -µ Comparison tables and brief data and pin assignments of another 28,000 types of transistors, diode and ICs of daily use, Over 80,000 comparisons and equivalents givon. 950 pages, 110 x 150 x 42 (lhick) mm. Cat BM-4582 $19.95 Teach Yourself DOS 3.3 & 4.0 By Al Stevens, Teach yourself to set up fixed and floppy disk systems with easy-lo-understand instructions contained in this book, Arm yourself with real lime saving techniques including file maintenance and file protection_ Improve your computer's efticiency and effectiveness, Learn how lo back up and archive files for sale storage, Master easy ways lo handle tricky file directories_ Improve your disk lormalling and copying techniques, Maximised learning - overview of DOS for lhe new DOS user - DOS commands - Paths, fillers, pipes and input/output redirection batch files - EDLIN. 267 pages, 153 x 224mm, $B19:9s :i~:~· ****** The Encyclopedia of Electronic Circuits By Rudolf FGrat This book has a ci rcuit schematic for just about everything you could think of to build, nearly 1,300 in alL They are listed alphabetically and divided into 98 basic circuit categories. For example lhe sections starling wilh the leller A are: Alarms, Amateur radio, Amplifiers, A lo Dconverters, Allenualors, Audio mixers, Audio oscillators, Audio power amps, Audio signal amps, Aulomolive, This is lhe hobbyists and technicians dream treasury of bolh analog and digital circuits, From amateur radio and crossover networks to fibreoplics, lest circuits, motor control, video circuits, limes, elc, wilh special emphasis on slale-olthe-art IC circuit technology_ Also included is a huge index lo specific circu its. A massive 760 pages, size 175 x 230mm. WAS SELLING FOR $69.95 ::~~,,, ,c A, c , A,c, iA,r JI, -C JAV(. JAY( 1AY(., JA'r(...,, JAY(;, iA1 C JArC,, JA'l( ,A,( IA'r'C1 JArL- A', I 1 (A.',f':1 ~ ,A C, JA, A f ,I ' ,',y(', JA'rC, IArC, A '' 'l FLcCTROMC!:, '1 ELECTHONICS RE Lf CTRO IC» 'l ELECTRONICS '1 ELECTRONICS , f ,E JAY CAR .JA,CAR JA1 CAR JAY CAR ,JAYCAR ELFCTRONICc; ELECTRONIC, ELECTRONICS ELECTRONICS ELECTRONICS JA' CAR JA·,CAR JA, C"-R JA; CAR JAY CAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS FI FCTRONICS JA\CAR .JAYCAR JA·, CAR JAY CAR JA,CAR ELECTRONICS ELECTRONICS tLECTRONICS ELECTRONICS FLFCTRONICS JAY CAR JAY CAR JAY CAR JAYCAR .JAYCAR WATERPROOF 1BOPLA 1 WALL MOUNTING BOXES vailable in three sizes. These are TOP quality boxes. They are ideal for housing timers, ntrollers, alarms, e\c, outdoors. They are made from high impact glass reinforced olycarbonatewith a hinged lransparent door. They are divided into two separate sec\ions, hereby providing a suilable means of Interlacing electronic equipment with external wiring. The pper section has integral PCB slots moulded into 4 slides, also filled to the back are tapped nserled (M3) to allow the mounting of a panel or board, which may be extended downwards Into he lower section for interlacing purposes. The lower section has knockouts for conduits or ble in the rear and bottom laces. Both the opening door and \he removable bottom Iron\ panel ave a rubber gasket lo ensure awaterproof seal. Colour is light grey. Operating temperature ange -40°Cto +80°C. Another Jaycar surplus deal which we can offer you these high quality xes at well beloo 1/2 what other suppliers are asking. Three sizes available. Dimensions mm): Depth Depth Widlh Tola\ Door height height al door under door 162 154 96 115 47 46 210 179 116 98 255 212 146 129 55 P R I C E S C A R $34.95 edium size $44. 95 arge size $59.95 1F lE ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS JAY CAR JAYCAR JA\CAR JA\ CAR JAY CAR ELECTRONICS ELECTRONICS ELECTRONICS ELECTRONICS ELFCTR0NICS JAYCAR JAYCAR JAYCAR ,IA vCAR JAY CAR ELECTRONIC!:, ELECTRONICS ELcCTRONICS ELECTRONICS ELECTRONICS JAYCAH JA,CAR JA ,CAR JA, CAR IA\CAR f:LtCl H0NIC!:, ELECTRONICS ELE:CTROMCS FI E-CTRONICS FLEClRONICS JAY CAR ELECTRC JA,CAR ELECTRC JAYCAR ::LECTRC JAY CAR ELECTRC JAYCAR ELFCTRC JAYCAR El Low Cost 1MHz Pulse Generator Kit 3:~g::~: 3~~g~~ ~: eva\ua\ion ofwidebond amplifiers and fillers, frequency compensation of scope probes and adjus\ing other \he attenuators. IT is a must for troubleshooting and developing digital circuits. The project provides BNC a/puts for CROs with single-shot and continuous pulses. THe Jaycar kit comes complete with case, front panel label, PCB and components. $SS.SO Cat KA-1743 · _,-.: .,:··.•: 1 This project is an updaled and improved design that has many features found on expensive commercial generators, but al a fraction of their cost. II can be used for fast JAYCAR E1 JAYCAR u JAYCAR r1 '· cl • .·· ~: Et ··RE. lE .. f fi,, R El JKt~AR El .JAYCAfl .JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR J AYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR .JAYCAR JAYCAR JAYCAR JAYCAR JAYCAR J~YCAR JAYCAR JAYCAR JAYCAR 'CREENAIR' AIR PURIFIER & IONISER 1-9pcs CatHB-6040 We have sold thousands of negative ion generalors over the years. These work by building up avery high negative vollage, generating a stream of negative ion e\ec\rons which are emitted into the air. These ions then attach to particles in the air such as dust which are then allracted to the ground or other solid objects (just as metal filings cling lo amagnet), thus purifying the air. The manufacturer claims the following benefits: • 'Greenair' removes airborne bacteria, dust, unpleasanl odour, allergen and tobacco smoke etc. • Helps sufferers from allergy, asthma, bronchial problems, fatigue, haylever, headache , insomnia and sneezing • Neutralise rx,sitive charges pollulan\s and ions repelled by highly charged TV, CCTV and computer video display terminals • 'Greenair' makes the environment around you a much healthier place lo live in. SPECIFICATIONS Oimensions 105W x 105D x 70H mm, Weight 200g Range 14sq ml (150sq II) Power consumption 240V model 3.8 watts, 12V model 2 walls When we first started selling negative ion generators they were $70. See our 1987 catalogue. II you've ever wondered about negative ion generators grab one of these. 1-9 pcs cat HB-6041 1-9pcs catHB-6042 uantity buyers • 1Ot less 10% off above prices • 20+ less 20% ff above prices Our opposition (\he ones with the really thick calalogue) sell the small size for $72.68 and the large size for $149.08 plus 20% Sales Tax!!!!! l E i r 1f {E- { E 1f- {f 1F TWO l E l E l F MODELS 240V Mains i E 1 f CatYX-2910 1f AVAILABLE 12V DC $29.9S Wilh cigarelle lighler plug $24.9S CalYX-2912 1E 1E l [ n {t l E l E { E : ~ :; ....o connector ·o·ende·r· c11i,n 9 e·r"'"·"· l: l ' ;~ =1 1" 1 E1 1 EI 1' 1 'F bi ~I $ 2 95 ~ ~~ ~~ E E E ~ ~ F ~ E E ~ r f ~ E E ~ ., Enclosure If you have ever wanted to make up a special 25D adaptor, ie to have certain pins connecting belween say lwo sockets, or 2 plugs, ii was very difficult. Now with this new enclosure it's easy. You can now make up all these special adaptors/gender changer elc with a minimum of fuss. Cat PM-0851 • ·• •.•.•......... . . .,. ~-~··..····"·•..,.............•.•.•·"·••.•.•.•..........................................................._... a : ' ~, I iL a E-~--,. =L . ~ ' . •· "• .. iillllll·~• ,.........,,............- ...- ....,,.... .,,....."........ , 6LeedsStreetRhodes2138 T I h 02) 743 5222 eep one ( FAX (02) 743 2066 POST & PACKING $l0 - $24 ·99 $ 3.75 $25- $49.99 $ 4.50 $50-$99.99 $6.50 OVER $100 $ 8.oo 190 Wright SI (Cnr. Selby St) (08) 231 7355 Mon-Fri 9 - 5.30 Fri 8.30- Sat 9 - 12 MasferCard..i BURANDA OLD 144 Logan Rd (07) 3S3 0777 _).!___ .,./' Mon-Fri 9 - 5.30 Thurs 8.30 - Sat 9 - 4 COBURG VIC 266SydneyRd(03)3841811 Mon-Fri 9 _5.30 Fri 8.30 _Sat 9 _4 • • • • • MELBOURNE CITY Shop 2, 45A'Beckett St City(03) 663 2030 s A Mon-Frl 9- 5.30 Frl 8.30- Sat 9- 2 J■■ ~ ■I SPRINGVALE VIC 887-889 Springvale Rd Mulgrave (03) 5471022 ~ Nr Cnr. Dandenong Rd Mon Fri 9-5.30 Frl 8.30- Sat 9 - 2 'I SYDNEY - CITY 117 York SI. (02) 267 1614 Mon-Fr! 830 - 5 30 Thurs 8.30pm - Sal 9- 4 / \ II ADELAIDE SA MAIL ORDERS AUSTRALIA (up to 20kg) $13.50 BANKSTOWN GORE HILL PARRAMATTA JAY<,AK JA, CAR IAYCAR JA,.CAR JAYCAR JAY.CAR tLct,; I H0i',ICS f LEClRONIC'• EU,CTROMCS FLECTRONIC~, ELECTRONICS fl FCTRQNICS JAYCAR JA, CAR Jiu CAR JA,CAH JAY CAR IAYCAR ELECTRONICS JAYCAR Elf CTROMCS ,A, CAR ELECTRO\JICS JA,CAR bLECTROMCS .JAYCAR ELE'CTRONICS JAY CAR FLFCTROMC.S..JAYCAB ELECTRONICS ELECTRONICS ELECTRONICS f-LfCTR0N ICS ELECTRONICS El ECTRQNIC'$ JAYCAR ELfCTRONICS JA\ CAR ELECTRONICS JA\CAR ELFCTR0r...lCS JA\CAR ELECTRONICS .JA, CAR f LECTRONICS .IAYCAR..£llCTRONICS PENRITH RHODES El E E~ El El El El El El El El El El El El El EL El El El El El El El El El El El El El El El El El El El El El El El El El El El El El ,J3~~g~= ~~ " j " iJAYCAREL JAYCAR EL . JAYCAR El JJAAvvccAARR EELL JAYCAR EL · ;t~g:~ :c .JAYCAR El .JAYCAR EL .JAYCAR EL .JAYCAR EL !!!!!!~:________J~:~g:= ~~ MAIL ORDER VIA ff' ~~~g~: ~: P.O.Box185Concord2137 , =.,_ . ·· ........_____.,,, ROAD FREIGHT ANYWHERE IN Vlr ELc\.. 1 tiVNIC.'> f-LECTRONICS ELECTRONICS ELECTROMCS f If CTRONICS ELFC TRQNICS •.[·:, ·;.».f.~=,::: FREE CALL. FOR ORDERS ONLY (008) 022 888 HOTLINE (02) 743 6144 363 Hume Hwy Cnr Meredith St (02) 709 2822 Mon-Fri 9 - 5.30 Thurs 8.30pm - Sal 9- 4 - Sun 10- 4pm 188 Pacific Hwy (Cnr. Bellevue Ave) (02) 439 4799 Mon-Fri 9 - 5.30 Thurs 8.30- Sal 9 - 4pm 355 Church St (Cnr. Victoria Rd) (02) 683 3377 Mon-Fri 9-5.30Thurs 830pm -Sal 9- 4pm Su nd ay 1oam - 4pm 199 High St (047) 21 8337 Mon-Fri 9-5.30 Thurs 8.30- Sal 9-4pm Sun 10-4pm 6 Leeds SI (02) 743 5222 Mon-Fri 9 - 5.30 ,JA\CAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR JA.<CAf1 ELECTRONICS JAYCAR ELECTRONICS JAYCAR JAYCAR ELECTRONICS JAYCAR E'LECTRONICS,JAYCAR JAYCAR ELECTRONICS JAYCAR ELECTRONICS JAYCAR JAYCAR EcLlCTRONICS JAY CAR ELEcCTRONICSjJAYCAR JA~CA.8..ELECIB/'lf\llCS IAYCAR JAYCAREL JAY CAR EL JAYCAR EL ~~~g~: ~~ ~~~g:~ ~~ JAYCAR EL JAYCAR EL ~~~g~= ~~ JAYCAR EL JAYCAR EL ~~~g~: ~~ JAYCAR EL JAYCAR EL ~~~g~= ~~ ~:~g:: JAYCAR EL ~~ ELECTRONICS JAY CAR ELECTRO! ELECTRONICS JAYCAR ELECTRO! fLECTR0NICS JAYCAR ELECTRO! ELECTRONICS JAYCAR ELECTRO! ELECTRONICS JAYCAR ELECTRO• cl ECJRUNu..;:,...LB.lJC' ...filw:J..c.L.Ltll.JJ What's New In Oscilloscopes? Is it some time since you last looked at what's available in oscilloscopes? In this article, we'll update the oscilloscope scene, with special emphasis on CRT readout and the new digital storage models. By LEO SIMPSON In the last two years or so, For those not familiar the oscilloscope market has with CRT readout on changed radically. Convenscopes, we'll explain. Intional analog scopes are bestead of just having one, ing more and more overtwo or four· traces on the shadowed as digital storage screen, CRT readout scopes models become more powalso display the principal erful and also cheaper. At settings for the vertical senthe high end of the market, sitivity, timebase (sweep you can now obtain digital speeds), AC or DC input scopes with repetitive bandcoupling, probe settings widths up to 50GHz, a figand so on. The letters and ure undreamt of not so many numerals shown at the top CRT readout scopes can have simplified controls without years ago. and bottom of the scope a lot of labelling to clutter up the control panels since the But before we get carried screen are generated in exsettings are displayed on the screen. The Kikusui model COR5500 series are a very good example of this and have away with where the maractly the same way as are very clean and easy to use control panels. ket is heading, let's back up the alphanumeric characa little and see where it's ters on a computer screen. been. This is an interesting For quite a few years now, the basic will have even greater bandwidth, up contrast because while the scope oscilloscope has been an analog model to 150MHz or more, and perhaps four traces are generated by the method of with two channels, 20MHz band- instead of two channels. To provide "vector scan" whereby the CRT beam width, a maximum vertical sensitiv- the much faster trace writing speeds moves in direct response to the ity of 20mV/ division and a maximum required for these higher bandwidths, voltages applied to the vertical and sweep speed of 20 nanoseconds/divi- the oscilloscope tube will generally horizontal plates, the alphanumeric sion. Such an instrument can do a be a PDA (post deflection accelera- display is produced by a raster scan tion) type with a spiral anode running method (see the glos,sary accompanywide range of tests on audio and video equipment, logic circuitry including the full length. Inevitably, this adds to ing this article). computers and on some communica- the price. This means that the scope traces tions equipment. must spend some part of the time The next step up in features is to CRT readout scopes being "raster scanned" and the rest of Higher priced analog scopes now the time being "vector scanned". The have higher bandwidth, say 40MHz, and perhaps a delayed timebase which commonly have CRT readout, a feasharing of the trace between these enables you to more easily display ture introduced quite a few years ago two tasks is controlled by a micropulse waveforms with short duty cy- by the major manufacturers, Tektronix processor inside the scope and this cles and to be able to measure pulse and Hewlett-Packard. CRT readout is also takes care of the alphanumeric rise and fall times. a major innovation and also means a character generation. Higher priced analog instruments big increase in circuit complexity. Why have CRT readout on scopes? JUNE 1992 53 The overwhelming reason is to make them easier to use. Because scopes have so many knobs and buttons, with 20 or more settings in the case of the timebase controls, they can be very confusing to drive. In the middle of a complex measurement setup, particularly where delayed timebase settings are being used, it can be very easy to "get lost". The trace can "get lost" too and when this happens, it can take quite some to get your bearings and come to grips with the measurement. This is where CRT readout scopes excel. Because they display the principal settings on the Screen, you have a much better grasp of what the instrument is actually doing. You don't need to do anything special to display the measurement settings on the screen; it happens automatically. And each time you change a setting, say the timebase or vertical attenuator setting, the appropriate alphanumeric display changes automatically. And because all the settings are shown on the screen, the labelling of the front panel can be greatly simplified, which again makes the scope easier to drive. Apart from making a scope that This Kenwood CS-5170 100MHz CRT readout scope is displaying a standard PAL TV colour bar pattern, along with the channel 1 vertical attenuator setting of 0.5V/div and the timebase sweep speed of 20µs/div. much easier to use, the CRT readout has one big additio_n al benefit: if a photograph is taken of the screen, the measurement settings are also recorded. Screen photos In the past, the accepted method for recording screen information has been to take a photo with a specially designed Polaroid camera using fast film. As we shall see, digital storage scopes come with computer interfaces which allow screen and measurement data to be stored in computer memory for later retrieval. And some digital HITACHI COMPACT SERIES SCOPES CRT READOUT AND CURSOR SCOPES . V-1065A DC to 100MHz V-665A DC to 60MHz CRT READOUT SCOPES V-1060 DC to 100MHz V-660 DC to 60MHz Dual channel, delayed sweep, CRT readout , cursor readout (not provided on the V-1060 and V-660) , frequency counter (not provided on the V-1060 and V-660). sweep time autoranging, trigger lock. Hitachi Compact features CRT Readout, Sweep Time Autorang _ ing and Trigger Lock Functions. . . ST LUCIA ELE V212 AT $719 + TAX (V212 NOT SHOWN) AND "FLUKE" SCOPE METER'S FROM $1459 + TAX. ~ 54 SILICON CHIP HITACHI S . . 24 Campbell St. Bowen Hills Q 4006. Tel: (07) 252 7466 Fax (07) 252 2862 ECONOMIC ELECTRONICS: 22 Campbell St. Bowen Hills Q 4006. P.O. Box 481, Fortitude Valley 4006. Tel: /07) 252 3762. Fax /07) 252 5778. SOUTHPORT ELECTRONIC ~~if~tR°8 J:211£ Welch St. Tel: /075) 32 3632. Fax: /075) 51 0543. Electronics Workbench® The electronics lab in a computer! A simple, intuitive and very powerful teaching tool, Electronics Workbench lets students and hobbyists design and test both analog and digital electronic circuits, without the delays and expense of a laboratory • Yokogawa's DL1200 and DL1100 storage scopes have large memories for long waveform storage. They incorporate an optional printer but can also feed an external HP-GL printer or laser printer. FEATURES scopes, such as the Yokogawa DL-1200, come with an optional inbuilt printer, making a Polaroid scope camera unnecessary. LCD readout One manufacturer that has provided an alternative to CRT scopes has been Philips but they still recognise the need for displays of principal settings. Their method is to use a separate backlit liquid crystal display to show this information. It is probably even easier to read than CRT readout scopes but it cannot be recorded by means of a photo of the screen. We should note that most Philips digital storage scopes have CRT readout as a matter of course. • Quick and simple circuit entry • Digital and Analog Modules included, complete with all components • Simulated instruments: dual trace scope, spectrum analyser, function generator, multimeter, digital word generator and logic analyser • Complete control over all component values and parameters • Print: circuit schematics, parts list, instrument readings, macros • Logic conversion - truth table to Boolean formula to logic gates • Customisable hypertext help system THREE VERSIONS • Professional Version: EGA/VGA colour display; unlimited components • Personal Plus Version: Monochrome display; unlimited components • Personal Version: Monochrome display; limited to 20 components per .. EMONA INSTRUMENTS NSW ......................... (02) 519 3933 VIC ............................ (03) 889 0427 QLD .. .. ...................... (07) 397 7427 DISTRIBUTORS Perth .. ..... (09) 244 2777 Adela Ide .................. ...... (08) 362 7548 Hobart .. .... ... ...... .. ........ .. (002) 34 2233 EmonaLAB4 Four instruments in one package! Intelligent scopes On the even more upmarket scopes with CRT readout, the internal microprocessor is employed to do measure- The LAB4 has four full function test instruments: ■ DC POWER SUPPLY Triple output; 5V, 15V, 0-50V ·~ ~~p :i ■ DIGITAL MULTIMETER Full function, auto-ranging ■ FUNCTION GENERATOR 0.02Hz-2MHz, with SWEEP ■ FREQUENCY COUNTER 1Hz-100MHz input range Digital storage scopes can generate a lot of data and are most useful when they can be used to compare waveforms with previously stored signals. This Tektronix TDS640 (which has a sampling rate of 2 gigasamples/sec) is shown with the Tekemate TD100 which has a 50Mb hard disc and 1.44Mb floppy drive. All storage, recall and other functions are selected from menus on the scope screen. with neatly laid out and labelled front panel controls. Also, the LAB4 is compact and only takes up a small space, compared to four bench-top instruments. INDEPENDENT INSTRUMENTS Each instrument in the LAB4 is completely independent and can be switched ON or OFF as required. The LAB4 has only one 240V mains input, saving on multiple power points . Each instrument is clearly defi ned EMONA INSTRUMENTS NSW ......................... (02) 519 3933 VIC ............................ (03) 889 0427 QLD .......................... (07) 397 7427 DISTRIBUTORS Perth .. ... .. ... ... . .. .... ... (09) 244 2777 Adela ide ...... ... .. .... .. .. ... .. (08) 362 7548 Hobart ... . . ....... . .. . .... . (002) 34 2233 ]UNE 1992 55 --y ,_. ~ y~-,----=-...~--------,""""-., . . . EJ e1. ••! d. ,. .,.EJ -~· (::. . _b ., / .,~ ' This and other CRT readout scopes can also display time and date and other information which may be useful in later documentation. And finally, some of these "intelligent" analog scopes have digital outputs to enable screen signals to be sent to a printer or computer. Digital storage scopes Hewlett-Packard have been pioneers in the development of digital storage scopes and more latterly of raster scan models such as the 54601A 100MHz unit pictured here. HP has also just released the 54602A 4-channel model which has a bandwidth ofup to 250MHz. ments automatically. This adds little extra to the circuit complexity of the unit but greatly increases its use as an all-round measurement tool. For example, the Hitachi V-1150 150MHz CRT readout oscilloscope also incorporates a 150MHz frequency meter function and a wide bandwidth AC and DC voltage measurement func- tion which includes relative measurements in decibels. It will also measure and automatically display pulse rise and fall times, periods, overshoot, droop and so on. It also has moveable vertical cursors for time (period, rise time, etc) measurements and moveable horizontal cursors for voltage measurements. While analog scopes have been able to cope with most measurement situations, some types of signals have always presented a problem. How do you measure and display a waveform or signal which only occurs occasionally or is very fast? For example, all switch contacts bounce when they close and this leads to troublesome transient pulses. In the past, the way to display such single shot phenomena has been to use an oscilloscope tube with a special mesh structure behind the screen. The mesh was used to store the screen pattern so it could be displayed long enough for visual examination and to allow photos to be taken. Alternatively, some storage tubes had a secondary target and flood gun system to achieve much the same function. Patterns could be stored for about an hour. Some scopes have also had Glossary Alphanumeric characters: letters and numbers which may be displayed on the screen of a scope to show the principal settings being used. These are generated by an internal microprocessor in a similar way to that used on a computer monitor. Bandwidth: maximum frequency which can be displayed on the screen for a reduction in vertical deflection of 0.707 (ie, -3dB or half power point.) For example, a 20MHz signal displayed on a scope with a 20MHz bandwidth could be expected to display 70% of the amplitude of a signal at 1MHz. Beam: the electron beam from the cathode of an oscilloscope (CRT) tube. Usually the beam is split to give two or more traces, depending on the number of input channels. CRO: abbreviation for "cathode ray oscilloscope". This term is falling 56 SILICON CHIP into disuse and is being replaced by "scope". CRT: abbreviation for "cathode ray tube" which is the heart of any oscilloscope, TV or computer monitor picture tube, radar display, heart monitor and so on. A scope CRT has voltages applied to the vertical and horizontal plates which cause the electron beam to trace out a pattern on the electroluminescent screen. Quantising: process by which sampled signais are converted to digital data. Raster scan: method by which a display is produced on the screen of a TV set or computer monitor. The electron beam is scanned continuously and rapidly over the entire surface of the screen and then modulated to produce areas of light and shade in the case of a monochrome picture, or modulated on and off to the produce the dot ma- trix displays of computer monitors. Raster scan is also used on CRT readout scopes to produce alphanumeric displays. Sampling: process by which the signal levels of a waveform are taken by a digital to analog converter. These sampled signal levels are then "quantised" to convert them to digital data. For repetitive signals, the sampling rate must be at least twice the signal frequency. For non-repetitive signals, the sam-, pling rate must be at least 10 times the signal frequency in order to capture the waveform with reasonable fidelity. Vector scan: method by which voltages applied to the vertical and horizontal plates of an oscilloscope tube move the beam to trace out waveforms on the screen. Word: parcel of digital data or unit of memory in digital storage scope; usually eight bits. ~010000 Whether you speak 01010011 or analog, Philips provides you with a complete analog and digital oscilloscope in one instrument. With a sampling rate of 200 megasamples per second and a bandwidth up to 200 MHz our easy- to-use 4-channel oscilloscopes represent state-of-the-art technology. With direct access functions. Innovations like aprobe mounted button which allows you to recall set ups. Perform Autoset. Freeze display as well as display measured results. In the analog mode, extremely fast update and infinite display resolution allow you to see three dimensionally. For instance, the distribution of time-jitter. The digital mode is impressive. Logic triggering creates a true 4-channel logic analyzer. It is prepared for HDTV triggering. The powerful 0SO specifications_ give you extensive trace storage possibilities. And processing capabilities like FFT. At Philips, we're on your wavelength. Which is why we promise you one thing. You'll measure b~tter performance For further information please contact your local Philips Test & Measurement Organisation: SYDNEY (02) 888 0416 MELBOURNE (03) 881 3666 PERTH (09) 2TT 4199 WELLING.TON (04) 88 9788 BRISBANE (07) 844 0191 ADELAIDE (08) 348 2888 AUCKLAND (09) 89 4160 PHILIPS Tektronix was one of the pioneers of CRT readout scopes. Their model 2211 is a digital storage oscilloscope which uses a conventional CRT. variable persistence phosphors which enabled one-shot signals to be more easily examined. Such oscilloscope tubes were very expensive, had limited brightness and tended to bloom if you attempted to turn up the brightness. The tubes also did not last very long, especially if they were often used in storage mode. With the great expense of analog storage scopes, it was inevitable that logic circuitry and computer memory would eventually produce a digital storage oscilloscope. The first fully digital storage scopes by Hewlett Packard (HP54100) were introduced about 10 years ago. Since then, they have progressed gradually, with increasing bandwidth, sampling rate, memory and measurement functions. One of the new breed of LCD scopes, the Fluke Scopemeter combines a 50MHz digital storage scope and a 3000 count digital multimeter. 58 SILICON CHIP To date , most digital storage scopes have been a marriage of conventional analog scope technology with digital storage circuitry. These scopes can function as conventional analog instruments and are used in the digital storage mode only when necessary. Other digital storage scopes can only be used in digital mode. To display a signal on the screen, you set up the recording parameters, push a button and then the trace appears on the screen. They are powerful instruments but their very power makes them difficult to drive. All digital storage scopes have broadly the same internal circuit functions. First, they have attenuators for the input channels and the signal either passes to the vertical deflection amplifiers when in the analog mode or to the digital to analog conversion circuitry when in the storage mode. The signal is sampled, quantised and the digital data stored in memory. It can then be read out of memory, converted back to an analog signal and displayed on the screen. The beauty of having signals stored in memory is that, with suitable software, they can be stored indefinitely, for display at any time. Raster scan scopes In the past year or so though, the scene has changed quite radically with the introduction of digital scopes like the Hewlett-Packard 54600 series, the Yokogawa DL 1100/1200 series and similar machines from Tektronix, Le Croy and others. Two factors make these scopes different from earlier digital scopes. First, they do not use the expensive scope tube which is typically 40cm long or longer. Instead, they use a CRT which is just like that in a computer monitor and the display they generate is composed entirely of dots, not just the alphanumeric information. Because of this , they can display waveforms which move much more slowly or a great deal faster than possible on an analog scope and do it without having the trace becoming unusable. Second, this new generation of scopes can now respond to signal and measurement changes in such a way that they appear to behave exactly the same as analog scopes. Because of this, they are much easier to drive easier even than analog scopes. (To gain an insight into these new instru- like the feeling·of our new 1gital troubleshooting scope. Now there's a 100 MHz digital scope that handles just like analog. instantly to the slightest control change. Digital oscilloscopes have certain advantages that are hard to overlook. But for troubleshooting, many engineers still prefer analog scopes. Simply because they like the way they handle. But when it comes to troubleshooting, the HP 54600's digital performance leaves analog and hybrid scopes far behind. At millisecond sweep speeds, the display doesn't even flicker. Low-rep-rate signals are easy to see without a hood. The HP 54600 changes that. It looks like a 100 MHz analog scope. All primary functions are controlled directly with dedicated knobs. And itfeels like one. The display responds It has all the advantages that only a true digital scope can provide. Like storage, high accuracy, pretrigger viewing, hard copy output, and programming. And since it's one of HP's basic instruments the HP 54600 gives you all this performance at a very affordable price. So if you like the feel of analog control, you'll like the way our new digital scope handles troubleshooting. To find out more call the Customer Information Centre on 008 033 821 or Melbourne 272 2555. [hi] ~i~KLi~6 A Better Way. Just released: the HP 54602A scope with bandwidth up to 250MHz JWT HTM I 25/A - ~ .c"'"':::: OSOLI.DSCCPi .... oovoOOV►.1' 9 f !'0$:(fQI c:::, ~=~ 1,,00IC sco,-e 'ltw.'lCAl. Jo CH 1u1tll ~0 CH1"i/•llU5 l_ltY r ·='"'"'2::: .. 'lO'ol · - ~<( ► CH2 , r, Another of the new breed of LCD scopes, the Leader 300 is a dual channel storage unit with a sampling rate of 30 megasamples/sec & a bandwidth of 10MHz. It can record one-shot events with signals up to 3MHz. It can also function as a data logger, 8-channel logic scope and a digital multimeter. ments, refer to our review of the HP 54600 series in the October 1991 issue and the review of the Yokogawa DL1100 series in the April 1992 issue.) Interestingly, once the input signal is converted to digital data in these scopes, it is not converted back to an analog signal for subsequent display. Instead, the signal is converted in order to produce a dot matrix display, just as on a computer screen. Because the signal display is en- tirely made up of dots, there are no problems with the trace becoming faint when displaying very high frequency signals or becoming just a very bright dot when displaying very low frequency signals. In just about all measurement situations, the raster scanned scope can produce a display which gives as much, if not more, information and it will generally present less problems in producing a steady display. And even if the signal is rapidly changing, the display can The Le Croy 7200 series digital scopes have a bandwidth of 500MHz and a sampling rate of 2 gigasamples/sec. They are equipped with an internal hard disc for data logging and a floppy drive for waveform storage. 60 SILICON CHIP be frozen to enable you to examine it at leisure. Having said that, there will be times when the display from an analog signal is significantly different to that produced on a digital scope, for the same signal. This does not necessarily come down to a matter of one scope being right and the other one being wrong. It is more a matter of correct interpretation. Over many years, technicians and engineers have become expert at interpreting the displays on analog scopes. In some cases, they will have to learn how to interpret the displays again when they see the signals on a digital scope. Just about all digital scopes are available with interfaces which enable them to be hooked up to computers or printers. Two interfaces aie the most common: RS-232 and IEE-488 or GP-IB (HP's General Purpose Instrument Bus). With appropriate software, not only can data be collected via the scope but its operating parameters can be changed under program control. LCD scopes Finally then, there is the new generation of LCD scopes, as typified by the Fluke PM97 Scopemeter. This uses a green backlit LCD screen and can display signals up to 50MHz. It combines a 3000 count digital multimeter, making it a potent tool for work in the field away from mains power. And which one is ideal for you? Your budget is the first consideration as scopes today range in price from just under $500 to $50,000 or more. For most applications, the analog scope functions very well but it is being gradually supplanted by the digital scope. And while today, the analog scope has the bulk of sales, in five years time or less, digital scopes can be expected to have the major part of the market. They are dropping in price and improving in performance. In just about all test applications, you can find a storage scope which will do the job as well as, if not better, than an analog scope. And its ability to be programmed, to recall waveforms and to produce a rock-steady display is rapidly putting the analog scope in the shade. Where the analog scope will continue to hol.d its own is where waveforms need to be displayed with utmost accuracy and where noise must not be hidden in jitter. SC I PRODUCT SHOWCASE Low priced meters from Fluke Fluke has released a low-priced, durable range of digital multimeters. The Fluke 10 Series is designed for three types of users: the electronics repair person, the electrical troubleshooter and the enthusiast who wants the quality of a Fluke meter. The series consists of three meters. The model 10 ($90) is the baby in the range. It is autoranging and checks AC & DC volts, continuity/diode test and resistance. The autorange function may be manually overridden. Model 11 ($115) adds capacitance measurement and a new feature called "V-Chek". This is an extension of the ohms/continuity position. The user sets the meter to V-Chek, probes the power supply or source and the meter automatically tells you if the circuit is open, continuous or if voltage is present. If a voltage greater than 4.5V is de- tected, the meter will switch from continuity/ohms to volts and display either AC or DC volts, which ever is greater. In addition, the input impedance is low (2kQ) to distinguish "real" voltage and avoid false readings arising from "ghosting" due to leakage. The top model, Model 12 ($130), incorporates all the features of the Model 11, with a mini max recording mode with a relative time clock. The minimax function records the highest and lowest voltages and the meter's internal clock records when the minimum and maximum occurred during a 100-hour period. When the recording mode is acti- Surface mounting transformers Siemens now offers complete transformers in the form of surface mounted components. Typical applications are in digital communications technology, power supplies and for triggering power semiconductors. For further details, contact Malcolm I vated in the continuity position, the unit will capture and provide a symbolic display of opens or shorts as brief as 250µs, making it useful for capturing intermittent shorts or opens. Accessories include a yellow holster with stand and a soft padded case. The new Fluke range of multimeters is widely available from electronics retailers throughout Australia. Evans, Electronic Components Department, Siemens Ltd, 544 Church St, Richmond, 3121. Phone (03) 420 7716. Laser diodes from Sharp Sharp's LTO15 series of laser diodes have a wavelength typically of 830nm, 40mW optical output power AT motherboard from Rod Irving If you're still clunking around with an old XT, now is a good time to update your machine with a new AT motherboard. This 16MHz AT motherboard from Rod Irving Electronics costs only $199. It has space for up to 4Mb of RAM using four SIPP modules or 1Mb of RAM via combinations of DIL packages. The board also has five 16-bit and two 8-bit expansion sockets, as well as a socket for an optional 287 coprocessor. Its overall dimensions are 330 x 220mm, making it reasonably compact. It also comes with expanded memory driver software and a jumper setting sheet. For more information, contact Rod Irving Electronics in Sydney or Melbourne. JUNE 1992 61 Electronic load has choice of modes The Beha Uniwatt EL 500 electronic load is intended for quick and accurate simulation of DC power consumption for testing applications. The standard version has a maximum power of 500W, an input voltage range of 0.5-60V, and a load current range of 0-50A. The user can select the following operating modes: constant current, constant resistance or 100Hz/ 1kHz pulse loads. The voltage and current values are displayed by two separate 3-digit LED displays. In order to allow for measurement and documentation of the load current with external devices such as recorders or oscilloscopes, the EL 500 is equipped with an additional current monitor output. There is protection against excess power, overvoltage , overcurrent, reverse polarity and over temperature to prevent the unit from being damaged by incorrect operation. For further information, contact Paul Twigg, Elmeasco Instruments Pty Ltd, 18 Hilly Street, Mortlake, NSW 2137. Phone (02) 736 2888. tween 4mm and 26mm. The new range of PTC thermistors is intended for overload protection in consumer electronics and for data processing equipment. For more information, contact Malcolm Evans, Electronics Components Department, Siemens , 544 Church St, Richmond, Vic 3121. Phone (03) 420 7716. Ultrabright amber LEDs and come in a standard low cap type package (D type) or fin package (F type) with single transverse mode. Each Sharp laser diode package has a built-in photodiode which makes it easy to control output power. They have wide applications in medical equipment, optical communications and data processing equipment. For further information contact Manuco Electronics, 31 Agnes Street, Jolimont, Vic 3002. Phone (03) 650 3977. Thermistors for high ambient temperatures Siemens now offers a range of line voltage (250VAC) overload protection PTC thermistors with a reference temperature of 135°C. They are specifically suited for applications with increased ambient temperatures. The C811-C891 is rated for currents from 30-690mA and for switching currents from 65-1430mA. The size of the PTC thermistor discs varies be- SUPER BARGAINS - BULK PACKS & KITS All prices $A include sales tax. HURRY lor stocks at current prices. Ask about Student Discount. 1/4W CARBON FILM RESISTORS PASSIVE INFRAffED SENSOR PCB MOUNT SWITCH Quality Dual Element PIA SENSOR (with data sheet) plus PCB MOUNT FRESNEL LENS $8.76/set with changeover contacts to Pack $7.27 LINEAR CAPACITORS DIODES & LEDS IN4004 100 Pack $6.20 W0410 Pack $3.95 RED LED 5MM 100 Pack $8.30 GREEN LED 5MM too Pack $10.60 LM380 10 Pack $13.05 LF35110 Pack $7.27 TL06410Pack$11 .17 LM324 10 Pack $5.05 NE553410 Pack$15.16 0.1µF 1OOV mylar 100 Pack $3.50 10µF 50V electro 100 Pack $5.90 CMOS - 10 Packs 4013 $5.52 4060 $8.04 4049 $5.02 4066 $5.56 4050 $5.52 40106 $5.52 OPTO-COUPLER 4N25 10 Pack $6.95 LIGHT ALARM KIT Sounds when light enters protected area. $12.41 CPUs ZBOA CPU $3.76 each 62 SILICON CHIP Any Normal Value 100 Pack $1.40 VOLTAGE REGULATORS LM7805 10 Pack $6.67 LM7905 10 Pack $6.39 LM723 10 Pack $6.76 2716 5 Pack $38.00 211410Pack$19.43 61165Pack$18.50 CONTINUITY TESTER & LONG LIFE FLASHER KIT Can distinguish between resistances in the range 0.1 lo 500 ohms. $13.93 CRYSTALS 4.0000 MHz 5 Pack $6.11 4.1943 MHz 5 Pack $6.11 Game of skill to reach top of stairs. $21 .98 MEMORY STAIRWAYTO HEAVEN KIT Pack, Post & Ins: Aus $5, NZ $12 Discount: $5 off next order for orders over $150. Valid for 3 months. Orders: Tel. (03) 751-1989 or PO Box 934, Mt. Waveney, Vic. 3149. Allow 14 days delivery. Bankcard, Visa, Mastercard Minimum $15 1000s of Components ·Respected name brands. •All bargain prices. ·catalog free with order. Hewlett-Packard has announced a series of ultrabright amber and reddish-orange light-emitting diodes (LEDs) which are 10 times brighter than existing amber LEDs and bright enough to be visible in sunlight. The HLMA series of LEDs is suitable for outdoor applications in automobiles, moving-message panels and traffic-control signals, as well as indoor applications that need a lowcurrent light-source alternative; eg, the front panels on office and medical equipment. The amber HLMA-BLOO LED offers a highly focused viewing angle (3°) and an average intensity of 8.4 candelas at 20 milliamperes (mA). The amber HLMA-CLOO LED has a slightly wider viewing angle (10°) and an intensity of 1.3 candelas at 20mA. The HLMA-DGOO and the HLMADLOO LEDs come in reddish-orange and amber, respectively, with a viewing angle of 34° and a typical onaxis intensity of 650 millicandelas at 20mA. For further information, contact David Segal at VSI Promark Electronics Pty Ltd, PO Box 578, Crows Nest, NSW 2065. Phone (02) 439 8622. General purpose scanner for Dl\1Ms Yokogawa has released their general purpose 7501 Programmable Scanner. It offers up to 50 channels in a variety of switching configurations and is designed to connect to most types of digital multimeters, thermometers and similar instruments to provide an automatic test and measurement or data logging system. Switching configurations are provided on four different types of relay cards, including 3-wire scanner, 4-wire scanner, a power actuator card and a non-blocking EMS turbo memory board Want to expand your computer's memory beyond its current capacity without going to a new motherboard? This new EMS turbo memory board from Rod Irving Electronics caters for the LIM EMS 3.2 and 4.0 standards and can accept up to 6Mb of RAM. It can be easily configured in either 8 or 16-bit mode for XT / AT or 386 systems and as extended or expanded memory. It also supports the use of 411000 and 414256 dynamic RAM chips. The board fits directly into one of the expansion sockets on the motherboard as a standard card. r;J ~ ~ ~ E.:':'! t-=r!!:'!. ~e~ ,>1»,..t<t _ For many years you have probably looked at satellite TV systems and thought "one day". crossbar switching card. A digital input output card is also offered. The 7501 may be controlled via its GPIB interface, a 100-step program stored in its internal program memory, or on a 512Kb memory card. For further information, contact Tony Richardson at Yokogawa Australia Pty Ltd, Centrecourt D3, 25-27 Paul St North, North Ryde, NSW 2113. Phone (02) 805 0699. You can now purchase the foll owing K-band system for only: $995.00 Here's what you get: *antenna, A 1.8-metre prime focus dish complete with all th e mounting hardware. * One super low-noise LNB (1 .4dB or better). *magnetic One Ku-band feedhorn and a signal polariser. * 30 metres of low-loss coaxial cable with a single pair control line. *receiver lnfrared remote control satellite with selectable IF audio Included with the card is a utility disc which contains useful programs, including an expanded memory manager, printer spooler and RAM disc. It comes with a comprehensive 18-page manual for the software and a 28-page & bandwidth, polarity & digital readout. Your receiver is pre-programmed to the popular AUSSAT transponders via the internal EEPROM memory. Th is unit is also suitable for C-band applications. Call, fax or write to: AV-COMM PTY LTD PO BOX 386, NORTHBRIDGE NSW 2063. Phone (02) 949 7417 Fax (02) 949 7095 user manual for the board. The EMS Turbo memory extension board costs $299 (no memory fitted) and is available from any Rod Irving Electronics store. Samtec micro headers & socket strips Samtec has released the TMS series of headers and socket strips. The headers are on 0.05 x 0.1-inch centres and include straight and rightangle options on single or double rows, with up to 36 positions per row. Double row headers can be used to mate with Samtec's FSS IDC cable assemblies on the same centres. Straight pin headers in single or double rows can be mated to the new low profile socket strips (SLM series) and standard profile socket strips You can now afford a satellite TV system [H- 1[]5 All items are available separately. Ask about our C-band LNBs, NTSCto-PAL converters, video time date generators, FM 2 & EPAL & Pay TV hardware. ·----------(SMS series). These combinations are ideal for board stacking applications. Board-to-board dimensions range from 0.28-0.78 inch. For more information, contact NSD Australia, 205 Middleborough Rd, Box Hill, Vic 3128. Phone (03) 890 0970. I 1 YES GARRY, please send me more InI formation on K-band satellite systems. II Name ................ .. ... .... .......... .. ... .. .... . I II I Address ..................................... .... .. I I ........................... P/code ............... .. II Phone ...... .. ............ ....................... ... I I I II I I ACN002174478 01/92 ·-----------.1 JUNE 1992 63 New Grundig VCR has archiving facility Grundig has released a new video recorder that does more than just play tapes. It has an on-screen tape archiving system as w ell which can save you from the tedious task of searching through racks of cassettes for that old movie. Previously recorded cassettes can be manually entered into the system and new tapes are automatically catalogued. Recording times, titles and the time remaining on the cassette, as well as subject categories, are all displayed on-screen. Tapes are each given a code for identity purposes, with a letter representing the subject category. The archive has a summary page and cross reference facilities for up to 700 cassettes. This can be extended to 1400 cassettes with an extra memory IC. A keyword search quickly locates your old movie and tells you what tape it's on. Once tapes are on-line, an automatic process indents each new recording with date, duration, remaining free-time and elapsed time on tape. In addition, a sensor calculates the playing time of each tape as it is loaded into the machine. Apart from the archive facility, the new Grun dig VCR is a hifi stereo video recorder with seven heads. It features a flying erase head for smooth insert and add-on editing, long play facilities, VPS scanning and access to all features via the remote control. The retail price is $1769. For more information, contact Southern Cross Electronics, 28 Kent St, Belmore, 2192. Phone (02) 750 3166. Instrumentation amplifier 900µA and operates from ±2V to ±18V. Applications include weigh scales, ECG instrumentation, data acquisition systems and process control. The chip is available in both industrial and military versions and comes in either an 8-pin DIP or SOIC (surface outline) package. For more information, contact Ian Laidlaw, at NSD Australia, 205 Middleborough Rd, Box Hill, Vic 3128. Phone (03) 890 0970. Analog Devices has now released the AD620, an instrumentation amplifier that outperforms traditional discrete designs using three op amps and associated resistors. The AD620 can be used wherever differential signals must be distinguished from common-mode signals. The chip typically consumes only ~,. ~ ;§ ~~~ A look at some of the best Model Railways in Australia . ··. --- ~ .~ ~ - -- -«~ { . . * lnch.i<les Australian, European, U.S. and U.K. layouts in all scales * Coinpareprot~type'locations in Australia with the Mo<lel Layout :·, ~ : ·- . . _ ·- . * Vlsital! iii~recent exhibitions around Australia · * All technical detaiLexplained This is a highquality Broadcast Production featuring: CHOO-CHOO-CAM Available from: ACTIVE MEDIA IMAGES A Micro Camera mounted atop locos as they move around the layout PO Box 90, Riverwood, N.S.W. 2210 Phone: (02) 580 8525 60 minutes Running Time Cheque, Money Order, Bankcard, MasterCard or Visa 64 SILICON CHIP LCD colour video projector Sanyo has released an LCD colour video projector for applications such as large screen visual presentations and entertainment at home. The PLC100PP will operate with any of the four major television systems and accepts A-V signals from any VCR, 8mm camcorder or laser disc player. The projector is lightweight, compact and portable. Set-up requires only size and focus adjustments. A remote control unit has all the standard functions as well as a motor-driven zoom function for close-up (2x), images. The picture can be adjusted from 53cm to 3000cm (diagonal) and rear projection is possible with the unit's left/right picture reverse scan facility. A built-in amplifier allows stand-alone operation, or a sound system may be connected to the audio output on the rear. Retail price is $7500. For more information, contact ·wally Fabejewski at Sanyo Australia on (02) 763 3822. ~ =III/J/Jll!-- The electronics magazine for the enthusiast Four good reasons why you should subscribe to SD,IIJOl\T CH i P 1. You get a 12.5% discount on the newsstand cover price. Last year, we had to increase the cover price of the magazine because of rising costs but we have held the subscription to the old price so you get the benefit. 2 • You'll never miss an issue. Sometimes it can be very hard to find SILICON CHIP in the newsagents because it sells out early or gets buried under other magazines. By taking out a subscription you don't have to search for it - it arrives in your letter box in mint condition. We wrap it in tough plastic to make sure of that. 3 • Get a discount on the binder too. You'll want to store and protect your issues of SILICON CHIP so when you take out a subscription you get a further discount on the binder. By taking out a 2-year subscription and buying two binders at the same time, you get even bigger savings. And we despatch the binder(s) with your first issue so you have it right from the start. JUNK MAIL 4 • From time to time, we will have special promotions and offers in the magazine, like the Bose Lifestyle competit- ion featured in the September to December 1990 issues. When you are a subscriber you are automatically eligible for these and you get the chance to benefit. Interested in these savings and benefits? Just fill in the coupon on the fallowing page and send it with your remittance. You'll be glad you did. Why not do it today? I hope to see you as a supporter soon. Leo Simpson, Publisher Most magazines sell their subscriber lists to mail order companies, to earn extra income. Be assured that we will not do this. Your privacy will be respected and you will not be deluged with unwanted mail. MAGAZINE BINDERS Specially designed binders for SILICON CHIP are always available. Made with a distinctive high quality 2-tone vinyl, you can obtain them at a discount when you take out or renew your subscription. The price details are on the coupon overleaf. Just fill in the order form on page 93 ~ JUNE 1992 65 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. 01 1N4001 Loudspeaker protector has power-on delay This loudspeaker protector and antithump circuit is similar to one presented in the July 1991 issue of SILICON CHIP. It differs mainly in the way it monitors for the presence of the mains supply. Transistors Ql, Q2 & Q3 monitor the two outputs of the stereo amplifier and if the offsets exceed ±2V, Q7 is turned off which turns off QB and the normally-on relay. Thus, the loudspeakers are protected from any DC voltage produced by fault conditions in the amplifier. Diodes DZ & D5, together with Q4, provide a mains voltage monitor. As soon as the AC input voltage disappears, as when the amplifier is turned off, Q4 turns off and turns on Q5. This turns off Q7, Q8 and the relay. Hence, the loudspeakers are disconnected immediately the amplifier is turned off and thereby any switch-off thumps are prevented. Q6 provides the turn-on delay by means of the 2.2µF capacitor at its base. At switch-on, this capacitor takes about three seconds to charge via the base of Q6. This turns on Q6 which keeps Q7 and Q8 off. When the 2.2µF capacitor stops Courtesy & headlight delays for cars These circuits use one common 74C14 IC to perform two functions: courtesy light delay (ICla, lb & le) and headlight timer (IC1d, le & 1f). The courtesy light delay enables the driver and passengers to close the doors while still having the interior light on for about 15 seconds - ie, enough time to fix seatbelts, put the key in the ignition lock and stow handbags and such. The headlight timer gives a simi66 SILICON CHIP 10k 47k 2.2 I +1sv-41---+-<1Nlllr----+-t REG RL1 06 1N4001 .,. .,., .,. I PROTECTION I RELAY / POWER ON DELAY I AMPLIFIER TRANSFORMER I e -=- I I ~v---~02 I I I I MAINS OFF DETECTOR 03 BC548 I I I I 6.8I ~ 47 47 k k .,. OFrSET OETEcioR .----.----+-------------1 FROM POWER /1- ~ ~L -: AM:_IFl.,ER-S---+---------------------' / 4-J TO ·~~ charging, Q6 turns off, Q7 and QB turn on and the relay connects the speakers. When the power is turned off, diode D6 discharges the 2.2µF capacitor so that it is ready for the next turn-on cycle. Don Paton, Glen Waverley, Vic. ($30) lar benefit at the end of the journey and enables the headlights to be left on for 15 seconds or so after locking the car. This can be convenient for walking down a driveway and so on. The courtesy light delay works as follows. When a door is opened, the 22µF capacitor at pin 11 of IC1b quickly charges via the 1.5kQ resistor, hence IC1b's output goes low and IC1c's output goes high, turning on Ql and relay RLY1. When the door is closed, the 22µF capacitor discharges via the associated 560kQ resistor and thus holds the relay on for about 15 seconds. If the parking lights (or the headlights) are turned on, pin 9 onc1c is pulled high via a 10:kn resistor which causes its output lo go low, turning off transistor Q1 and 'relay R-LY1. The headlight timer circuit (IC1d-IC1f & Q2) works in exactly the same way except that two pushbutton switches (S2 & S3) are~used to start and stop the timing sequence. S. Lambie, Mt. Waverley, Vic. ($25) 311CDCODED COMMON ANODE DISPLAY SIIIITr.NJ~ COM I $1 112 \:!.I 4 I"::'\ \;.!/ 101 1G2 ·- • d 111' g ,._ I I 05-01 \;.!/ I"::'\ - \;,:./ 1 128 I"::'\ \;,!I 21 .4 \:!.I u.. 5 !!.,_ 9 Gi t:;"\ \;,:./ Dt•D12 t:;'\ 411N4141 SS 111' 27 I"::'\ IC1 ICM7217UI 15 SELECTS5 I 24 r.'\ \:!.I 21 ~· 16 2 IT .0471 100 = I"::'\ ~2 ... 01 2N2907 02 2N2907 --«- ,.:;I ) \.!:: .,__ \;.!/ 1811 10k 4.711 ,... This simple circuit will select a number from 1 up to a maximum preset value of 999 and is ideally suited for use by social clubs running many raffles with varying numbers of tickets sold. The circuit is based on a 7217 IC l!..£-120 +liV RESET,◄ S4 Chocolate wheel with fixable numbers 17 I 7 11 \;,:./ 1 •LJc I"::'\411 N4141 4 er C I co- S2 101 1f...J....fb t:;"\ \;.!/ \;,:./ b I I"::'\ 1 I I 01-04 t:;'\4l1N4141 ·IL- ~ which is a CMOS 4-digit presettable up/down counter. This has an onboard oscillator (pin 13) and a presettable register which is continually compared to the counter. At power up, the counter is set to 0000 and pin 2 goes low and turns on Ql. This pulls pin 12 high and loads the counter with the number selected via the thumbwheel BCD switches. PARK LIGHTS ------ ♦12V The number selected is displayed on the 7-segment LED displays. Counting is inhibited during reset and load operations. The counter counts down from the number selected to zero whereby pin 2 goes low again, turning on Ql, which pulls pin 12 high again and reloads the counter. This sequence continues until the select button S5 is released. A number between 1 and the thumb-wheel selection will then appear on the display with all leading zeros supINTERIOR pressed. The circuit LIGHT runs at lOkHz so that, when counting is enabled, all figures appear as 8s with no possibility of visually determining when to stop. This ensures a random draw. The circuit is powered from a 6V rail made up by four "C" batteries. Grant Schultz, Rostrevor, SA. ($30) 7+12V STAIITI S2 1. .,. .,. ]UNE 1992 67 VIDEO SWITCHER FOR CAMCORDERS & VCRs Solve your problems with dubbing from your camcorder to your VCR with this 3-way video switcher. It will allow you to dub from any one of three video sources and to watch any of them on your video monitor. By JOHN CLARKE Do you need to copy old Beta video tapes to a VHS machine or perhaps from your Video 8 camcorder to your VCR. Or do you just have two or three VCRs and need to watch and dub tapes between them? If you experience any of these situations, you will be fully aware of just how much of hassle it is to disconnect and reconnect all those leads. Wouldn't it be much more convenient to leave your VCRs and video monitor permanently connected to one video switch box 68 SILICON CHIP and then be able to watch any machine or dub from it at will? The solution is the Video Switcher presented here. Fig. l shows how the Video Switcher is used. The video input, video output and the audio inputs and outputs from each video recorder or camcorder connect to the video switcher. Monitoring of source 1, source 2 or source 3 is selected via the front panel Monitor switch. This enables you to watch the selected VCR on a high quality video monitor and listen either via the monitor's internal audio speakers or via a stereo system. If you don't have a video monitor, you would simply connect the modulated RF output from the Video Switcher to the antenna terminals -just as you would with a single VCR. Copying between sources is selected with the Dubbing switch. This allows dubbing from any video source to either one or both of the other machines. Note that all the VCRs may have mono, stereo or hifi stereo outputs. The Video Switcher is housed in a standard plastic instrument case measuring 260 x 84 x 190mm. On the front panel are the Monitor and Dubbing rotary switches plus the power switch. It is powered from an AC plugpack. At the rear are all the RCA sockets necessary for the audio and video inputs and outputs of three stereo VCRs and/or camcorders. In addition, there are audio and video outputs (which connect to a monitor) and a modulated RF output socket. All told, there are 22 RCA sockets plus a socket for the 12VAC power input. Inside the Video Switcher is quite a large PC board but most of the circuit components are very cheap and readily available. Most of the project cost will be made up of hardware items rather than circuit components. How it works The complete circuit is shown in Fig.2 and uses eight ICs and 16 transistors but is fairly simple and repetitive. For instance, six of the ICs are 4066 CMOS analog switches which simply do the job of switching the signals to their relevant destinations. Again, there are four video buffers which are all exactly the same circuit. The 2-page circuit can be divided into two distinct audio and video sections. The lefthand page contains the video section and RF modulator, while the righthand page is the audio section and power supply. Let's look at the righthand page of the circuit first. At the top you will see the three left channel audio inputs which are AC-coupled via 4.7µF bipolar capacitors. Below these are three right channel audio inputs with the same AC coupling. These are switched using two poles of the Monitor switch; S2b and S2c for the left 1 VIDEO RECORDER VIDEO OUT IN 2 VIDEO RECORDER AUDIO OUT IN L R L R VIDEO OUT IN 3 CAMCORDER AUDIO OUT IN L R L R VIDEO OUT IN MONITOR SOURCE 1 SOURCE 2 SOURCE 3 DUBBING 1-2, 1-3, 1-2+3 2-1 , 2-3, 2-1+3 3-1, 3-2. 3-1+2 AUDIO OUT IN L R L R VIDEO+ AUDIO MONITOR OR RF SIGNAL OUT TVOR VIDEO MONITOR VIDEO SWITCHER Fig.1: block diagram of the Video Switcher. The unit is capable of switching up to three video sources with stereo audio channels & features video, audio and modulated RF outputs for connection to a monitor or TV set. and right channels respectively. The left and right monitor outputs are mixed via two 4. 7kQ resistors and AC-coupled via a 10µF capacitor to the audio input of the RF modulator. Video monitoring Video inputs 1, 2 & 3 (top lefthand corner of the circuit) are loaded with 75Q resistors and AC-coupled to the CMOS analog switches of IC4 (bottom lefthand corner). The control inputs of the CMOS switches, at pins 6, 12 & 5 are all tied to the -8V supply via 1 0kQ resistors. One pole of the Monitor switch, S2a, selects a video input by pulling the particular CMOS switch control input high; ie, to +8V. The three switch outputs (pins 9, 10 & 4) are connected together and thence to a video buffer circuit (video buffer 0). This comprises four transistors and five resistors. Each tran- Main Features • Switches up to three video sources • Video plus stereo audio switching • Monitor any 1 of 3 sources • Video and audio plus RF monitor outputs • Dubbing available between any sources Fig.2 (following page): the circuit uses ► CMOS analog switches (IC1-IC6) to switch the various audio & video inputs. Op amps IC7 & IC8 buffer the audio outputs, while transistors QlQ16 provide high-impedance buffering for the video output signals. The rear panel carries 22 RCA sockets for the video & audio inputfoutput connections plus a socket for the DC supply. JUNE 1992 69 VIDEO DUBBING IC5b - 3 t 4 4-1 VIDEO 470 OUTPUT 470 ,...._ VIDEO BUFFER 3 16VW 16VW ~ l-4F-=lf..:...o IC6d - 11 10 013-016 ~+8V I 91 ~ 18· " ~ ,...._ - 4066 IC5a · 1~2 4 3 4-J +BV t- t-- . VIDEO BUFFER 1 16VW 16VW ~ f-:IF-=IF..:-o 05-08 I ... I I 10k _6 VIDEO 470 OUTPUT 470 '~ 1N~74s© - ~ I T I -8v-r 8 ~ 16VW 16VW ~F-=IF..:-o 09-012 4066 IC6a 1r:::'12 --9 DB 1~ 1N4148 • VIDEO BUFFER 2 -8V ~ + 8 V 13 S3: DUBBING 1 : 1-2+3 2: 1-3 3 . 1-2 4 2-1+3 5 . 2-3 6 2-1 7: 3-1+2 8: 3-2 9: 3-1 -7 VIDEO 470 OUTPUT 470 t 10k ► 10k BV 1N~f48$ -5 S3 1N~~48~ _4 - r) I. _3 - D4i(f) 1N4148 ,l-~------ - +BV 470 16VW - - - - - - - - -, IC4b ,,/ ( //"" 0.1I I 8V 10k 1 v~_2 S2a , ) 3 -BV I I --lj1.0¥,0r"""l..... Lr,r1 -BV 10k: .,. r~~__!."4-~-P-+--~: IC4c 11r':::::"110 r -8v- 4066 3I ~ ,4 t "I" ~.sv '7s I I I I ---..... 03 10k BI?~ 01 - - - - i - _ _ ; ......... BCSSB E ~E sr.:: J '-=>c ,;J'-;---1---+-, VIDEO BUFFER 0 SILICON CHIP 0.,.r•~ I I I TI 470 16VW 1k ---...:f-~YoN\-<i,--, I I I I 4.7k ·:1· AUDIO IN VIDEO IN UM1285AUS0/1 (+SV) HL-RM-TS3/4AU .(+6V) + RF IMODULATOR I ' : ~ - - - - - - - - .,._ - - - J ~ 16VW +SV I I I B~~) 04 C BC328 10k -'t ~--------.•:F-=l■Lf'-----1-0 I I /?E 02 E BC548 .....----:l------::+-1 11 70 2.2n 2.2n .__.....,B,....1_~-1..._ 1 10k - BV BC338 VIDEO MONITOR OUTPUT 470 16VW VIDEO SWITCHER RF □ MONITOR OUTPUT AUDIO INPUT 1 LEFT ~p AUDIO INPUT 2 LEFT 4.7 10 4.7 ,7 B~ 47k .,. 4.7 -BV 47k ~p AUDIO INPUT 3 LEFT AUDIO 'OUTPUT 3 ' LEFT -BV .,. +BV .,. 4.7 4.7 AUDIO OUTPUT 2 LEFT •~ ~p BP ~ S2: MONITOR 4.7 1 : SOURCE 1 2: SOURCE 2 3: SOURCE 3 AUDIO OUTPUT 1 LEFT BP -BV 47t . .,. 47k 4.7k ~ MONITOR AUDIO .,. +BV -BV LEFT •~ ~ 47k .,. +BV AUDIO DUBBING OUTPUTS AUDIO 'NPUT 1 RIGHT (rip AUDIO INPUT 2 RIGHT 4.7 AUDIO OUTPUT 3 RIGHT B~ 47k .,. (rip AUDIO INPUT 3 RIGHT ! 4066 IC1a 4.7 4.7 47k .,. .,. (rip 4.7 4.7 AUDIO OUTPUT 2 RIGHT B~ 47k .,. 47k 4.7k -BV .,. ~ MONITpR AUDIO RIGHT 4.7 AUDIO OUTPUT 1 RIGHT 14 B~ +5V +6V .,. POWER 47k 10 + 16VW+ ~ 12VAC FROM PLUG-PACK 02 8 +BV POWER LE01 1 16VW + 1 16VW + 1 _ 16VW EOc VIEWED FROM BELOW + - ,. -sv ~K ,A ffi ffi IG0 GI 0 JUNE 1992 71 AL TRON/CS 24 HOUR EXPRESS DELIVERY 'Our customers are often amazed at the speed and efficiency of our Jetservice Courier delivery. Phone your order Toll Free 008 999 007 and presto we can deliver your order next working day (country areas 24-48 hours later). Our famous 14 day satisfaction money back guarantee protects your hard earned $$$'s should ever a purchase be unsuitable for your needs. I invite you to try Australia's best electronics phone order service soon.'Regards, Jack O'Donnell Get 240V AC from 12V DC! Great for camping, on the farm. boats etc. The All New Powerhouse 1200W Inverter 1"c1u ,oo '4 (EA Feb '92) This new design of Power Inverter will provide 1200 Watts of power from a heavy duty 12 or 24V battery. Using the latest Mosfet output stage and toroidal transformer this inverter is efficient and will deliver high surge currents . The Powerhouse has been designed not only for rugged bullet proof operation but for ease of construction, two PCB's hold all circuitry with one inter-connecting cable. (7 wires) . Thi• kit come• to you In • fully drllled, pre punched ch1111t1 complete with ollk ocrHned front panel. A11embly of the kit to otmplllled ao the majority of component• mount on a olngle PCB. Thuo vlrtually ellmtnatlng all Hternal termlnalo. Suitable for uoeo In camping, boating, llohtng, mining, remote Hlllemento etc. Feature,: • Massive 1200W continuous 2400W surge will run almost anything• 12 or 24V operation selected via internal wiring • Low battery cut-out • Over temp cutout • Circuit breaker for overload protection • Auto start circuitry for standby operation • Easy to construct Comeact 40 Watt Inverter Recharge Your Mobile Phone, or Run Your Electric Shaver from $79 the Car Battery! ~, .OO This fantastic little unit is ideal for use with (SC Feb ' 2) "'-.... __ !Jlil!!!f ~.w.l'T ~1:RTER [ 4 . ... I• i -- ~ ~ I II\ ___), ~ 1 , --==----- incandescent globes, (note this model inverter will not run fluorescent lighting) electric shavers, small radios and some plug pa.ck operated devices, ie charging cordless dnlls and other rechargeatle battery appliances etc. Feature,: • Operates off 12V DC • Battery connection leads provided • Light weight • Uses Mosfet devices • High efficiency • Low heat dissapation ~hannel Guitar Mixer and Preamp ~ c ":ran 19 92) This un it features separate bass, midrange and treble controls, very low noise and distortion, separate input level controls plus an output level control. Ideal for use with most musical instruments from keyboards to guitars to tape decks . In fact, you can feed it with just about an y audio signal - it's not just lim ited to guitar outputs. • Dlatortlon: (at 1kHz and 100mV input) less than 0.0075% cil!II • Frequency Responoe: 18Hz35kHz (+/ -3dB) . The kit includes PC Board, potenticmetres, input sockets and al I specified components. The kit does not include the optional ground plane, K S535 $49.95 nor the 15V power supply board . .,,r K 6790 Kit Version $799.oo K 6792 Fully Built & Tested 12V Input $ 9 9 9 K 6793 Fully Bui lt & Tested 24V Input .00 Adjustable 0-45V, 8 Amp Bench Power Supply (SC Jan/ Feb '92) K 3360 $375 .00 Using state of the art circuitry this supply will be a great asset to the enthusiast and professional alike. It uses switch mode principles which allows for smaller transformers, and heatsinking which means greater efficiency, less heat and lighter weight. Feature,: • Variable output• Variable cu rrent limit• Separate Earth Terminal • Individual Volt and Amp Meters• Constant 13.8V setting • Short circ uit proof Speclflcallono: • Output voltage 0-45V • Output current SA <at> 35V, 6A <at> 40V • Load regu lation 1% • Ripple and Noise 40mVp-p at SA 35V • Current limit 800mA8.6A • Over current limit 9A • Foldback current less than 2A 3-50 Volta at up to 5 Amp• This supply has been one of our most popular. It includes the latest refinements and is now housed in a tough 'ABS' instrument case. This compact version uses a , high efficiency toroidal transformer resulting in less heat and weight. • Exclusive to Altronlc• • Delu xe i nstrument case • Attractive silk screened front panel • Pre-drilled and punched chassis - No holes to drill • Front panel drilled for K 3302 option. Speclflcatlono: • Output Voltage: 3 to 50V • Output Current: 5 Amps Max • Floating Output • Ripple: Less than SmV • Dual Meters Just Arrived Digital Altimeter ~ Polyswitchesl 10 Turn Pot For Precision Voltage Control Option K 3301 $4.50 for Gliders ·,r,v ." '.i>\ll ~ .• ~ " These oevices provide Fixed +/ -12V Rails lndependant of Main Output K 3302 $14.50 ! excellent protection and Ultralights .-l -=-~~--__:. for your speaker (SC Sep/ Oct '91) ~~--~~~system . They simply connect in series between your ~ This compact digita! altimeter · amp and speaker . When the current exceeds the Diaital Voice Recorder can display altitude up to 19,990 feet with 10 feet polyswitch rating they go open circuit, thus protecting r• r.,,,;--~ * resolut ion. Accurate to better than 3.5 percent. A must for hang-gliders , ultralights etc. Operates on 9V battery. K 2580 $299 .00 Here's a simple project that monitors the power drawn from a ·master' socket and 95 automatically switches on a 'slave' socket . It is versatile, because it can monitor one or several appliances Amplifier ! plugged into the 'master' and switch on one or several devices plugged into the 'slave'. Ideal for H i-Fi 's or computers with peripheral hardware . your expensive investment. R 4050 For Tweeters up to 100 watts. 0.5 amp at SOV $6.20 ea R 4055 For Midrange/ Woofers up to 100 watts. 1.15 amp at SOV $6.95 ea R 4060 For Complete System up to 200 watts. 2.45 amp at 50V $8.90 ea ':::•Ml( $149.oo 11:Y~ -;,,. I J,. ! t-!~ Thi• Dlgltal Recorder dellvero a1tonl1hlng reproduction of voice and/ or music without any '.!Jg~~,, rci'l~ital voice recorder that can store 4 $ 59. K 4360 $49.50 Deafening 110db Modulated Tone Now our top selling Car Alarm Kit. Two Sensor inputs - Normally open and normally closed enable simple connection to door, bonnet, boot light, switches etc. different signals, voice, sound or a music source of up to 30 seconds each or one recording of up to 2 minutes . Typical appllcallono Include: • Alarm system messages • Sales messages for customers put 'o n hold ' • Experimental telephone answering machine • Door Station announcer• Talking displays for shops • Emergency warning message announcement • Operation instructor for ma~hinery etc_• _Countl_ess other applications where voice or music Is required • $100's cheaper than imported digital recorders• Includes Instrument case and all components. (SC June/July '91) Make your atage production a r,rofaaalonal I/low with Ihle new Lighting M xer. Ideal for amateur thHlre groupe band• .tc. 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. It has been designed and built for the rigours of commercial use. You can flash each channel up to any brightness as set by the 'Flash Master' fader. Similarly, the 'Channel Master' control fades all lights up or down, to or from their individual fade settings. Two chaser faders control the rate and lamp brilliance when the unit is operated in chaser mode. The lights can be flashed to full brilliance or to an intermediate setting as set by the 'Chaser Master' fader. K 5815 NORMALLY $~.00, THIS MONTH $2~9._oo 5510 $19.s5 Surround Sound Decoder K 5585 $39.95 (E.A. Jan '92) Build this new surround sound processor and envelope yourself with the stunning realism and dramatic sound impact available from surround-encoded videos or TV transmissions. It can also enhance conventional stereo, by providing a rear or ·ambiance' channel. SOW Mosfet Module 50 Watts RMS into 8 Ohms. This great module features moderate power output at low harmonic distortion. Simple to build and compact in size this unit makes a great replacement module for your old Hi-Fi or buy two and make your own stereo amplfier. K his great new kit enables you to ustomize your sound system in our car or at home. The circuit imply connects between the aud ource and the amplifiers. There re two outputs, one for bass nd another provides signal forth equency range (i.e. one for bass, assive crossover is required in the speaker on n + and -15V rails. The result is much betters 0-30V Power Supply 5115 $49.95 Hi Syste (SC May '88) Stereo 50 + 50 Watt Midi-Style Amplifier_ Replace That Old Beaten Up Amp! (SC Feb and March '92) ~ W,~tlril9'>~ ,v,o d /~ ~ ~ ,... -~ ' = "'»'! :~' .y,..-,., ~ :: - • This fantastic new amp has all the features of commercial units costing hundreds of dollars more using tip 142/147 transistors it is capable of producing a total of 50 Watts per c hannel RMS. Into 8 Ohms makes an ideal replacement midi unit. Performance: Output Power: SSW into 8 Ohms, 80 watts into 4 Ohms Harmonic dlotortlon: less than 20Hz to 20kHz Featur • Variable Output • Short Circuit Protected • Full 1 Amp Available • Variable Current Limit • Separate Earth Terminals • Dual Scale Meter • 3-30V to 1 Amp Max with Variable Current Limit • Output Current: o to 1 amp • Load Regulation: 0.2% Max • Output Ripple: 2mV RMS Max. This "state of the art" electronic ignition system uses the same semi-conductors as found in modern motor cars. Extends the life of plugs and points. Increases power and improves fuel economy . Compatible for 4, 6 and 8 cylinder engines. Install one into your car and start saving$$$ from the very first day . 5045 $299 .00 4015 $58.50 --..--. . . . . . . . . .=---.. . --.. . - -----,.. .-arm ----,-----,, Flush/Surface Mount Alarm New . High-Tech Panel K K With stylish compact good looks this alarm smoothly into any residential or office decorblends by either flush mounting into the wall, or surface mount. 3 sectors include 24 hour panic / fire, perimeter and internal which can be isolated enabling the alarm to be armed at night with occupants inside whilst still protecting entries. simple 4 digit access code for operation . See Altronics '92 catalogue for full details. '■i-,-,-,~---,-=~=-=-=-,-,-!-.-!-=-=-!-= ----, 1 1 3 5 6 8 9 # s 5490 $-v,efoo This Month $99.oo Alarm Power Supply This amazing new model features just about everything you could imagine! Multifunction keyring remote control will arm and disarm alarm (and activate central locking if fitted), chirp the horn, turn on car headlights, panic and even open the boot (if actuator fitted). One remote can control two alarms. Other features include: Starter inhibit, valet mode, central locking interface, flashes car indicators when tripped, auto reset plus much more! s s230 t249.oo ••","t",,'!'ll.,"4!114'!'1!'.!all,~,~~,•4•,'!'llt";"l!"••4•;"t"tl!l11"J~ S 5231 replacement Remote Control $48.50 This UPS (Uninterruptable Power Supply) will supply 12V at 1.2 Amps via its internal inbuilt sealed lead acid battery even when the mains has failed. Ideal for use with alarm system power supplies monitoring systems, warning systems etc. Satellite Siren This self contained compact unit can deliver a massive 120d8. It connects via 3 wires to any alarm system that has an output that is normally negative. Will sound if the wires are cut. Arm/ disarm inbuilt key switch. 9090 $69.95 S 5235 $6_;34s Intro Price $55.95 UHF Microprocessor Controlled Wireless Security System M Apart from the flawl&ss operation of the system one of the great features is its application with rented or leased premises - let's face it, money spent on installing a wired system in your home or office, factory , etc is irrevocably lost when you move on. With this system you simply take it with you. Ultra high-tech and push button operation makes this unit a breeze to install and operate. Features 6 sectors plus 2 x 24 hour fire and tamper circuits. The S system includes main controller, 1 Passive Infra Red Movement Detector, 1 window or door Reed switch, wired siren , power supply, back-up rechargeable battery, and a special personal remote. All sensors are radio transmitters which means no wiring is neccessary (except for the plug pack and siren) . The whole system is coded so it can not be interfered with and can be changed any time by the owner. Each individual sensor can be easily set to operate on any sector. The main controller utilizes latest EEPROM technology which means things like . selecting user on/ off codes, isolating sectors are a breeze. Includes a myriad of other amazing features , too many to mention . Wireless Remote Keypad Call AL TRON/CS today fo r a frH colour brouchure. ~ 1 complete 1y1tem lncludeo: External Siren S $1_.,u.00 1 x Control Panel Now $114.95 2015 $1 1 x Passive Infra Red Detector/ Transmitter C 1 x Door/ Window reed Switch/ Transmitter 1 x Hand Held remote Control/ Transmitter 1 x Horn Speaker - 10 watVwired 1 x 240V AC adaptor 1 x 1.2Ah Back-up Battery 1 x Set of batteries for all transmitterR Complete System Door/ Window Reed 5240 5255 s 5240 NOW O NLY $579.oo Switch & Transmitter S5247$~ Now$63.9 De-Soldering Iron Drawers Unique design allows units to be 'dove-tailed' together. Drawers _ _ -~--.: _ will not stick or seize . Single or - , ~ . ·_ :J double drawers available. 001 c\'I\ ·'· J ~ <Ja so~1.,. eer -, ·· ~ ..· H 0235 Single .95 ea 1\'I ~11/J I : 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. 240VAC 30W. Earthed. . Simple cleaning action. $4 $5 .50 ea H 0238 Doable ,,,-~ · ·- -l This Month $ 3 9 .95 . _,,_,,,.,. . ~ . .:_< ·_ . .. · · ·. ·. · -., ____2')11;___ ·· .. . · -· ._ . T 1255 Replacement 1.5mm T!P $4.95 T 1252 Replacement 1.2mm Tip $4.95 - Micron Mk II Soldering Station These cases have generous ventilation slots on both the top and bottom panels, a myriad of mounting posts are provided for PCB's and 'extra tough' mounting posts are included for securing transformers. Massive size: 355 x 250 x 122 mm. Thll Month Only H 0490 Grey Case NORMALLY H 0491 Black Case H 0492 Blue Case $~ea A 1000 $69.95 .. os IT Universal Remote Control This universal infra-red remote control makes all other remote units superfluous. Will control CD players , videos, TV's and stereos etc. Controls up to 6 different appliances. Easy to use and programme from an existing functional remote. - $45 .00 Winner ol the Taiwan Good De1lgn Award Now you can solder anywhere with this new gas soldering iron. Features • See through gas chamber (no more guessing how muc~ gas is left!)• Built in ignition cap• Uses standard butane gas• Comes with safety bench stand • Supplied with 2mm soldering tip and blow torch tip • Adjustable temperature from 400' C to 1200°C • Can be easily refilled with standard butane lighter gas• Replacement tips are less than half price of some other brands! REPLACEMENT TIPS • ALL $4.95 ea 2455 Replacement Exhaust Port T 2451 Replacement 1mm Conical Tip T 2456 Hot Knife Tip T 2452 Replacement 2mm Conical Tip T 2457 Hot Blower Tip T 2453 Replacement 3mm Conical Tip T 2458 Blow Torch Tip T 2454 Replacement 3mm Chisel Tip T 2448 Weller Butane Gas Refill $5.95 - Screwdriver tern perature adjustable between 2500C and 450°C enabling very delicate soldering on low settings with surprising heat energy reserve on maximum setting. Relative temperature is indicated by LED lamp brightness. Now u1e1 ,tale ol the art ceramic heating element. T 2446 Normally $ ~ 5 Two way printer/ peripheral computer switch with D25 sockets. Allows two printers to be run off one computer and individually selected or allows one printer to be run off two computers and individually selected. NEW D 1570 Normally $;<at>'95 FOR '92 This Month $39.95 .· All New IRODA Gas Soldering Iron Temperature Adjustable Soldering Iron A/8 Computer Switch Box T 1250 $29.95ea Electronic Temperature Controlled, Temperature Selectable, Soldering Station. The MICRON T 2440 soldering station offers the ultimate in controlled temperature hand soldering. Featurea: • Variable Temperature Control • LED Temperature Readout• Zero Voltage Switching protects CMOS Devices • Grounded Tip • 48 Watt Element • Thermocouple lmbedded in Heating Element for Precise Temperature Control • 24V Low Voltage Element• Rubber Silicon Lead • Chrome Plated, Iron Clad Ultra Long Life Tips• New Improved Ceramic Element $139 T 2440 Normally $%s5 , This Month Only .95 Massive Savings On Old Style Rack Cases AM/FM PLL Tuner - I 1"':J l:?: .,,.,..,. '!c ~ ; o . ... ith the introduction of our new range of rack cases, we have sacrificed the old tock at below cost! This means fantastic savings for you - our valued customer. lease note stocks are limited - no back orders. Unit - All $25 0404 Grey T Unit - All $30 o RRY F~or-.4 Unit - All $35 °• 0405 Grey S0402 Silver Anodised 0 i . .. . . S0403 Silver Anodised 0413 Black Powdercoat 0406 Grey P a110 $289.oo Save your precious and expensive computer hardware and hi fi etc f~om t~e power surges, spikes and lighting. A must for anyone who doesn't want their equipment blown up! New 8 way model contains two power filters. 300 Watt Inverter TURN 12V DC TO 240V AC . This fantastic inverter will power lights, TV's, tools, electric shavers and a whole host of other appliances. Great for camping, out in the bush and any place where 240V is not available. Features: • Complete with over current circuit breaker• Fused 240V output• Built in panel meter to monitor output voltage • Strong steel case and chassis. A 2210 Normally $ ~.00 This Month $199.oo _, -- - :_3 ~ ~- .:...::.... Replace that old Dial Tuner! Thi• 1tereo amp 11 Ideal for background/loreground appllcatlon1. Fantaatlc !or re1tauranll, 1hop1, dl1eo'1, aerobic•, PA 1ound 1y1tem1 and home. • 90 watts RMS per channel minimum into 8 Ohms from 20 to 20,000Hz with less than 0.05% THD • 2 large power meter indicators• EIA Panel with handle device• XLR socket for speaker terminal • Output relay to eliminate turn-on and off transients • Dimensions: (W x H x D) 482 x 92 x 295mm • Weight: 10.5kgs • Ideally suited to A 2210 stereo tuner. A 2040 ~ o This Month .00 These amazing little speakers will impress you and your friends. Carbon Fibre is a new high tech material from which these speaker cones are made. Complimented with Barrium ferrite magnets the results are simply amazing. 8 and 16 ohm versions available makes multi speaker installations a breeze. Weatherproof design makes them ideal for car doors and boats! C 0641 8 Ohm C 0643 16 Ohm T SO% 0 Normally $~95 save Up $25.oo or $40.oo pr - I _- • Thl1 fantaallc tuner la the Ideal add-on to any 10und 1yItem. Can be u1ed aa background mullc 10urce In reataurant1, lhopa ate or any PA application. Al10 a great upgrade !or the home HI-FI. Featurea: • Digital LED frequency readout display • FET FM front end for high image rejection • Phase-linear ceramic filters are incorporated in both AM and FM IF section• Phase-lock loop (PLL) IC for FM multiplex stage• Dimensions: (W x H x D) 435 x 60 x 232mm • Weight: 3kgs. 100mm Super Carbon Fibre Speakers This Month ,.._,,_<,.,.,.,. __ $",.,,,r $539 Our Top Selling 17 Range Digital Multimeter for an Amazing $39.95 With quality and features you would expect only on expensive meters the Q 1056 represents excellent value for money. Speclflcatlona: • DC Voltage: Ranges 2-2000V AC Voltage: Ranges 200V, SO0V DC Current: Ranges 200mA, to 10A Real1tance: 5 Ranges 200 Ohm, to 2M Ohm Diode Teat: Test Current 1.0mA Test Voltage 3.2V Max Battery Teat: Ranges 1.5V, 9V Loaded Current: 1.5V 100mA, 9V 6mA Q 1058 Normally ~ 9 5 This Month $39.95 Q 1057 Carry Case to Suit $12.50 ~~o~ CB Type Mlc • . . . • High performance noise !'ttenuating pa'/ earphones• Noise cancelling >f,j 'rl'i 1v1or0 · microphone • Cushioned head pad• 0r, Super sturdy • Great performance • ·• Superb, professional pilot's headset will Awarded the Good Product Design Award for CETDC in 1987. This fantastic last a lifetime with reasonable treatment Ultrasonic Cleaner can earn Fantastic new model includes many than before. Over 2000 already sold Australia wide. Computer Connectors, PCB's, Switches, Relays, Jewellery, Glasses, Watches A 0100 Normally $~00 etc. This Month Only $ 1 7 5 .oo 12V DC Computer Fan New model just arrived! 80 x 80 x 25mm. Ideal for amps, power supplies, computers and just about anything else that requires effective cooling. Exceptional value for money. F105o$17.so These models consist of only high quality wire connection . 2 Way, 80 Watts RMS Crossover Frequency: 3.5kHz dB/ Octave: 6dB c 4005 $11.95 2 Way, 150 Watts RMS c 4007 $26.95 3 Way, 80 Watts RMS Crossover Frequency: 600-800Hz/5kHz dB/Octave: 6dB c 4006 $20.95 3 Way, 150 Watts RMS Complete with appr1;>x 1.Sm , curley cord .. Fantastic_ for CB s, ,,--:: J amateur radio enthusiasts etc. C 9070 $189 .00 Car Voltage Adaptor This handy unit simply plugs into your car's cigarette lighter socket and presto' Gives you switchable 3, 4.5, 6, 7.5, 9 and 12V DC at up to 800mA. Includes a range of output plugs. Reversable polarity. Great for pocket TV's, radios, portable CDs etc . Simply brilliant Mylar stereo headsets and dynamic mic combination. M 9150 $16.95 Speaker Speclllcatlona: 20Hz20,000Hz, 32 Ohm, 3.5mm stereo jack, 6.35mm stereo jack adaptor. Microphone Speca: Dynamic type, 300 Ohm, 100 Hz15,000Hz -80db <at> 1 Khz, c 9055 $44.95 3.5mm Mono Jack Portable PIR Alarm Casio Two Colour Printing Calculator I •n. ,~ - * Crossover Frequency: 3.5kHz dB/Octave: 12dB ;, Stereo Headphones with Dynamic Mic components. PCB mounted quick connectors for easy and reliable • . New stylist model, with simple one handed operation. _Uses standard button mounting. :,~ - ' C 0335 $ 2 7 95 ,:... · _ _ _ _ _ _.,..,._ _______ cable, allowingNow evenbetter better performance! value for over in cleaning r · _. , improved microphone and shielded its cost a hundred times ·. ,, •. (_ • Includes standard aircraft jacks. High Performance Crossovers I Noise Cancelling Altronics Aviation Headset Pin Point Ultrasonic Cleaner • • A ready to go system, no installation required • Fully automatic operation, very user friendly • Large coverage area • Portable or wall mounted • Long life 9V battery operation (battery not included) • Battery low warning • Lightweight , compact and attractive. s 5305 $p8".oo, This Month $49.oo Wa ■ Super Heavy Duty Tripod coMPETITORS SAVE OVER pRICESI This great new model holds an amazing range of equipment. With rubber feet for sure and stable grip. Anti-sway bars on legs prevents wobbling. Adjustable height from approx 1 to 2 metres. Lightweight aluminium construction and collapsable for easy transportation. Removeable mounting plate makes this Crossover Frequency: 600-800Hz/5kHz dB/ Octave: 12dB tri-pod ideal for amplifiers, speakers, c 400& $49.95 c 0520 $129.95 lighting etc. 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 P 3310 P 3312 DB9 Male solder connector DB9 Female solder connector DB9 Male 90" PCB connector DB9 Female 90" PCB connector DB9 Male straight PCB connector DB9 Female straight PCB connector DB9 Backshell Cover DB15 Male solder connector DB15 Female solder connector DB15 Male 90° PCB connector . DB15 Female 90° PCB connector DB 15 Male straight PCB connector DB15 Female straight PCB connector DB 15 Backshel I Cover DB25 Male solder connector 0B25 Female solder connector DB25 Male 90" PCB connector DB25 Female 90" PCB connector DB25 Male straight PCB connector DB25 Female straight PCB connector DB25 Backshell Cover Spacer Screws pk 10 Spacer Screw pk 100 $ $ $ $ $ $ $ $ .. . $1.35 $1.35 $2.00 $2.00 $1.75 5 $1.75 $1.75 5 5 $1 .55 5 $1.55 50 $2.25 0 $2.25 $1.90 0 . 0 $1.90 . 0 $2.00 $1.75 .5 $1.75 $2.85 $2.65 $2.25 $2.25 $2.25 $4.45 $35.95 10 Up $1.20 $1.20 $1 .80 $1.80 $1.60 $1.60 $1.60 $1.40 $1.40 $2.00 $2.00 $1.70 $1.70 $1.80 $1.60 $1.60 $2.40 $2.40 $2.00 $2.00 $2.00 HEAVY HEAVY SERVICE -- All orders of 10Kgs or more must travel Express Road - Please allow 7 days for delivery. $12.00 to 10Kgs. $15.00 over 10Kgs. INSURANCE - As with virtually every other Australian supplier, we send goods at consignees risk. Should you require comprehensive insurance cover against loss or damage please add $'..00 per $100 of order value (minimum charge $1). When phone 174 Roe St. Perth W.A. 6000 Phone (09) 328 1599 PHONE TOLL FREE 008 999 007 MAIL ORDERS C/- P.O. Box 8350 Stirling Street PERTH W.A. 6849 ordering please rP'..IUest "Insurance". TOLL FREE PHONE ORDER - Bankcard, Visa, Mastercard Holders can phone order toll free up to 6pm Eastern Standard Time. Remember with our Overnight Jelaervlce we deliver next day. STANDARD DELIVERY & PACKING CHARGE $5.50 to 1Kg, $8 1Kg-5Kg AUSTRALIA WIDE - We process your order the day received and despatch via. Australia Post. Allow approx 9 days from day you post order to when you receive goods. OVERNIGHT JETSERVICE Up to 3Kg is $10.00, 3Kg to 5Kg is $23 .00 - We process your 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 Dealera are highlighted with a ■ These dealers generally carry a order the day received and despatch via. Overnight Jetaervlce Courier for delivery next day comprehensive range of Altronic products and kits or will order an y required item for Country areas please allow additional 24-48 hours. you. WA COUNTRY ALBANY BP Electronics ■ (098) 412681 Micro Electronics (098) 412077 BUNBURY Micro Electronics (097) 21622,' ESPERANCE Esperance Communications (090) 713344 KALGOORLIE Todays Electronics ■ (090) 215212 MANDURAH Lance Rock Retravision (09) 5351246PORT HEDLAND Ivan Tomek Electronics (091) 732531 ROCKINGHAM TV Joe's (09) 5271806 NT ALICE SPRINGS Farmer Electronics (089) 522388 DARWIN Ventronics (089) 853 622 VIC All Electronic Components (03) 6623506, TECS (03) 6706474 BORONIA Ray Cross Electronics ■ (03) 7622422 CHELTENHAM Talking Electronics (03) 5842386 COLLINGWOOD Truscott Electronics (03) 4198208 CROYDON Truscott Electronics ■ (03) 7233860 PRESTON Preston Electronics ■ (03) 4840191 COUNTRY BAIRNSDALE LH & LM Crawford (051) 525677 BALLARAT Ballarat Electronics (053) 311847 BENDIGO KC Johnson ■ (054) 411411 CRANBOURNE Mart's Electronics (059) 968200 MILDURA McWilliam Electronics (050) 236410 QLO Delsound PL ■ (07) 8396155 WEST END B.A.S. Audiotronics (07) 8447566 WOODRIDGE David Hall Electronics ■ (07) 8082777 COUNTRY GLADSTONE Gladstone Electronic Services (079) 724459, Electronic Enterprises (079) 726660 MAROOCHYDORE MALS Electronics ■ (074) 436119 MARYBOROUGH Keller Electronics (071) 214559 NAM BOUR Nambour Electronics (074) 411966 PIALBA Keller Electronics (071) 283749 ROCKHAMPTON Access Electronics (East St.) (0791 221058 TOOWOOMBA Hunts Electronics (076) 329677 TOWNS VILLE Super Solex ■ (077) 724466 SA Force Electronics ■ (08) 2125505 BRIGHTON Force Electronics ■ (08) 3770512 CHRISTIE$ BEACH Force Electronics ■ (08) 3823366 FINDON Force Electronics ■ (08) 3471188 HOLDEN HILL Force Electronics ■ (08) 2617088 LONSDALE Force Electronics ■ (08) 3260901 ENFIELD Aztronics ■ (08) 3496340 COUNTRY WHY ALLA Eyre Electronics (086) 454764 TA$ HOBART George Harvey ■ (002) 342233 LAUNCESTON George Harvey ■ (003) 316532 NSW David Reid Electronics ■ (02) 2671385 SMITHFIELD Chantronics (02) 6097218 COUNTRY COFFS HARBOUR Coffs Habour Electronics (066) 525684 NEWCASTLE Novocastrian Elect.Supplies (049) 621358 WARNER$ BAY Vilec Distributors (049) 489405 WINDSOR M & E Elect. and Communications (045) 775935 WOLLONGONG Newtek Electronics ■ (042) 271620, Vimcom Electronics (042) 284400. VIDEO MONITOR OUT • • - - - - S3 - - - ~ +SV • • • • • • Fig.3: install the parts on the PC board exactly as shown on this layout diagram. Fig.1 on the preceding pages shows the lead connections for the transistors & regulators. Be sure to use the correct transistor at each location. sistor is connected as an emitter follower and the four transistors function together as a compound complementary emitter follower; ie, as a high impedance buffer with a voltage gain close to 1. The output of the video buffer drives the video monitor output via two backto-back 470µF capacitors. This same signal is also fed to the RF modulator via a lkQ and 4. 7kQ resistiv~ divider. The specified RF modulator ·can be either a UM1285AUS0/1 which operates from a 5V supply or a HL-RMTS3/4AU type which operates from a 6V supply. Audio & video dubbing The audio dubbing circuitry uses 12 separate analog switches, in IC1, IC2 & IC3. The switches are arranged to allow selection of all dubbing possibilities for both the left and right channels. The actual switching of the 76 SILICON CHIP control inputs is done by 12-position switch S3, in conjunction with diodes D3-D8. For example, position 2 of S3 applies +8V to pin 13 ofICla and to pin 12 ofICld. This selects (dubs) the left and right channel inputs of source 1 so that they are fed to the left and right channels of output 3. All the remaining control inputs are held low via the 10kQ pulldown resistors to -8V. Position 1 of S3 applies +8V via diodes D3 and D4 to pin 13 of ICla and pin 12 ofICld for the audio CMOS switches, plus pin 5 ofIClb and pin 6 of IC1c for the video CMOS switches. This dubs source 1 to both outputs 2 and 3. All six audio outputs (three left and three right) are buffered using op amps IC7 and IC8. These op amps are set up as unity gain buffers. The video signals are dubbed using CMOS analog switches IC5 and IC6. The control inputs for these analog switches are again switched by rotary switch S3. All three video outputs are then buffered by complementary emitter follower circuits identical to that used for the video monitor output. Power for the circuit is derived from a 12VAC 500mA plugpack which feeds two halfwave rectifier circuits, comprising diodes Dl and D2 and the associated 1000µF capacitors. The plus and minus supplies then feed 3terminal regulators to provide ±8V for the audio and video buffers and the CMOS switches and either +5V or +6V for the RF modulator. Co~truction Virtually all of the circuitry for the Video Switcher is mounted on a PC board measuring 168 x 218mm (code SC02204921). The component layout is shown in Fig.3. Begin construction by checking the copper pattern of the PC board. Check for shorted or open circuit tracks and make any repairs necessary. Check also that the board will accept the mounting pins of the RCA sockets and the RF modulator. Once these checks have been made, insert all the PC stakes, links and ICs. Make sure that the ICs are oriented correctly. Be careful not to mix up the 4066 ICs with the TL074 IC. The resistors can be inserted next. These are all 1 % types and their colour codes are shown below in Table 1. We also suggest you check the value of each resistor with your digital multimeter, before it is inserted into the PC board. Now insert the diodes. Diodes D1 and D2 are 1N4002 rectifier types while D3-D8 are small signal types. Be sure to orient them correctly as shown on the overlay diagram. The transistors and regulators are mounted next. There are four types of transistors, so be sure to use the correct type at each location. Each regulator is different so again be careful when installing these. Note also that REG3 needs to be either a 7805 or 7806, depending on the type of RF modulator. Now for the capacitors. The O. lµF and bipolar electrolytic types can be mounted either way around while the normal electros must be inserted with correct polarity. The RCA sockets are supplied in banks of 2 rows and 3 wide. You should be supplied with four sets of these and one will have to be cut down to a single bank. When these are all soldered in, the RF modulator can be mounted. Front & rear panels The Dynamark labels for the fr0nt and rear case panels can now be affixed. Drill out the holes in the front PARTS LIST 1 PC board, code SC02204921, 168 x 218mm 1 Dynamark front panel label, 251 x 75mm 1 Dynamark rear panel label, 251 x75mm 1 plastic instrument case, 260 x 84 x 190mm 1 12VAC 500mA plugpack 1 2.5mm panel socket to suit plugpack 2 chassis mount RCA sockets 4 3 x 2-way PC mount RCA sockets 1 RCA line plug 1 single-pole 12-position rotary switch 1 3-pole 4-position rotary switch 2 knobs to suit above switches 1 panel mount power switch 1 5mm LED bezel 29 PC stakes 1 UM1285AUS0/1 modulator or HL-RM-TS3/4AU modulator 5 plastic cable ties 1 TL074, LF347 quad FET-input op amp (IC?) 1 7808 3-terminal regulator (REG1) 1 7908 3-terminal regulator (REG2) 1 7805 5V regulator for UM1285AUS 0/1 modulator (REG3) or 1 7806 6V regulator for HL-RM-TS3/4AU modulator 4 BC558 PNP transistors (01,05,09,013) 4 BC548 NPN transistors (02,06,010,014) 4 BC338 NPN transistors (03,07,011,015) 4 BC328 PNP transistors (04,08,012,016) 2 1N4002 1A diodes (01-02) 6 1N4148 signal diodes (03-D8) 1 5mm red LED Capacitors 2 1000µF 25VW PC electrolytic 9 470µF 16VW PC electrolytic 4 10µF 16VW PC electrolytic 15 4. 7µF bipolar electrolytic 3 1µF 16VW PC electrolytic 8 0.1 µF monolithic ceramic Wire & cable 1m twin shielded audio cable 50mm single shielded audio cable 1m black hookup wire 1m blue hookup wire 1m yellow hookup wire 200mm red hookup wire 2.5m 0.8mm tinned copper wire 100mm 75n coax cable Resistors (0.5W, 1%) 12 47kQ 1710kQ 3 4.7kQ 1 1kQ 41000 3 75g 82.2n Semiconductors 6 4066 quad analog switches (IC1-IC6) 1 TL072, LF352 dual FET-input op amp (IC8) Miscellaneous Machine screws & nuts, selftapping screws, solder. TABLE 1: RESISTOR COLOUR CODES 0 No. Value 4-Band Code (1%) 5-Band Code (1%) 0 12 47kn yellow violet orange brown yellow violet black red brown 0 17 10kQ brown black orange brown brown black black red brown 0 3 4.7kn yellow violet red brown yellow violet black brown brown 0 1 1kQ brown black red brown brown black black brown brown 0 4 100n brown black brown brown brown black black black brown 0 3 75g violet green black brown violet green black gold brown 0 8 2.2kQ red red gold brown red red black silver brown JUNE 1992 77 REAR PANEL VIDEO OUT RF OUT . . .,__ I RCA SOCKETS AC ~ INPUT -r- ~IR~ 20 ~ 22 21 75n COAX 12 14 •• 19 17 18 15 16 13 • MODULATOR 10••,, 98765432 •• • •• ••• ' f1~//j~1222 20 1 o/,/ .(; : 3:: ~,~~21 15 , ~ 1 9 17 FRONT PANEL Fig.4: use 75Q coax for the connection between the RF modulator & the RF output terminal & note that the earthy side of the plug must be soldered to the modulator's case. Take care with the wiring to switches S2 & S3. panel for two rotary switches and the LED bezel. The power switch requires a rectangular hole which can initially be drilled and then filed to shape. The rear panel requires holes for the RCA sockets and the power socket. 78 SILICON CHIP Nate that the power socket is mounted at 45° to the vertical so that it clears the video monitor socket. You will also need to drill holes so that you can secure the RCA sockets to the rear panel using screws and nuts. These sockets have integral bushes for this purpose. Wiring Follow the diagram of Fig.4 when wiring the PC board to the hardware in the case. The dubbing switch (S3) can be wired up using hookup wire but use a variety of colours so that KODFORCHIPS. .. KOD FORCHIPS. ..~FORCHIPS. .. ~ FORCHIPS... ~FORCH/PS_.~ FORCH/PS... ~ FORCH/PS. .. ~... ~ . 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D25 $114.80 Special Save $1.00 on UB11 Boxes Normally $6.95, This month ONLY $5.95· Geoff Wood Electronics Pty Ltd t ~ae~i~eo.b1~~ef;~ij~~re • output from 0.1Vpp to 20Vpp • Linear and Log sweep - 20ms to 2s (Intl or 100:1 VCF (ext) • 500/600'1 output Frequency Counter • Hfz to 100MHz • 15mV sensitivity to 60MHz • 0.1 to 1OOHz resolution • 10ms to 10s gate • 10MHz reference with 5ppm stability • 8 digit display with annunciators Digital Multimeter • 3 1/2 digit LCD • Auto/Manual ranging • Vdc, Vac,n, Ade, Aac functions • 0.5% basic accuracy • • Data Hold • Memory mode for relatiuve measurements and zeroing il's Power Supply • 3 1/2 digij voltage display • Triple output • 0 to 50V, 0.5A • 1sv 1A and 5V 2A fixed • 1mv ripple • Full overload protection Incredible value at $837 .00 Inc tax $722.00 ex tax (Inc In N s W) 229 Burns Bay Road, (Corner Beatrice Street). Lane Cove West N SW Mail Orders to - P O Box 671, Lane Cove N S W 2066 Telephone: (02) 428 4.111 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 $8.00 All prices Include Sales tax unless stated otherwise Tax exemption certificates accepted if the line value exceeds $10.00 BANKCARD, MASTERCARD, VISAf CHEQUES or CASH cheerful!~ accew;d. ~ ;:q ~ subsequent checking will be made easier. The monitor switch (SZ) has both shielded cables and hookup wires running to it. Note that the shields of the cables are terminated at the PC board ends but not at the switch. At the switch end of the cables, the shields should be cut right back to avoid any possibility of shorts. ' The video output socket is wired to the PC board with a short length of shielded audio cable. The RF modulator output connection to the rear panel RCA socket requires careful termination to avoid spurious interference on the picture. It is important to use 75Q cable and to solder the RCA plug to the RF modulator case. Once the wiring is complete, carefully check your work against the diagrams ofFig.3 and Fig.4 to ensure that everything is correct. Powering up Plug in a 12VAC plugpack and 80 SILICON CHIP switch the Video Switcher on. The ·front panel LED should light and you should immediately measure the supply voltages to the ICs. Connect the negative probe of your multimeter to ground (0V) of the circuit (the RF modulator case is suitable) and check that +8V is present at pin 14 of ICs 1-6, pin 11 ofIC7 and pin 8 ofIC8. Similarly, -8V should be present at pin 7 of ICs 1-6 and pin 4 of IC7 and IC8. Check that the RF modulator supply is either +5V or +6V, depending on the regulator chosen for REG3. Further checking of the Switcher can now be done using your video equipment. Connect the audio and video outputs of each VCR (or camcorder) to the audio and video inputs of the Switcher. Similarly, the audio and video inputs of each VCR connect to the audio and video outputs of the Switcher. Note that if you have a mono VCR, it is only necessary to connect the audio inputs and outputs to the left- Dress the leads to the rotary switches carefully & lace them together using plastic cable ties to keep the wiring tidy. The slug in the bottom centre of the modulator may need adjusting slightly for best results - see text. hand channel input and output of the Video Switcher. Monitor connection You can use either a conventional TV set or a video monitor which has audio and video inputs. If a monitor is to be used, connect the audio and video monitor outputs of the Switcher to the monitor's audio and video inputs. If a TV set is used, connect the RF output to the TV's antenna terminal. In this case, the TV will need tuning (channel 0) to obtain the best picture quality. Once everyt4ing is connected, you can check that the monitor switching is operating as it should. The picture should be clean and without a hint of =~ ~~ :;:=;:;;1 _,,..--...:-=,u ~ ::,00 0- -0 SC02204921 signals from the other sources noticeable. Problems with the picture may be caused by a faulty video buffer stage. If there are herringbone patterns in the picture when using the modulator output, you may need to slightly adjust the video slug in the modulator. In the case of the UM1285AUS modulator, the video slug is the more central one. The second slug affects the sound and should not be touched.SC JUNE 1992 81 Build this 15-watt 12-240V inverter This 15W inverter is ideal for operating lowpower AC equipment from a 12V battery. It's based on the popular 40W inverter published in · the February 1992 issue & is ideal for use with camcorder battery rechargers & telescope drives. By JOHN CLARKE & DARREN YATES The 40W inverter published in our February 1992 issue proved to be very popular, mainly because of its simple design and compact size. But, as we very quickly discovered, many people wanted an even smaller design, mainly for driving equipment like camcorder battery rechargers, power telescope drives, electric toothbrushes and the like. As it turned out, it wasn't too difficult to produce a low-power version with an output of around 15W. We did this by replacing the original 60VA transformer with a couple of 7VA PCmount units (wired in parallel). These new transformers are much smaller The completed inverter is shown here with the optional hand-held controller. This controller varies the output frequency so that the unit CiUl he used to control a telescope drive. 82 SILICON CHIP than the 60VA unit and allow the project to fit comfortably into a medium-size zippy box measuring 150 x 90 x 50mm. Apart from that, the new circuit is virtually identical to the old unit, except that we've added a power LED to give on/off indication. This LED sits at one end of the case next to a panelmount mains socket. The other end of the case carries the on/off switch and a 5-pin DIN socket that interfaces to an optional hand-held controller circuit so that the unit can be used with a telescope drive. Basically, the hand-held controller is there to vary the output frequency, to allow speed control for a telescope drive. If you don't want to drive a telescope, just leave the DIN socket & its connecting leads out and ditch the hand-held controller so that the unit functions as a conventional 15W inverter. To operate the inverter, you simply connect the power leads to the 12V battery, plug in the mains appliance and switch on. The appliance should then operate in the usual manner. Note, however, that this device cannot drive fluorescent lamps as the starting current required is too high for the circuit to produce. As can be seen from Table 1, the inverter has quite good voltage regulation and is reasonably efficient at full power. The poor efficiency at lower powers is mainly due to the use of low-cost transformers to step up the voltage to mains output. Lack of feedback voltage regulation is another contributing factor. This poor efficiency at low output powers is tolerable since the extra circuitry and cost is not warranted in a low-power design such as this. Circuit details . As the accompanying photographs show, relatively little circuitry is used in the inverter. Apart from the power transformers, it uses two inexpensive ICs, two MOSFET transistors and a few other sundry bits and pieces. Fig.1 shows the circuit details. At the core of the circuit are MOSFETs Ql and QZ which are used to drive mains transformers · Tl and TZ. These transformers are wired in parallel and each has two separate low-voltage f1 POWER 5A +12V0----0---0----- S 1 ~ - - - - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - - - , 100n Vee POWER LED1 1 1DD + 16VWJ K OUTPUT SOCKET SPEED VR1 50k LIN IC1 7555 mr .,. Vee HAND CONTROLLER ; ~ 47k DEAD TIME .,. j GDS B EOc VIEWED FROM BELOW STOP S2 COMPARATORS 15W INVERTER .,. Fig.1: the circuit uses 555 timer IC1 & transistor Q3 to provide antiphase clock signals to comparators IC2a & IC2b. These comparators then drive Mosfet transistors Qt & Q2 which in turn switch the paralleled transformer primary windings. IC2c & IC2d are the dead-time comparators (see text). windings which are connected together to form a centre-tapped primary winding. Because Ql and Q2 alternately switch the 12V supply across each half of the primary windings, the transformers produce an approximate 240V AC output across their paralleled secondaries. Ql and Q2 are switched on and off out of phase so that when Ql is on, Q2 is off and vice versa. These MOSFET transistors are Motorola MTP3055E devices which are specifically designed to switch inductive loads (such as a transformer) without the need for external transient protection. Instead, these devices each have an internal avalanche diode for transient protection and for commutating reverse voltages. We can not recommend any alternative devices to the MTP3055E, so Table 1 : Performance of Prototype Input Voltage Input Current Load Output Voltage Efficiency 13.0V 1.4A OW 272VAC 0% 12.0V 1.7A 15W 230VAC 74% 12.3V 1.8A 15W 235VAC 68% 13.0V 2A 15W 244VAC 58% do not substitute for this component. The remaining components in the circuit are there to provide the out-ofphase drive signals for Ql and Q2. ICl is a CMOS 555 timer which is set up as an oscillator operating at 50Hz. This is wired in a somewhat unconventional manner, however. Normally, the astable configuration uses a timing capacitor (on pins 6 & 2) which is charged via a resistor connected to the positive supply rail, and then discharged into pin 7. In this circuit though, the timing capacitor (0. lµF) is alternately charged and discharged by the pin 3 output via a 150kQ r!;)sistor. The circuit works like this: at switch-on, pin 3 of ICl goes high and charges the 0. lµF timing capacitor via the 150kQ resistor. When the capacitor voltage reaches 2/3Vcc (ie, 2/3 the supply rail voltage), pin 3 switches low and the capacitor discharges via the 150kQ resistor until it reaches 1/3Vcc. At this point, pin 3 switches high again and so the cycle is reJUNE 1992 83 the CMOS output. Fig.2 shows the waveforms genPIN3 erated by the major circuit IC1 sections. ov The square wave output from pin 3 of IC1 is fed to 20ms the inverting input of IC2a (pin 10) via a voltage diV · e e ~ vider consisting of two 4 7k.Q 2/3Vee resistors (one in series and PINS2,6 1/3Vee. IC1 the other to the positive supOV+--------------ply rail). The resulting waveform at pin 10 is a Vee square wave which swings 3/4Vec between the +12V supply PIN1 IC2c rail (Vee) and 1/2Vcc. ov IC2a is a comparator and its output at pin 13 goes high each time the inverting in3/4Vee put (pin 10) goes lower than PIN2 the non-inverting input (pin IC2d 11). If the non-inverting inov put is at 3/4Vcc, then IC2a's Vee output will be low when pin 10 is at Vee and high when PIN14 IC2b it is at 1/2Vcc. The open collector outov put at pin 13 has a lkQ pullup resistor and drives the gate of Ql via a lO0Q PIN13 IC2a resistor. Each time IC2a's output is pulled high, Ql OV turns on and switches the Fig.2: this diagram shows the waveforms bottom half of the transgenerated by the major circuit sections. Note former primary to ground. particularly the waveforms generated by the That takes care of the dead-time comparators (IC2c & IC2d) & how drive circuitry to Ql. We they effectively narrow the positive-going now return to ICl to see how pulses from ICZa & ICZb. the out-of-phase signal is generated to drive Q2. First, the square wave signal at pin peated indefinitely while ever power 3 of ICl is inverted using transistor is applied. Note that the output from ICl is a Q3. This inverted signal is extracted genuine square wave with almost a from the junction of the two 4 7kQ 50% duty cycle. This is because pin 3 resistors in Q3's collector circuit and, swings fully to the supply rails due to as before, swings between Vee and Vee ~ ~I ~ ~ 1/2Vcc. The inverted signal is then fed to the inverting input (pin 8) of IC2b and the output of this comparator then drives the gate of Q2. Note that the non-inverting inputs (pins 11 & 9) of IC2a and IC2b and joined together and are nominally at 3/4Vcc (we'll look more closely at this shortly). However, because the signal on pin 8 of IC2b is inverted compared to the signal on pin 10 of IC2a, the outputs from these two comparators (and thus the drive signals to Ql & Q2) are 180° out of phase. Thus, Ql & Q2 are alternately switched on and off to drive their respective halves of the transformer primary winding. At least, that's the basic scheme. In practice it's not quite as easy as that. If we simply use out-of-phase waveforms to drive the transistors as described above, both transistors will be on simultaneously for a short time at the transition points. That's because these devices take some time to change state, which means that the next transistor in the sequence will turn on before the other has had a chance to turn off. This will cause heavy transient currents to flo w in the output stage and cause overheating of the MOSFET devices. Dead time comparators To avoid this problem, we have added a "dead-time" circuit to eJlsure that both transistors are off at the transition point. Essentially, we turn the active transistor off early in the cycle and the other transistor on late. This job is performed by comparators IC2c and IC2d. These two comparators act together as a window comparator. Pin 7 of RESISTOR COLOUR CODES 0 0 0 0 0 0 0 0 0 0 84 No. Value 4-Band Code (1%) 5-Band Code (1%) 1 1 6 150kQ 100kQ 47kQ 15kQ 10kQ 8.2kQ 1.6kQ 1kQ 100Q brown green yellow brown brown black yellow brown yellow purple orange brown brown green orange brown brown black orange brown grey red red brown brown blue red brown brown black red brown brown black brown brown brown green black orange brown brown black black orange brown yellow purple black red brown brown green black red brown brown black black red brown grey red black brown brown brown blue black brown brown brown black black brown brown brown black black black brown 3 1 2 5 SILICON CHIP OUTPUT SOCKET 0 5-PIN DIN SOCKET WIRING SIDE :~~-0~ '()/ 4 3 '~ <at> ------8 A~K <. LE01 7 Fig.3: leave the 150kQ resistor (shown dotted) out of circuit & install the 5-pin DIN socket if you intend using the unit to control a telescope drive. If you just want a fixed-frequency inverter to power an appliance, install the resistor & delete the DIN socket. S1 0 IC2c is biased just below 2/3Vcc, while pin 4 of IC2d is biased just above 1/3Vcc. These reference voltages are compared with the 1/3Vcc to 2/3Vcc triangular ·waveform that appears across the 0. lµF timing capacitor on pin 2 of ICl. The result is that pin 1 of IC2c swings low just before the voltage across the timing capacitor reaches 2/3Vcc and then swings to 3/4Vcc again shortly after this point. Similarly, pin 2 of IC2d swings low just before the timing capacitor discharges to 2/3Vcc and swings the 3/4Vcc a short time later (see Fig.2) . The open collector outputs of IC2c & IC2d are tied together and connected to a voltage divider consisting of15kQ and 47kQ resistors (which produce the 3/4Vcc voltage). Thus, the corn- POWER bined outputs ofIC2c & IC2d produce brief low-going pulses which straddle the transition points of the switching waveform produced by ICl. This pulse waveform is applied to the non-inverting inputs of IC2a & IC2b and ensures that both transistors are off at the transition points. Hand controller For the variable speed drive version, the 150kQ timing resistor on pins 3 & 6 of ICl is replaced by two wires which go off to the hand-held control box. This box contains a 50kQ linear pot (VRl), a lOkQ resistor, a lO0kQ resistor which can be bypassed by momentary switch S3, and a SPST toggle switch (S2). By varying VR1, we can vary IC1's output frequency (and hence the 240VAC output frequency) from about 45Hz to 90Hz. Similarly, by pressing S3 to short out the 100kQ resistor, we can increase the frequency to about 150Hz. This makes the unit suitable for use with telescope drives and other low-powered equipment that relies on frequency for speed control. SPST switch S2 is used to start and stop the drive motor. When the switch is closed, the non-inverting inputs of IC2a & IC2b are pulled low, and so the MOSFETs (and thus the output) are switched off. Power supply Power for the circuit is derived from a 12V car battery. This supply connects directly to the centre tap of transformer T1 via a 3A fuse and power switch Sl. LED 1 and its associated 1kQ current limiting resistor provide power on/ off indication. The remainder of the circuit is powered via a lO0Q decoupling resistor and voltage clamping diode ZDl. This zener diode is used to quench any high voltage spikes which could otherwise damage the 7555. Finally, the decoupled supply rail to the ICs is filtered using 100µF and lOµF electrolytic capacitors. Board assembly The PC board is secured to the bottom of the case using machine screws & nuts. Be sure to use mains-rated cable for the two connections to the output socket. All the parts except those for the optional hand-held controller are mounted on a PC board coded SC11106921 and measuring 123 x 82mm. Fig.3 shows the parts layout on the PC board. Begin construction by soldering in the eight wire links. These links should all be nice and straight, so that they don't short out other components on the board. If necessary, you can JUNE 1992 85 the two ICs, the two MTP3055 MOSFETs (Ql & Q2), zener diode ZD1 and transistor Q3. Make sure that all these parts are correctly oriented. In particular, mount the two MOSFETs with their metal tabs facing away from transformer T2. It is not necessary to fit heatsinks to the MOSFETs in this circuit because of the low power involved. PCB and SCHEMATIC CAD - :- - --- --- - ·-- - -· -- - - - ·':!: · ... i -T~ IF AMPLIFIER ' ,· t !~ Initial testing - I' !i' i, ;J : i ____ _______ ______ _'- -- r·----------~ C•U!Sif.ff.• -~ ~ t'l: 5~1. =~l: -., : H ' 1111 I . ... , Fig.4: here are the wiring details for the optional hand-held controller. Note the link between two of the pot terminals. lll+lllllllllllllfHHllllflll"l'III t . "'°MI o Qg o f'III • IJ EASY-PC • Runs on PC/XT/AT/286/386 with Hercules, CGA, EGA or VGA. • Design Single sided, Double sided and Multilayer boards • Provides Surface Mount support • Standard output includes Dot Matrix/Laser/Inkjet printers, Pen Plotters, Photo-plotters and NC Drill • Award winning EASY-PC is in use in over 12,000 installations in 70 Countries World-Wide • Superbly Easy to use • Not Copy Protected straighten the link wire by clamping one end in a vyce and pulling on the other end with a pair of pliers so that the wire stretches slightly. Once the links are in, solder in the resistors, capacitors and the two M205 fuseclips. Note that each fuseclip has an outer guard to keep the fuse in place, so be sure to install the fuseclips the right way around. The 150kQ resistor shown dotted should be omitted if you intend using the external hand-held controller but otherwise should be included (see below). The semiconductors can now all be installed - see Fig.1 for the pin connection details. These parts include At this stage, the board assembly will be complete apart from-fitting the two power transformers. Before installing these, it's a good idea to check that the circuit is working up to this point. .If you haven't already done so, you will have to fit a 150kQ resistor between pins 3 & 6 of ICl before testing can proceed. This resistor can be temporarily tacked into position if you intend using the hand-lfeld controller. To test the unit, first connect the LED via a couple of flying leads, then connect a 12V power supply (be careful with the polarity). This need only be a 12VDC 300mA plugpack to start with since we aren't driving a load. If you have a CRO handy, switch the circuit on and check the waveforms on pins 13 & 14 of IC2. You should see a switching waveform at about 50Hz on both pins (see Fig.2). If you don't, disconnect the supply and check the PC board for shorts, missed solder joints and parts in the wrong way around. If you don't have a CRO, check the voltages on pins 13 & 14. If the circuit is working correctly, the meter will indicate an average voltage of 6V DC at these two points. Options: • 1000 piece Schematic symbol library • Surface Mount symbol library • Gerber Import facility For full info 'phone, fax or write: BTC PO BOX -432 GARBUTT 4814 QLD. PH (077) 21 5299 FAX (077) 21 5930 86 SILICON CHIP A small plastic zippy case holds all the parts for the hand-held controller. Tie a knot in the connecting cable so that it cannot be pulled out of the case. PARTS LIST 1 PC board, code SC11106921, 123 x 82mm 1 plastic zippy box, 150 x 90 x 50mm 1 SPST toggle switch 2 M205 fuseclips 1 M205 5A fuse 1 flush panel-mount mains socket 2 ?VA mains transformers with dual 9V secondaries (Altronics M-7118 or Jaycar MF-1006) 4 rubber feet SC11106921 Fig.5: check your etched PC board against this full-size artwork & correct any defects before installing the parts. Assuming everything is working correctly, you can now install the two transformers. Don't forget to remove the 150kO resistor you tacked into circuit if you will be using the external hand-held controller. Final assembly The PC board is mounted towards one end of the specified case so that there is plenty of clearance between the transformers and the mains socket. Use the board as a template for marking out its mounting holes, then drill the holes and install machine screws and nuts (to act as spacers) at each location. Next, you'll need to mark out and "cut" the hole for the front of the mains socket. Once the hole has been marked, it can be made by first drilling a series of small holes around the inside circumference, then knocking out the centre piece and filing to a smooth finish. The square cutout for the power switch (S1) at the other end of the case can be made in similar fashion. You will also have to drill holes next to this switch for the DIN socket (if necessary) and power SUP.ply leads, plus a hole next to the mains socket for the power indicator LED. The assembly can now be completed by connecting flying leads to the external wiring points on the board, then mounting the various items inside the case and installing the remammg wumg. Note that 240VAC cable should be used for the connections between the PC board and the mains socket. Remote control The parts for the hand-held controller fit comfortably into a small zippy box measuring 83 x 54 x 28mm. Fig.4 shows the wiring details. The pot (VRl) and the two switches are simply mounted directly on the lid of the case and the two resistors then soldered to the appropriate terminals as shown in Fig.4. The four leads (we used 5-way telephone cable) from the handheld controller emerge through a hole in one end of the case and terminate in a 5pin DIN plug. Make sure that the plug wiring matches the wiring to the DIN socket in the inverter unit. Final testing To test the unit, connect it to a 12V car battery and plug a 15W lamp into the mains socket. The lamp should light as soon as the inverter is switched on and should deliver about the same output as it does when plugged into a standard mains outlet. If the inverter does not function, switch it off immediately and check for wiring errors and for bad or missed solder joints. If these checks don't reveal anything, re-apply power and check that the supply rails to the ICs are correct. You should find +12V on Semiconductors 1 7555 CMOS timer IC (IC1) 1 LM339 quad comparator (IC2) 2 MTP3055 N-channel MOSFETs (01 ,02) 1 BC548 NPN transistor (03) 1 5mm red LED (LED1) 1 15V 1W zener diode (ZD1) Capacitors 1 100µF 16VW RB electrolytic 1 10µF 16VW RB electrolytic 2 0.1 µF 63VW MKT polyester Resistors (0.25W, 1%) 1 150kO 1 8.2kO 6 47kO 1 1.6kO 1 15kO 2 1kO 2 10kO 5 1000 Miscellaneous Insulated hookup wire, machine screws, nuts & washers . Hand-held controller · 1 zippy box, 83 x 54 x 28mm 1 SPST switch (S2) 1 SPST normally open momentary switch (S3) 1 50kn linear potentiometer (VR1) 1 100kn 1% 0.25W resistor 1 5-pin DIN plug 1 5-pin DIN socket 2 metres of 4-core cable 1 knob to suit pins 4 & 8 of ICl and on pin 3 of ICZ. Finally, if you have access to an oscilloscope, you can check the circuit waveforms against those shown in Fig.2. Note, however, that the waveform at the outputs of IC2c & IC2d will be a combination of the separate waveforms shown in Fig.2. SC JUNE 1992 87 Silicon Chip BACK ISSUES July 1988: Stereo Control Preamplifier, Pt.2; Fitting A Fuel Cut-Off Solenoid To Your Car; 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? August 1988: Building A Plasma Display; Universal Power Supply Board; Remote Chime/ Doorbell ; High Performance AC Millivoltmeter, Pt.1; Discolight Light Show, Pt.2; Getting The Most Out Of Nicad Batteries; Data On Insulated Tab Triacs. September 1988: Hands-Free Speakerphone; Electronic Fish Bite Detector; High Performance AC Millivoltmeter, Pt.2; Build The Vader Voice; Motorola MC34018 Speakerphone IC Data; 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. November 1988: 120W PA Amplifier Module (Uses Mosfets); Poor Man's Plasma Display; ACJtomotive Night Safety Light; Adding A Head- set To The Speakerphone; How To Quieten The Fan In Your Computer; Screws & Screwdrivers, What You Need To Know; Diesel Electric Locomotives. December 1988: 120W PA Amplifier (With Balanced Inputs), Pt.1 ; Diesel Sound Generator; Car Antenna/Demister Adaptor; SSB Adaptor For Shortwave Receivers; Why Diesel Electrics Killed Off Steam ; Index to Volume 1. January 1989: Line Filter For Computers; Ultrasonic Proximity Detector For Cars; 120W PA Amplifier (With Balanced Inputs) Pt.1; How To Service Car Cassette Players; Massive Diesel Electrics In The USA; Marantz LOSO Loudspeakers. February 1989: Transistor Beta Tester; Minstrel 2-30 Loudspeaker System; LED Flasher For Model Railways (uses LM3909) ; Build A Simple VHF FM Monitor (uses MC3362), Pt.1; Lightning & Electronic Appliances; Using Comparators to Detect & Measure. March 1989: LED Message Board, Pt.1; 32Band Graphic Equaliser, Pt.1 ; Stereo Compressor For CD Players; Amateur VHF FM Monitor, Pt.2; Signetics NE572 Compandor IC Data; Map reader For Trip Calculations; Electronics For Everyone -Resistors. April 1989: Auxiliary Brake Light Flasher; Electronics For Everyone: What You Need to Know About Capacitors; Telephone Bell Monitor/ Transmitter; 32-Band Graphic Equaliser, Pt.2; LED Message Board , Pt.2. May 1989: Electronic Pools/Lotto Selector; Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference; LED Message Board, Pt.3; Electronics For Everyone - All About Electrolytic Capacitors. June 1989: Touch-Lamp Dimmer (uses Siemens SLB0586) ; Passive Loop Antenna For AM Radios; Build A Universal Temperature Controller; Understanding CRO Probes; LED Message Board, Pt.3. July 1989: Exhaust Gas Monitor (Uses TGS812 Gas Sensor) ; Extension For The Touch-Lamp Dimmer; Experimental Mains Hum Sn iffers; 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 3-Phase Electric Locomotives. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC 13024 and TX7376P) Pt.1; Alarm-Triggered 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). October 1989: Introducing Remote Control; FM Rad io Intercom For Motorbikes (Uses BA1404 & TDA?000) Pt.1; GaAsFet Preampli- Use this handy form to order your back issues Please send me a back issue for: October 1988 0 November 1988 March 1989 O April 1989 August 1989 0 September 1989 January 1990 0 February 1990 June 1990 0 July 1990 o November 1990 0 December 1990 O April 1991 0 May 1991 0 September 1991 0 October 1991 O February 1992 O March 1992 O O O 0 O 0 O 0 0 O O O O O 0 July 1988 December 1988 May 1989 October 1989 March 1990 August 1990 January 1991 June 1991 November 1991 April 1992 0 August 1988 O January 1989 O June 1989 o November 1989 0 April 1990 0 September 1990 o February 1991 0 July 1991 O December 1991 0 May 1992 Enclosed is my cheque/money order for $___or please debit my: D Bankcard Card No. ~~I l~'---'---'~I I I I~~~ Signature _ _ __ _ _ _ _ __ _ _ Card expiry date_ _ /_ _ Name ___ ___ ____ _ _ _____ _ _ ___ ____ Street _ _ _ _ _ _ _ __ _ _ _ __ _ _ __ _ _ __ _ _ L l ---, O O 0 0 O 0 0 September 1988 February 1989 July 1989 December 1989 May 1990 October 1990 March 1991 o August 1991 0 January 1992 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 l Or call (02) 979 5644 & quote your credit card details. Fax (02) 979 Suburb/town _ _ _ _ _ __ _ _ __ ___ Postcode _ _ _ _ __ 6503 ______ _ __________ ___ _ _____ __ _ _ _ _ _ ______ 88 SILICON CHIP I _ _ _ fier For Amateur TV; 1Mb Printer Buffer; 2Chip Portable AM Stereo Radio, Pt.2; Installing A Hard Disc In The PC. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); 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. Cost 3-Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band. 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: How To Connect Two TV Sets To One VCR; A Really Snazzy Egg Timer; Low-Cost Model Train Controller; Battery Powered Laser Pointer; 1.5V To 9V DC Converter; Introduction To Digital Electronics; Simple 6Metre Amateur Transmitter. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Speeding Up Your PC; Phone Patch For Radio Amateurs; Active Antenna Kit; Speed Controller For Ceiling Fans; Designing UHF Transmitter Stages. December 1990: DC-DC Converter For Car Amplifiers; The Big Escape - A Game Of Skill; Wiper Pulser For Rear Windows; Versatile 4Digit Combination Lock; 5W Power Amplifier For The 6-Metre Amateur Transmitter; The Great Green CD Pen Controversy; Index To Volume 3. February 1990: 16-Channel Mixing Desk; High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2; PC Program Calculates Great Circle Bearings. 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. March 1990: 6/12V Charger For Sealed LeadAcid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2 ; Using The UC3906 SLA Battery Charger IC . February 1991: Synthesised Stereo AM Tuner, Pt.1 ; Three Inverters For Fluorescent Lights; Low-Cost Sinewave Oscillator; Fast Charger For Nicad Batteries, Pt.2; How To Design Amplifier Output Stages; Tasmania's Hydroelectric Power System. April 1990: Dual Tracking ±50V Power Supply; VOX With Delayed Audio; Relative Field Strength Meter; 16-Channel Mixing Desk, Pt.3; Active CW Filter For Weak Signal Reception; How To Find Vintage Radio Receivers From The 1920s. May 1990: Build A 4-Digit Capacitance Meter; High Energy Ignition For Cars With Reluctor Distributors; The Mazzie CW Transceiver; Waveform Generation Using A PC, Pt.3; 16Channel 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. 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 The Config.Sys & Ansi.Sys Files. · April 1991: Steam Sound Simulator For Model Railroads ; Remote Controller For Garage Doors, Pt.2 ; Simple 12/24V Light Chaser; Synthesised AM Stereo Tuner, Pt.3; A Practical Approach To Amplifier Design, Pt.2; Playing With The Ansi.Sys File; FSK Indicator For HF Transmissions. May 1991: Build A DTMF Decoder; 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1; Setting Screen Colours On Your PC. July 1990: Digital Sine/Square Generator, Pt.1 (Covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; LowCost Dual Power Supply; Inside A Coal Burning Power Station; What To Do When Your Computer Goes Bung, Pt.3; Weather Fax Frequencies. June 1991: A Corner Reflector Antenna For UHF TV; 4-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. 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; What To Do When Your Computer Goes Bung, Pt.4. July 1991: Battery Discharge Pacer For Electric Vehicles; CD Error Analyser, Pt.1; Loudspeaker Protector For Stereo Amplifiers; 4Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2; PEP Monitor For Transceivers September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs; Power Supply For Burglar Alarms; Low- 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; Installing Windows On Your PC; Step-By-Step 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; The Basics Of ND & DIA Conversion; Windows 3 Swapfiles, Program Groups & Icons; How Glass-Mount Antennas Work. October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator Mk.11; Magnetic Field Strength Meter; Digital Altimeter For Gliders & Ultralights, Pt.2; Getting To Know The Windows PIF Editor. November 1991: Colour TV Pattern Generator, Pt.1; Battery Charger For Solar Panels; Flashing Alarm Light For Cars; Digital Altimeter For Gliders & Ultralights, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2; Error Analyser For CD Players Pt.3; Modifying The Windows INI Files. December 1991: TV Transmitter For VCRs With UHF Modulators; Build An lnfrared Light Beam Relay; Compact Solid-State Laser Pointer; Build A Colour TV Pattern Generator, Pt.2; The Miracle Piano Teaching System; Windows 3 & The Dreaded Unrecoverable Application Error. January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V 8A Power Supply, Pt.1; Baby Room Monitor/FM Transmitter; Automatic Controller For Car Headlights; Experiments For Your Games Card; The GPS Satellite Navigation System. February 1992: Compact Digital Voice Recorder; 50-Watt/Channel Stereo Power Amplifier; 12VDC/240VAC 40-Watt Inverter; Adjustable 0-45V 8A Power Supply, Pt.2; The Mobile Telephone Revolution; Designing A Model Speed Controller. March 1992: TV Transmitter For VHF VCRs; Studio Twin Fifty Stereo Amplifier, Pt.1; Thermostatic Switch For Car Radiator Fans; Telephone Call Timer; Updating The Resistor/ Capacitor Scene; Coping With Damaged Computer Directories. April 1992: lnfrared Remote Control For Model Railroads; Differential Input Buffer For CROs; Studio Twin Fifty Stereo Amplifier, Pt.2; Understanding Computer Memory; Switching Frequencies in Model Speed Controllers; Aligning Vintage Radio Receivers, Pt.1 . May 1992: Build A Telephone Intercom; LowCost Electronic Doorbell ; Battery Eliminator For Personal Players; lnfrared Remote Control For Model , Railroads, Pt.2; A Look At Large Screen High Resolution Monitors; OS2 Is Really Here. 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 sold-out issues, 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. JUNE 1992 89 ASK SILICON CHIP Got a technical problem? Can't underst~nd 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. Questions on subwoofer design Some years ago I convinced my wife about the need to incorporate a subwoofer into our lounge room (I am partial to organ music). At the time, I was under the apparently misguided notion that it would be necessary to use a large driver. I selected the 15inch white polypropylene drive from the then current Jaycar · catalog and applied the Thiele/Small formulas extracted from various articles on the design of vented loudspeaker enclosures. Having determined the necessary dimensions I set about constructing a rather large book case with the sub-woofer built into the lower section (the box volume was approximately 330 litres). Unfortunately, something went wrong between the theory and the practice since the results have been rather disappointing. After much patient effort, I have again obtained permission to alter the lounge room configuration. I am about to incorporate a Yamaha DSP-E1000 signal processor into the system and this time the subwoofer has to be right! My main speakers use the Vifa SA- Soft start for incandescent lamps I remember seeing a circuit that I think was called a light saver - it gradually increased the voltage to an incandescent light after switch on to prevent surges and burnout. Do you know of it, or of anything similar? Also, I have a clipping from the American magazine "Omni". The advertisement refers to a diode that prolongs light globe life; do you know what this might be? (A. K., Sheidow Park, SA). • We have not described a light saver circuit project, although one 90 SILICON CHIP 130 kit. I am trying to achieve well defined bass to as close to Z0Hz as possible; ie, flat to 32Hz with the -3dB point approaching Z0Hz. I will use the lower bands of a Studio Series 1/3 Octave Equaliser to match the output level of the main speakers to the subwoofer. During this time, I have been waiting for the SILICON CHIP subwoofer project which is apparently somewhere in the pipeline. Since this has not yet materialised, can you advise me whether either of the subwoofer drivers advertised by Jaycar (HF801, HF1001) is suitable? Would it be better to use the 8-inch or the 10-inch driver? Would it be better to use one driver or two drivers? What would be a suitable box volume? (I should be able to manage 150 to 200 litres). What would be the correct port dimensions? If these drivers are not suitable, do you have any other suggestions? If you have access to the LEAP design software, any theoretical frequency response plots would be appreciated. (A. H., Bradbury, NSW). • In the past, we have designed a number ofloudspeakers using Thiele/ Small parameters and the results have was described in another magazine about six years ago. As far as we can determine, it is no longer available in kit form. The magazine clipping on the "Diolight" apparently refers to a standard lamp with a power diode fitted in the base. This would certainly increase the life of the lamp but would reduce its brilliance unless the filament had been designed for the reduced voltage. However, there would be a substantial problem with flicker. This may not be so bad with the 60Hz supply in America but would be objectionable with the 50Hz supply in Australia. been disappointing. Based on this experience, we cannot make any recommendations on the suitability of any woofer or give suggested dimensions for a suitable subwoofer enclosure. Unless we actually produce a prototype which has reasonable performance, we cannot give out this sort of information. As far as our own subwoofer project is concerned, it is on the backburner for at least the time being. Masthead amplifier & corner reflector antenna The TV aggregation changes became effective in my area, 1\veed Heads, Brunswick Valley, last January. ABC channel 6 and channel 8 NRTV remain on VHF and the additional channel is UHF 47, with channel 44 to follow in June. Where I live, Ocean Shores, reception of UHF is poor so I built the corner reflector antenna described in the June 1991 of SILICON CHIP and the masthead amplifier described in the August 1991 issue. I made a slight modification to the antenna, bending the bow tie along its length to parallel the reflector to give a small improvement. The antenna performs well over both VHF and UHF. Channel 6 ABC VHF produces a perfect picture; channel 8 NRTV VHF gives a satisfactory picture, with an occasional misspelling on Teletext; and UHF channel 47 gives good colour and definition with clear sound and overall mild snow (but is quite watchable). To obtain these results, a masthead amplifier is necess~. The masthead amplifier described in August gave no result when connected. Channel 6 showed a blurry out of colour image which was almost impossible to identify ·as a picture; channel 8 had no picture with black and white snow; and on channel 47 there was only heavy snow. There was no sound on any of the channels. A test of the amplifier showed cor- rect voltages at all points, both AC and DC. The OM350, being the only active component between antenna and receiver, was therefore suspect and a new one was installed with similar disappointing results. I borrowed a friend's amplifier to obtain the good result described above. The borrowed amplifier has a gain of 26dB. The SILICON CHIP amplifier has a stated gain of 18dB and surely should perform better. What else can I do? If nothing, then I have an expensive piece of junk. Can masthead and distribution amplifiers be connected in series? Also why are diplexers required to connect VHF, UHF and/or FM antennas to a common down cable? (R. W., Brunswick Heads, NSW). • In view of the fact that you have checked the hybrid chip, the other components which should be checked are the diodes and the capacitors. One or more of the capacitors may be open circuit and one of the diodes could be short circuit. Also, check to make sure that you have no dry joints. Masthead and distribution amplifiers can be connected in series, provided that the signal level out of the first unit does not overload the following unit. As an example of cascaded amplifiers, have a look at the TV Transmitter for UHF VCRs, published in the December 1991 issue of SILICON CHIP. Diplexers are required for connecting VHF and UHF antennas to a common cable so that the antennas are isolated from each other and, therefore, do not degrade each other's characteristics. Source of semiconductors I cannot obtain QB, QlO (TIP142), Q9 or Qll (TIP147) for the new Studio Twin 50 Stereo Amplifier. Jaycar advertised a kit in their new catalog but will not sell the Darlingtons separately. Can you please advise of a stockist? I also have a number of questions involving the Differential Input Buffer for Oscilloscopes published in the April 1992 issue of SILICON CHIP: (1) Who stocks Siemens 11300 DPTOs? (2) Are normal CRO probes (1:1) rated at full 240VAC RMS mains? (3) Wouldn't a plastic case be more suitable for an "isolated" hobby project? Queries on the multisector burglar alarm I am at present building a kit of the multi-sector burglar alarm from the June 1990 issue. I have two problems which you may be able to solve. (1) The siren has an on-time of 10 minutes. I find this too long and would like to have the siren run for a maximum of 5 minutes. What modifications would this require? It appears that the RC components on pins 9, 10 & 11 of IC4 may have to be altered. (2) There is no mention of the type of horn speaker to use with the system. I assume that an 8ohm type should be used. Can two horn speakers be connected in par- (4) If the BNC differential sockets or probes have insulation failure, won't a metal case become live if the measured equipment fuse does not blow? Finally, I have a question on car radio input impedance. We use car radios (FM) to pick up Darwin in stereo 260km away using antennas mounted on top of 15-metre high buildings. We need to know the best antenna and cable but don't know the car radio antenna's input impedance. (D. G., Jabiru, NT). • You can purchase TIP142/147s from Geoff Wood Electronics. Phone them on (02) 428 4111 or fax (02) 428 5198. Most oscilloscope probes are rated at 600VDC and 600VAC peak. This is adequate for working on 240VAC circuits. Check the rating on your probes before using them with this device. Siemens 11300 ICs are available from Reserve Electronics. Phone them on (02) 906 8486. A metal case was specified for the Differential Input Buffer so it is earthed to the oscilloscope's mains earth. This earths the BNC sockets which may otherwise become live if the circuit was built into a plastic case. If the probes do happen to break down, it will be much safer if the case is earthed. The FM antenna input impedance of a car radio can be assumed to be quite low, to give a reasonable match to a whip antenna. However, we would allel to the output of transistor Q3? (F. P., Bedford, WA). • You can alter the period for the 10-minute timer comprising IC4, IC6 & IC7 by changing the preset number which is loaded into IC7. The. circuit is set so that binary 15 (1111) is loaded into IC7 each time the circuit is armed. You can change it to load in binary 7 (0111) by cutting the track to pin 3 and then connecting pin 3 to the 0V line. This will give an alarm sounding time of 7 x 40 seconds, or 4 minutes and 40 seconds. The horn speaker should be a standard 8-ohm unit without any internal amplifier. Two horn speaker~ could be connected but you will then need to mount the BD681 transistor (Q3) on a heatsink. recommend the use of a conventional high gain Yagi antenna cut especially for the FM band. It should be connected to the car radio antenna via 75ohm coax cable. A design for a 5-element Yagi antenna for the FM band was published in the October 1988 issue of SILICON CHIP. Back issues are available for $5.00 including postage. Computer control via the printer port I very much enjoyed reading the article "Experiments For Your Games Card" in the January 1992 issue of SILICON CHIP, the subsequent production of a PC breakout board by RCS Radio and the Circuit Notebook article "Using Your Games Port for Data Input" in the March issue. It is fascinating to see how a computer can be made to interact with the real world in both an inexpensive and uncomplicated way. I know that it is possible to use digital I/O boards to control external devices but commercial I/O boards are expensive. What I want to know is whether it is possible to use a parallel printer port to control an external device; eg, to switch a relay on and off. (A. L., Haberfield, NSW.) • We published a Multi-Purpose I/O Board for PCs in the March 1991 issue. This operates from the parallel JUNE 1992 91 Fluorescent light inverter problems I am having difficulty with the 12 volt fluorescent light inverter described in the February 1991 issue. I have built both the 20W and 40W versions; neither will work! Naturally, I have carefully checked component orientation, the transformer air gap, and that the heatsink is correctly isolated from transistors. When connected, the 20W version draws about 3 amps, jumping to 5 amps after a couple of seconds. The 40W version draws a steady 5 amps. In neither case does the tube port and the associated article should answer most of your questions. Can you solder nicad cells? I would like to comment on the latest issue (April 1992) and in particular the article on the Infrared Controller. I can't recall any mention of the need to point the unit at the receiver or not for operation, as is the case with a cordless remote for a television set. Would you be able to clarify this point for me and for other readers please? My second query is what danger is there in soldering connections on nickel cadmium rechargeable batteries? The reason for this query is that recently I fitted new batteries to a cordless can opener and repaired a break in the batteries in my cordless drill, both of which required soldering. But when I told my friend from Telecom what I had done, he told me that I was lucky they had not exploded. The batteries that I used were supplied by the local Tandy agent and are provided with tabs to solder together. In the case of my cordless drill, there are five "C" size cells with tabs and the five batteries would seem to have been spot welded together. The joint between two of the batteries had broken when the drill was dropped from a height of about one metre onto a carpeted floor. This was soldered together and the drill is as good as new. 92 SILICON CHIP light or even flicker. Several tubes, known to be good, have been tried. I suspect the transformer to be the problem but I have wound them exactly as specified. Can you suggest any tests that might locate the problem? I don't have access to a CRO. (G. M., Tecoma, Vic). • The most likely reason for the heavy current drain is incorrect connection of the primary windings - probably both transistors are turned on, leading to the heavy current drain. If the circuit is oscillating, you should hear it whistle and you should be able to measure a high output voltage across the secondary winding. My next question is about the use of transformers which are more than about 10 years old. This same friend from Telecom told me that the material that was used for insulation between the laminations gives off a gas called PCB which is harmful if inhaled. I have several power packs which were made by Cyclops for Triang Railways. Some work, some don't but the transformers are still OK and I have built new controllers to use with these now suspect transformers. Could you please tell me if this is true or false and if it is dangerous to use them? My next query concerns these same power packs and the germanium transistor that was used as a power booster. It has the identification OC903 and is of the same style as a 2N3055 (ie, a TO-3). I cannot find this or any information about it in any books of equivalent types. I don't even know if it is NPNorPNP. I tried to replace this with a 2N3055 but this caused the cut-out to open and close in terror. Perhaps you or a reader could tell me the correct substitute. The power pack by the way is aP5T. My last query is about remagnetising model train motors. I would like to build a remagnetiser. I have seen this carried out in several ways, all of which would seem to me to be a bit dangerous and rather haphazard. One method I have seen is to use two transformers, one static and the other suspended by a piece of brass rod which was raised and lowered by hand. Another one was made from an old TV transformer and a couple of chokes and a switch - all very dangerous in my opinion. I would like to know how to sort out the polarity of such a device and how to go about remagnetising the magnet in a Ringfield motor. (R. R., Cape Paterson, Vic). • We shall answer each of your questions in turn. In a small room, there is little need to point the remote control at the receiver as the infrared signal bounces off the walls and ceilings. In a large room though, it becomes necessary to point the controller at the receiver, just as you would with a TV or VCR. You can solder the tabs of nickel cadmium batteries and there is very little danger of explosion, although they ea~ certainly explode if they are thrown into a fire. Ordinary transformers as used in domestic electrical equipment are usually not impregnated at all while the older types made twenty years ago or more were generally dipped in varnish after being subjected to heat and vacuum to dry them out. Provided old transformers do not show any signs of corrosion, which generally indicates they have been subjected to a lot of moisture, they should be quite safe to use. The only transformers which had PCBs (poly chlorinated biphenyls) in them are large oil-cooled types as used by the electricity authorities (and Telecom). PCBs have been banned since about 1976. We published a feature article on PCBs in the October 1990 issue. Most germanium power transistors will be PNP types since they were much easier to make than NPN types. Thus, if you were going to substitute a silicon power transistor, you should use a PNP type such as an MJ2955. Unfortunately, we do not have any information on remagnetising small perman.ent magnet motors. Perhaps one of our readers can provide information on this topic. Notes & Errata Thermostatic Switch For Car Radiator Fans, March 1992: the wiring diagram on page 43 shows the collector ofQ3 going to FAN +ve. It should go to the FAN -ve. SC . 1 I .., , ,,,,"' .~ 1 1 - --.i,,_,'-,./ "WI ... I 1 ... I, 1- ORDER FORM 1 I .,J flf::}!,7 f ..J/J• ,,,i l' 7 .. ..... ,i I'•< BACK ISSUES* MONTH MONTH YEAR YEAR MONTH YEAR MONTH YEAR *Back issues are $A5 each (incl. postage). Overseas orders add $A 1 per issue for postage. BINDERS Please send me _ _ SILICON CHIP binder(s) at $A14.95 each (incl. postage). Overseas orders please add $A3.00 each for postage. TOTAL PRICE $A SUBSCRIPTIONS i. 0 New subscription - month to start 0 Renewal - Sub. No. r------------, 0 RATES (please tick one) 2 years (24 issues) 0 0 0 0 0 Australia Australia with binder(s)* NZ & PNG (airmail) Overseas surface mail Overseas airmail 1 year (12 issues) 0 0 0 0 0 $A84 $A105 $A130 $A130 $A240 I I I I I I I I I I Gift subscription ~ $A42 $A53 $A65 $A62 $A120 *1 binder with 1-year subscription; 2 binders with 2-year subscription I I YOUR DETAILS .·• Your Name (PLEASE PRINT) Address Daytime telephone number Postcode or please debit my Enclosed is my cheque/money order $ 0 Bankcard Card No. 0 Visa Card 0 1 GIFT SUBSCRIPTION DETAILS Month to start Message Gift for: Name I I I I I I I I I I ~ (PLEASE PRINT) I Street I I I I Suburb/town I I I Postcode I State I IL _ _ _ _ _ _ _ _ _ _ _ _ .JI Signature Master Card I I I I II I I I II I I I II I I I I Phone (02) 979 5644 Fax (02) 979 6503 9am-5pm Mon-Fri. Please have your credit card details ready Fax the coupon with your credit card details 24 hours 7 days a week Card expiry date I Mail coupon to: . Freepost 25 Silicon Chip Publications PO Box 139, Collaroy Beach 2097 No postage stamp required in Australia ]UNE 1992 93 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. r------- ------------------, : CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $10.00 for up to 15 words plus 40 : I I I I I I cents for each additional word. Display ads (casual rate): $20 per column I centimetre (Max. 10cm). Closing date: five weeks prior to month of sale. I To run your classified ad, print it clearly on the form below or on a separate sheet I of paper & send it with your cheque or credit card details to : Silicon Chip I Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02) I ~ ~I 1 _ _ _ _ __ _ _ _ __ _ _ __ I I 1 I ANTIQUE RADIO ANTIQUE RADIO restorations. Your one-stop rad io repair shop. Specialising in restoring vintage radios including chassis rewiring, re-condensing, quality new parts, valves, valve sockets, speakers, power & audio transformers. Secondhand radio dials & parts for most brands & models. About 400 radios in stock for sale, restoration & parts. Every restored wireless is covered by a 2year warranty on parts & labour. We restore damaged woodwork & cabinets & French polish (approx. 40 coats). Vintage car radios available for sale or restoration . Repairs done on tape decks & amplifiers. Open Sat. 10am-5pm; Sun. 12.30-5pm . 109 Cann St, Bass Hill, NSW 2197. Phone (02) 645 3173 BH or (02) 726 1613 AH. FOR SALE MY AUSTRALIAN DESIGNED low cost super fast Z80 micro-controller development system has gained acceptance already with educational institutions. Pop it on the end of any PC MS-DOS or Z80 machine&awayyougo. Boards, EPROM & 720Kb disc $76 including postage for a short form kit. Gee, I wish I had this when I was a kid. For more information, send a 45c stamp to Don McKenzie, 29 Ellesmere Crescent, Tullamarine 3043. Phone (03) 338 6286. Enclosed is my cheque/money order for $._ _ __ o Bankcard Card No. D Visa Card or please debit my D Master Card '---'---'----'----'I I'--~~I I'--J..__J___~II'--'----'---~ Signature_ __ _ _ __ __ _ _ Card expiry date_ _ _,/_ __ Name _ _ __ _ __ _ _ _ _ __ _ _ _ _ __ __ __ Street - ----'- - - - - -- - -- - -- - -- - - - Suburb/town _ _ _ _ _ _ _ _ _ _ _ Postcode._ __ _ __ XI I I I I I I I I I L------ -------- ----------- ~ 94 SILICON CHIP WEATHER FAX programs for IBM XT/ ATs *** "RADFAX2" $35 is a high resolution, shortwave weather fax, Morse & RTTY receiving program. Needs CGA, SSB HF radio & Radfax decoder. Also "RF2HERC", "RF2EGA" & "RF2VGA", same a,s RADFAX2 but suitable for Hercules, EGA & VGA cards respectively. $35. *** "SATFAX" $45 is a NOAA, Meteor & GMS weather satellite picture receiving program. Uses EGA & VGA modes, needs EGA or VGA colour monitor & card, plus "WEATHER FAX" PC card . $45. *** All programs are on 5.25inch or 3.5-inch discs (state which) & include documentation. Add $3 postage. Only from M. Delahunty, 42 Villiers MEMORY EXPANSION r UNIDEN SCANNERS DON'T PAY MORE! PRICES AT MAY 3RD, 1992 SIMM 1Mbx9 sons $48 1Mbx8100ns $43 1Mbx8 sons $48 4Mbx980ns $183 4Mbx8 sons $175 256x9 sons $16 (FOR SIP ADD $1) TOSHIBA T1000SE 2Mb T2000SX 4Mb T1600 2Mb T31 OOOSX 2Mb T3200SX 2Mb T3200 3Mb T52002Mb T2000SX8Mb $230 $320 $140 $135 $135 $230 $150 $760 DRAM-DIP 41100080 256x480 41256 80 1Mbx480Z 1Mbx480S 1OOXLT RRP $449.95. Our price $409 100 memories, Lo-Hi VHF, Air, UHF 200XLT RRP $549.95. Our Price $477 200 memories, Lo-Hi VHF, Air, UHF, 800 MHz $80 $420 $325 $475 $530 CO-PROCESSORS 387/33/40 $235/$280 387/20/25 $210/$215 SX20/25 $155/$170 287/10/20 $100/$125 Sales Tax 20%. Overnight Delivery. Credit Cards Welcome. PELHAM 50XL RRP $299.95. Our price $211 10 memories, Lo-Hi VHF, UHF $5.40 $5.60 $2.00 $25.00 $25.00 DRIVES 3½ PANAS 1.44 S'GATE IDE 64/16 S'GATE IDE 42/28 S'GATE IDE 108/16 S'GATE IDE 130/16 Tel (02) 9B0 69B8 Fax (02) 980 699 DIGI-CART DSP BOARD For 16-bit IBM compatibles. Broadcast quality 44.1 kHz/16 bit stereo audio with audio recorder software. $1599 + Tax Custom software service for applications available. PC Computers (08) 332 6513 36 Regent St Kensington SA All prices include delivery. Phone any1ime today! (03) 883 9535; Fax (03) 432 0716 TopCom Communications PO Box 336, Greensborough, Vic 3088. ~ ~ TRANSFORMER REWINDS ALL TYPES OF TRANSFORMER REWINDS FIX-A-KIT KIT REPAIR & CONSTRUCTION 3 MONTHS WARRANTY ON REPAIRS 12 MONTHS WARRANTY ON CONSTRUCTION TECHNICAL ASSISTANCE HVCAL ELECTRONICS TRANSFORMER REWINDS Design, Manufacture & Repair of Electronic Reply Paid No.2, PO Box 438, Singleton, NSW 2330. Ph: (065) 761291. Fax: (065) 761003. (02) 633 5477 PLAY MODULE: 16 x 2 with provision for backlighting -$22. * LASER DIODE POINTER: pen sized 5mW pointer in presentation case - $199. * LASER DIODE GUNSIGHT: small adjustable 5mW unit with one pistol or rifle mount$299. * VISIBLE LASER DIODE HEAD: 3V battery operation, 5mW670nm $135. * ARGON LASER HEADS: used but "low hours" units, deliver 30-1 S0mW of bright blue beam! - $800. * BINOCULAR IR VIEWER: clip over a standard helmet - $649. * 12V OPERATED LASER: one used 3mW Siemens laser head plus an inverter kit - $109. * 12V OPERATED LASER: one new 1mW tube plus an inverterkit-$149. * MAINS OPERATED LASER: new 10mW tube plus a new potted mains power supply$389. * 12V LASER BARGAIN: 12V laser inverter kit plus one of our "mystery" tubes, you wont be disappointed $89. * MAINS OPERATED LASER BARGAIN: potted mains power supply plus one of our "mystery" tubes - $139. * 40kHz ULTRASONIC TRANSDUCERS: $4 for a pair, 40kHz xtal - $3.50 * PIR DETECTORS: dual element units supplied with a lens and a suitable circuit- $9.90 * SECOND GENERATION NIGHT VISION TUBES: very small fibre optically coupled tubes that will perform under starlight illumination, rejects with some blemished - from $500 * ELECTRO$: 2200µF/35Vradial $1.20; 470µF/35V radial 60c; 6800µF/ 35V snap in $3. * STEPPER MOTORS: 5V, 7.5-deg., 6.6-ohm, 2-phase - $12. * MAGNIFIER LAMP: 750mm spring balanced arm reach and metal clamp, for 120V operation but easy to rewire, porcelain lamp socket - $79. * MYLAR CAPACITORS: 0.047µF/350V - 60c ea. * LCD PHONE DISPLAY: Hitachi $2 * OPTICAL SWITCH: IR LED and detector on one screw mount assy- $2 * DUAL TV ANTENNA: Panasonic extends to over 1 metre - $9.50 *KEY Equipment WANTED DISTORTION TEST SET wanted to buy. Must be auto-nulling and with instruction manuals. Can be Audio Precision, Sound Technology 170x, Hewlett Packard 339 or equivalent standard. If you have one to sell, please contact Leo Simpson on (02) 979 5644 with details and price. St, New Farm, 4004 Old. Phone (07) 358 2785. 16 CHANNEL MIXER: this is the prototype unit, as described in the February to April issues of SILICON CHIP. Complete and going. $850. Phone Leo Simpson on (02) 97_9 5644. BEAM DIVERGING LENS: used in holography etc, - $9.90 * IR FILTERS: 130mm glass $69, 75mm perspex $16.00 * SOLAR PANELS: one watt into 6-8V loads, 150 x 150 x 2.5mm $10 ea. or 10 for $85 * MONOCULAR IR NIGHT VIEWER: complete small scope, plus kit power supply $269.00 * MAINS OPERATED LASER: two used 3mW Siemens tubes plus a new potted mains power supply - $199. * MAINS OPERATED LASER: new 4mW tube plus a potted power supply$249.00 * SILICON SOLAR CELLS: under load deliver 175mAat 0.46V, 12.5 x 50mm - $1 ea.* IR LASER: collimator assembly plus new 5mW 780nm laser diode, plus driver kit - $89. * LCD DIS- Forty pages of dreams! z ID :e JUNE 1992 95 r-------------------------, SILICON CHIP BINDERS l These beautifully-made binders will protect your copies of SILICON CHIP. They feature heavy-board covers and are made from a distinctive 2-tone green vinyl that will look great on your bookshelf. Advertising Index Active Media Images ................. 64 Alpine Technologies .................. 62 Altronics ................ ...... ......... 72-75 Antique Radio Restorations .... .. 94 A-One Electronics ........ ............. 31 * High quality. * Hold up to 14 issues * 80mm internal width. * SILICON CHIP logo printed in gold- Av-Comm .... .. ....................... 34,63 Breakthrough Computers .......... 86 David Reid Electronics ................ 3 Electronic World ........................ 35 Emona Instruments .. .... ............. 55 coloured lettering on spine & -cover. Geoff Wood Electronics ............ 79 Harbuch Electronics .................. 39 Yes! Please send me _ _ _ SILICON CHIP binder(s) at $A11.95 plus $A3 p&p each (NZ $A6 p&p). Hewlett-Packard ................. IFC,59 Enclosed is my cheque/money order for $_ _ _ _ or please debit my Jaycar Electronics ................ 45-52 0 Bankcard O Visa Card O Master Card Hycal Instruments ........ ........ 33,94 J.V. Tuners ................................ 39 Oatley Electronics ...... ............... 95 PC Computers .. ........................ 95 Card No. Pelham ........ .... .......... ................ 95 Signature_ _ _ _ _ _ _ _ _ _ _ Card expiry date_ _ _/_ __ Peter C. Lacey Services ........... 36 Philips Test & Measurement .... . 57 Name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Street _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ RCS Radio ................................ 96 Resurrection Radio .......... .. ......... 9 Rod Irving Electronics .... ...... 10-15 Suburb/town _ _ _ _ _ _ _ _ _ __ Postcode_ _ _ _ __ Rolec Pty Ltd ........................ 22-23 Silicon Chip Back Issues .. ... 88-89 SILICON CHIP PUBLICATIONS PO Box 139, Collaroy Beach, NSW 2097, Australia. Phone (02) 979 5644 Fax: (02) 979 6503. L-------------------------J Silicon Chip Binders ............ .. .... 96 Stewart Electronics ...... ............. 95 St Lucia .... .. .... ......................... .. 54 Tektronix ................................. OBC Telecom .. ................. .... ........ ...... 29 SWITCH: shunt type with two keys - $5 *DYNAMIC MICROPHONE: cassette recorder replacement with lead and 3.5mm plug, 200-600 ohms - $5 * STEREO HEADPHONES: Walkman type, featherweight, high performance - $5 * MAINS FILTERS: in IEC socket, 40 joule varistor supplied - $5 * CRO TUBES: 1-inch electrostatic deflection type CV1522 - $35 * VALVES: 866A $5; 6C6-$5 * IEC EXTENSION LEAD: 2-metres long - $6. • A 10% discount applies on a 10-off purchase of any one of the above items* All of the items listed are new unless stated otherwise * You can obtain an illustrated "flyer" that gives more information on these products. Send stamped SAE. Major cards accepted with phone & fax orders. Certified p&p Australia $5; NZ (via airmail) 96 SILICON CHIP $10. Oatley Electronics, PO Box 89, Oatley, NSW 2223. Phone (02) 579 4985. Fax (02) 570 7910. Transformer Rewinds ............ .... 95 TopCom Communications .. ....... 95 Yokogawa ... .. .. ....... ...... ............ IBC PC Boards Printed circuit boards for SILICON CHIP projects are made by: • Jemal Products, 5 Forge St, Welshpool, WA 6106. Phone (09) 350 5555. RCS Radio Pty Ltd is the only company that manufactures and sells every PC board and front panel published in SILICON CHIP, ETI & EA. • 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 • RCS Radio Pty Ltd, 651 Forest Rd, Bexley, NSW 2207. Phone (02) 587 3491. - -i l' ...----····- ··--Il L___:____ , ''-------·· --L__ ______ r ~ - -- - uu,r ~~5 c-4c4) M~ '128K HE--COHn Lt.. N(.3TI l _ All This Measurement Capability For $6900* Capture and view detailed information over long time intervals easily with the DL 1200's 128k record length and 100Ms/sec sample rate . 300 page Test & Measurement catalogue available Capture up to 4 simultaneous events to speed the analysis of complex digital systems with the Yokogawa DL 1200 YOKOGAWA Worst case jitter measurements become a simple matter using the DL1200's Dynamic Accumulate Mode. Increase your measurement repeatability using the DL 120Ll's Automatic Measurements Call (02) 805 0699 for brochure now! Centrecourt D3 , 25-27 Paul Street North , North Ryde Private Mai l Bag 24 P. O. North Ryde N SW 2113 Phone : (02) 805 0699 Fax : (02) 888 1844 • Pr inter & Memory Card Ext ra