Silicon ChipWatch those resistors: they may not be what they seem - July 1989 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: Watch those resistors: they may not be what they seem
  4. Feature: A Day In The Lfe Of A Computer by Ross Phillips
  5. Project: Exhaust Gas Monitor For Cars & Vans by Bob Flynn & Leo Simpson
  6. Vintage Radio: Old Henry: one of my favorites by John Hill
  7. Project: Extension For The Touch-Lamp Dimmer by Leo Simpson
  8. Project: Experimental Mains Hum Sniffers by Steve Payor
  9. Serviceman's Log: You need a pal to deal with PAL by The TV Serviceman
  10. Project: Compact Ultrasonic Car Burglar Alarm by Greg Swain
  11. Feature: Amateur Radio by Garry Cratt, VK2YBX
  12. Feature: Computer Bits by Jennifer Bonnitcha
  13. Feature: The Way I See It by Neville Williams
  14. Feature: The Evolution of Electric Railways by Bryan Maher
  15. Subscriptions
  16. Back Issues
  17. Market Centre
  18. Advertising Index
  19. Outer Back Cover

This is only a preview of the July 1989 issue of Silicon Chip.

You can view 44 of the 96 pages in the full issue, including the advertisments.

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Items relevant to "Experimental Mains Hum Sniffers":
  • Silicon Chip article scan, July 1989 - Experimental Mains Hum Sniffers (AUD $10.00)
Articles in this series:
  • Amateur Radio (November 1987)
  • Amateur Radio (December 1987)
  • Amateur Radio (February 1988)
  • Amateur Radio (March 1988)
  • Amateur Radio (April 1988)
  • Amateur Radio (May 1988)
  • Amateur Radio (June 1988)
  • Amateur Radio (July 1988)
  • Amateur Radio (August 1988)
  • Amateur Radio (September 1988)
  • Amateur Radio (October 1988)
  • Amateur Radio (November 1988)
  • Amateur Radio (December 1988)
  • Amateur Radio (January 1989)
  • Amateur Radio (April 1989)
  • Amateur Radio (May 1989)
  • Amateur Radio (June 1989)
  • Amateur Radio (July 1989)
  • Amateur Radio (August 1989)
  • Amateur Radio (September 1989)
  • Amateur Radio (October 1989)
  • Amateur Radio (November 1989)
  • Amateur Radio (December 1989)
  • Amateur Radio (February 1990)
  • Amateur Radio (March 1990)
  • Amateur Radio (April 1990)
  • Amateur Radio (May 1990)
  • Amateur Radio (June 1990)
  • Amateur Radio (July 1990)
  • The "Tube" vs. The Microchip (August 1990)
  • Amateur Radio (September 1990)
  • Amateur Radio (October 1990)
  • Amateur Radio (November 1990)
  • Amateur Radio (December 1990)
  • Amateur Radio (January 1991)
  • Amateur Radio (February 1991)
  • Amateur Radio (March 1991)
  • Amateur Radio (April 1991)
  • Amateur Radio (May 1991)
  • Amateur Radio (June 1991)
  • Amateur Radio (July 1991)
  • Amateur Radio (August 1991)
  • Amateur Radio (September 1991)
  • Amateur Radio (October 1991)
  • Amateur Radio (November 1991)
  • Amateur Radio (January 1992)
  • Amateur Radio (February 1992)
  • Amateur Radio (March 1992)
  • Amateur Radio (July 1992)
  • Amateur Radio (August 1992)
  • Amateur Radio (September 1992)
  • Amateur Radio (October 1992)
  • Amateur Radio (November 1992)
  • Amateur Radio (January 1993)
  • Amateur Radio (March 1993)
  • Amateur Radio (May 1993)
  • Amateur Radio (June 1993)
  • Amateur Radio (July 1993)
  • Amateur Radio (August 1993)
  • Amateur Radio (September 1993)
  • Amateur Radio (October 1993)
  • Amateur Radio (December 1993)
  • Amateur Radio (February 1994)
  • Amateur Radio (March 1994)
  • Amateur Radio (May 1994)
  • Amateur Radio (June 1994)
  • Amateur Radio (September 1994)
  • Amateur Radio (December 1994)
  • Amateur Radio (January 1995)
  • CB Radio Can Now Transmit Data (March 2001)
  • What's On Offer In "Walkie Talkies" (March 2001)
  • Stressless Wireless (October 2004)
  • “Degen” Synthesised HF Communications Receiver (January 2007)
  • WiNRADiO: Marrying A Radio Receiver To A PC (January 2007)
  • PICAXE-08M 433MHz Data Transceiver (October 2008)
  • Half-Duplex With HopeRF’s HM-TR UHF Transceivers (April 2009)
  • Dorji 433MHz Wireless Data Modules (January 2012)
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)
Articles in this series:
  • The Way I See It (November 1987)
  • The Way I See It (December 1987)
  • The Way I See It (January 1988)
  • The Way I See It (February 1988)
  • The Way I See It (March 1988)
  • The Way I See It (April 1988)
  • The Way I See It (May 1988)
  • The Way I See It (June 1988)
  • The Way I See it (July 1988)
  • The Way I See It (August 1988)
  • The Way I See It (September 1988)
  • The Way I See It (October 1988)
  • The Way I See It (November 1988)
  • The Way I See It (December 1988)
  • The Way I See It (January 1989)
  • The Way I See It (February 1989)
  • The Way I See It (March 1989)
  • The Way I See It (April 1989)
  • The Way I See It (May 1989)
  • The Way I See It (June 1989)
  • The Way I See It (July 1989)
  • The Way I See It (August 1989)
  • The Way I See It (September 1989)
  • The Way I See It (October 1989)
  • The Way I See It (November 1989)
  • The Way I See It (December 1989)
Articles in this series:
  • The Evolution of Electric Railways (November 1987)
  • The Evolution of Electric Railways (December 1987)
  • The Evolution of Electric Railways (January 1988)
  • The Evolution of Electric Railways (February 1988)
  • The Evolution of Electric Railways (March 1988)
  • The Evolution of Electric Railways (April 1988)
  • The Evolution of Electric Railways (May 1988)
  • The Evolution of Electric Railways (June 1988)
  • The Evolution of Electric Railways (July 1988)
  • The Evolution of Electric Railways (August 1988)
  • The Evolution of Electric Railways (September 1988)
  • The Evolution of Electric Railways (October 1988)
  • The Evolution of Electric Railways (November 1988)
  • The Evolution of Electric Railways (December 1988)
  • The Evolution of Electric Railways (January 1989)
  • The Evolution Of Electric Railways (February 1989)
  • The Evolution of Electric Railways (March 1989)
  • The Evolution of Electric Railways (April 1989)
  • The Evolution of Electric Railways (May 1989)
  • The Evolution of Electric Railways (June 1989)
  • The Evolution of Electric Railways (July 1989)
  • The Evolution of Electric Railways (August 1989)
  • The Evolution of Electric Railways (September 1989)
  • The Evolution of Electric Railways (October 1989)
  • The Evolution of Electric Railways (November 1989)
  • The Evolution Of Electric Railways (December 1989)
  • The Evolution of Electric Railways (January 1990)
  • The Evolution of Electric Railways (February 1990)
  • The Evolution of Electric Railways (March 1990)
SILICON CHIP Publisher & Editor-in-Chief Leo Simpson, B.Bus. Editor Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke , B.E.(Elec.) Robert Flynn Advertising Manager Paul Buchtmann Regular Contributors Neville Williams , FIREE, VK2XV Bryan Maher, M.E. B.Sc. Jim Yalden , VK2YGY Garry Cratt, VK2YBX Jim Lawler, MTETIA John Hill David Whitby Photography Bob Donaldson Editorial Advisory Pane l Philip Watson, MIREE, VK2ZPW Norman Marks Steve Payor, B.Sc., B.E . SILICON CHIP is published 1 2 times a year by Silicon Chip Publications Pty Ltd . All material copyright (c) . No part of the contents of this publication may be reproduced without prior written consent of the publisher. Kitset suppliers may not photostat articles without written permission of the publisher. Typesetting/makeup: Magazine Printers Pty Ltd, Waterloo , NSW 2017 . Printing: Masterprint Pty Ltd, Dubbo, NSW 2830. Distribution: Network Distribution Company. Subscription rate: currently $42 per year (12 issues) inside Australia. For overseas rates, refer to the subscription page in this issue. Liability: Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. Address all mail to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy Beach , NSW 2097. Phone (02 ) 982 3935. ISSN 1030-2662 * Recommended and maximum Australian price only. 2 SILICON CHIP PUBLISHER'S LE't-1ER Watch those resistors: they may not be what they seem Are you fully familiar with the resistor colour codes? Both the 4•band and the 5-band codes? For many years the first and biggest hurdle for the budding electronics enthusiast was to learn the colour code. Nowadays it is a lot easier because you can bypass the need to learn the colour codes by just using a digital multimeter. And if you are using close tolerance (eg, 1 % ) resistors with a 5-band code, trying to read the colours can be a bit of a pain. Why go through the mental gymnastics of translating the colour code when you can just whack the resistor across the multimeter and read off the value? If you are an enthusiast of several years' standing you may be rather disdainful of people who have to resort to a multimeter to check resistor values. Can't these people do a little mental arithmetic? After all, after you have acquired a little familiarity with the colour code, reading off resistor values becomes second nature, doesn't it? We happen to think that readers who are new to electronics do find reading colour codes difficult. So we are now listing the colour codes of every resistor specified in project articles. As well, in the first article of our ongoing series ''Electronics for Everyone'' , we recommended the use of a digital multimeter to check resistor values. We now believe, that with the vast numbers of Asian-sourced resistors on the market, that all resistors must be checked for value before use. Never mind what the colour code says, you still have to check the value. If you persist with the idea that you can read the colour codes and therefore you don't need to check values, you could be headed for trouble. In our recent experience, the colours don't mean much at all. For some time, it has been easy to confuse red bands with orange and green with grey but now it's worse. An orange band may really be yellow and what you think is a brown band could well be red. Only this morning, I soldered what I would have sworn was an 18k0 resistor into circuit only to have it malfunction. The resistor was actually 180k0 and yet the third colour band was unmistakably orange! It's about time the importers of these resistors did something about the colour codes. Why can't they be made to agree with those made by long established makers like Philips? Or is the reason really that the Asian makers don't know the colour code either? Anyway, you have been warned. Check those resistors with your multimeter before soldering them into circuit. Leo Simpson