This is only a preview of the October 2009 issue of Silicon Chip. You can view 32 of the 104 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "High-Quality Stereo Digital-To-Analog Converter, Pt.2":
Items relevant to "Digital Megohm & Leakage Current Meter":
Items relevant to "Using A Wideband O₂ Sensor In Your Car, Pt.2":
Articles in this series:
Purchase a printed copy of this issue for $10.00. |
SILICON
SILIC
CHIP
www.siliconchip.com.au
Publisher & Editor-in-Chief
Leo Simpson, B.Bus., FAICD
Production Manager
Greg Swain, B.Sc. (Hons.)
Technical Editor
John Clarke, B.E.(Elec.)
Technical Staff
Ross Tester
Jim Rowe, B.A., B.Sc
Mauro Grassi, B.Sc. (Hons), Ph.D
Photography
Ross Tester
Reader Services
Ann Morris
Advertising Enquiries
Glyn Smith
Phone (02) 9939 3295
Mobile 0431 792 293
glyn<at>siliconchip.com.au
Regular Contributors
Brendan Akhurst
Rodney Champness, VK3UG
Mike Sheriff, B.Sc, VK2YFK
Stan Swan
SILICON CHIP is published 12 times
a year by Silicon Chip Publications
Pty Ltd. ACN 003 205 490. ABN 49
003 205 490. All material is copyright ©. No part of this publication
may be reproduced without the written consent of the publisher.
Printing: Hannanprint, Noble Park,
Victoria.
Distribution: Network Distribution
Company.
Subscription rates: $94.50 per year
in Australia. For overseas rates, see
the order form in this issue.
Editorial office:
Unit 1, 234 Harbord Rd,
Brookvale, NSW 2100.
Postal address: PO Box 139,
Collaroy Beach, NSW 2097.
Phone (02) 9939 3295.
Fax (02) 9939 2648.
E-mail: silicon<at>siliconchip.com.au
ISSN 1030-2662
* Recommended and maximum price only.
2 Silicon Chip
Publisher’s Letter
Oscilloscope probes are a vital
link in looking at signals
In all fields of electronics, the oscilloscope is regarded
as the tool of choice. It gives you a means of looking at
a vast range of signals, both analog and digital, audio,
radio and higher frequencies. While you can always take
voltages around a circuit, the oscilloscope will give a
clear indication of whether the device is actually working, whether it has a fault condition or whether it is dead.
Even if a circuit appears to be working perfectly, an
oscilloscope can reveal if it has problems with a tendency
to supersonic oscillation, for example, or whether it has overshoot, under-shoot,
unduly long settling times or whatever.
No wonder technicians and engineers regard the oscilloscope as being so indispensable. Without it, you are virtually blind and you are forced into proxy methods to determine whether a circuit is working or not. And yet, most people using
oscilloscopes are quite cavalier in their use of probes. This is odd, because if you
do not understand and use oscilloscope probes correctly, you can greatly degrade
the quality of your observations. In short, you can turn an expensive wideband
oscilloscope into a very ordinary instrument.
Which is why we are pleased to feature this month’s article on oscilloscope
probes by Doug Ford. It gives a very good description of how scope probes work,
moving from the over-simplified explanation that is commonly quoted in textbooks
and technical articles to a more detailed description of their operation as transmission lines. In fact, it demonstrates that there is far more technology involved
in high-performance probes than you would think. So that’s why they can be so
expensive to replace!
Rational climate change debate has yet to take hold
We are also very pleased to feature a long letter from Professor Ian Plimer in the
Mailbag pages, on the subject of climate change. While many readers are probably
sick of seeing references to the subject, we are extremely worried that moves to an
emissions trading scheme (ETS), renewable energy targets (RET) and carbon pollution reduction scheme (CPRS) are extremely ill-conceived, will be expensive to
implement and ultimately, will have zero effect on either carbon dioxide emissions
from power stations, cars or any other human activity. Furthermore, they will have
no effect on global warming, if in fact, it is still occurring or if it is anthropogenic
(ie, caused by man’s activities) – itself unknowable at this stage of our knowledge
on long-term climate.
However, in virtually all of the debate on these measures, it seems to be accepted
by most politicians and most of the media that global warming is definitely happening and furthermore, that it will be bad and must be stopped. Anyone that does
not hold that view is likely to be pilloried as a “denier”, a ratbag or with epithets
that are much worse. For example, Senator Steve Fielding has been ridiculed for
asking why global warming has apparently stopped when carbon dioxide continues
to rise. Yet Steve Fielding is no fool and is a qualified engineer.
Professor Plimer’s book demonstrates that there are vast mechanisms at work
which control our climate, virtually none of which are discussed in the popular
panic over climate change. Nor is he the only one who promotes the view that man’s
activities have negligible effect on our climate. There are thousands of scientists
who agree with him.
The sooner that politicians and the media take these contrary views more seriously, the better off we will all be.
Leo Simpson
siliconchip.com.au
|