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Let's drop in
on Wily and look over his shoulder at his latest project.... |
Solar Powered Wireless
Sensor |
Wily had just
returned from his morning walk when he got a call from a company in sunny
Florida. The company was desperate. They needed a DC power
supply for a remote sensor they were developing for one of their larger
customers. The sensor was connected to a low power microprocessor and
a RF transmitter. When switched on, collected data was quickly
transmitted in a short burst. The transmitter drew a peak current of 1
Amp for about 0.01 seconds from a 3v supply. The transmitter was
turned on only once every 10 seconds. his worked out to an average
current from the +3v supply of only 1ma. The sensor and processor
added only another 0.1ma of average current...... |
con't page
7 |
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WHAT THE WORLD NEEDS NOW is . NiMH
Battery
Tester |
Rechargeable NiMH
batteries are used in countless electronic products. These
batteries make economic sense since one set of rechargeable batteries can be
charged and discharged 100s of times instead of throwing away a depleted set
of non-rechargeable types each time. There are lots of AA and AAA NiMH
battery chargers available. Some are designed to quickly charge a
battery in as little as 15 minutes. Although there are lots of ways to
charge these batteries there is no easy way to test them. How do you
know if the 3-year-old batteries you have been using are ready for the
recycle bin? If you discover that the 4 AA cells which you use in a
digital camera run out of juice after only a few shots, you know that there
is one or more of the 4 cells which is bad, but which ones? |
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story con't on page 6 |
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Yellowstone
Might Explode
By: Dave Johnson
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The
geology at Yellowstone National Park, here in the U.S., is complex.
The whole area is one big volcano. In fact, some geologist think it might be
the largest one on earth. It appears that the Yellowstone super
volcano blows its top every 600,000 years. The last time the place erupted
was some 650,000 years ago. In other words, it is due for
another volcanic event. This event could be a really bad one. ..... |
story con't on page 8 |
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New Products 2009
New product announcements are made nearly every
day. I subscribe to many trade journals and each is filled with
hundreds of flashy advertisements. But, only a few of those product
ads catch my eye. Since I’m a circuit designer, I especially like
those components that trigger many new application ideas in my mind.
Sometimes it is the smallest products that are the most useful. I
often discovered new products in surplus electronic catalogs. The
surplus companies often buy up stock that came from companies that went out
of business. Bad marketing or bad management may have killed a
perfectly good product idea. Their loss can be your gain if you can
spot the bargain.
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Measuring Low
Value Resistors
By: Dave Johnson
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Most multimeters are
only good down to about plus or minus one half ohm in accuracy. In many
switch mode power supplies and in high current sensors, you would like to know
the resistance of a piece of wire, an inductor or a shunt resistors down to
perhaps 0.0001 ohm. When I need to accurately measure the resistance of
such a device, I reach for my handy 1 Amp current injector device.... |
story con't on page 4 |
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Dirty PC Boards
by David Johnson, P.E.
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Several years ago I received a
frantic call from one of my clients. He was having all kinds of problems
with some new railroad ice detector units he was building. I had
designed the system for him, so I was quite familiar with the circuit.
He said that there were not just one symptom but instead, there are all kinds.
None of the units would work and some behaved very erratically. It was a
common practice for me to build the first 20 or so units, to make sure that
the overall design was.... |
story
con't on page
3 |
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Bad Computer Power Supplies |
For the last 10 years of so, I
have built my own computers. I buy the needed components and assemble
them in a metal computer tower case similar to the one shown below. I
feel that this gives me more control of my computer than buying a complete
system from a store. However, I have learned the hard way that the
typical computer power supply that often comes with the tower case is not
worth using. |
story con't
on page 5 |
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Energy Savings
Using Voltage Bucking Transformer |
I
have read that some people have installed a large inductor in
series with their home’s electrical supply to help reduce power
consumption. The idea is that the inductor would have the
effect of lowering the AC voltage by shifting the phase
relationship between voltage and current. Could such a
device really reduce power consumption and how much would it
save?..... |
story con't on page 2 |
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