Re: Impedance

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Cory,

You may want to check out tonight's post I sent about GM coils.  You need a
solid low-Z signal source that can go up to about 400kHz and a scope with
voltage and current probes.  Then it is really easy!

http://hot-streamer-dot-com/temp/GMCoilTest.jpg

Of course, there is $6000 worth of stuff there =:-O  But you can do it with
far less.  A lot depends on what you have.  A signal source that is the
frequency you want is needed of just about any type as long as the signal
stays as a sine wave.  You then need to measure voltage and current at the
frequency with some accuracy.  Then you just divide to get the impedance.

If you want the complex impedance, then you need to measure the phase shift
and your voltage and current pickups need to be accurate in phase too.
That generally means they have to be able to measure a frequency 10 times
higher.  A sweep frequency generator allows you to see the response
spectrum with is really cool!

http://hot-streamer-dot-com/temp/TekGMT2.gif

I have a color scope with a floppy drive and an HP33120A arb which is nice
for making pretty pictures.  Obviously, I have gotten a little carried away
:o))

In many cases, you may be able to figure it out with circuit simulators
like MicroSim.

http://hot-streamer-dot-com/TeslaCoils/Programs/Programs.htm

So it depends on what equipment you have and such.  Unfortunately, it takes
a scope or a darn good meter and some test equipment.  But the MicroSim
program may do it all for you depending on what you need.  In some cases
(like the GM coil), I may have already done it for you ;-))

Cheers,

	Terry


At 02:24 PM 1/18/2002 -0800, you wrote:
>Hello,
>
>Any good method's for measuring impedance???
>