Re: super cheap capacitance/inductance Tesla coil metering - Software

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:

> Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
> I have been playing with this idea...
> The sound cards tend to only be good for 100 to 10,000Hz and they 
> are real digital choppy.  The program are "ok" if you have used 
> those tools before.  But they are pretty nasty for someone whose has 
> never used a scope or generator or "windows"......
> I am now not sure much real good can be done between 100 and 10kHz...
> It makes cheaper digital meters look like a real good deal ;-))
> The program at:
> http://www.marchandelec.com/fg.html
> Is cool since it has the free source code.  But it is way beyond me...

It's surely possible to make a capacitance meter using the sound card,
with a minimum of extra components. One of the best methods for measuring
inductances or capacitances is to look at the resonance frequency of a
series LC circuit, where one of the elements is known. This requires
a sinusoidal generator of known frequency, that can be programmed at
the sound card output (add a resistor in series to connect the output
to the LC circuit, if the output impedance is too low), and something
to measure the voltage over the LC circuit, that can be programmed
using the sound input. There are many other possibilities, as just
looking at the ringing frequency when a high-Q RLC circuit is excited
by a step.

Antonio Carlos M. de Queiroz