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distributed capacitance measurement?




From: 	bmack[SMTP:bmack-at-frontiernet-dot-net]
Sent: 	Wednesday, September 03, 1997 10:09 PM
To: 	tesla list
Subject: 	distributed capacitance measurement?

To All,

How the heck do you MEASURE the distributed capacitance
of a secondary?

I have a several methods to determine f-res and Q, but don't
have a clue how you can separate the system into L and C for
true empirical measurement.
Unless you are calculating it from the approximate known value
of L when resonance is determined? Thats what I use,-but that's
NOT a measurement. 

Another indirect method might be to use lisajous figures on a 
scope to determine the 45 degree point in a LR circuit (the R
being a variable) at a low and high freqency ( below Fr).  the
reactance difference would represent it's distributed capacitance,
at the higher freq used. For best results, get close to Fr.
As you know, all electronic component values are frequency 
dependent-even resistors!  The problem gets worse as one progesses
upward into hf -the uper limit for Tesla coils.

The last paragraph is pure speculation on my part. Has anyone tried this?

Thanks in advance
Jim M