Measureing Q of a pi tank circuit
 

On Sat, 04 Sep 2004 14:15:12 -0700, Bill Turner
wrote:

Is there a way to actually measure the Q of a pi tank circuit as used in
a tube type amplifier? I know how to calculate it, but I'd like to be
able to measure it in a real circuit.

I'd like to use an SWR analyzer on the 50 ohm side, put an equivalent
resistance on the tube side, adjust C1 and C2 for a 1:1 match, and then
vary the frequency and observe how the SWR changes.

I'm sure there must be a way to correlate the SWR bandwidth with Q, but
I'm not enough of a mathematician to do it.

Presumably the Q correlates to the TC's shape factor. You could
measure/easily calculate that from just sweeping a signal source
though the TC and measuring the relevant -3dB and (-50dB) signal
levels with a 'scope?
--

"What is now proved was once only imagin'd." - William Blake, 1793.