[Amps] Measuring tank coil inductance

Bill Turner dezrat1242 at yahoo.com
Fri Apr 26 01:56:17 EDT 2013


ORIGINAL MESSAGE (may be snipped): 
On Thu, 25 Apr 2013 21:44:38 -0700, K2VCO wrote:

>I have learned that to use the AADE successfully you have to disconnect everything from 
>the component you are testing!

REPLY: 
Yes and no. 

In the case of the tune cap, you also need to include the tube's output
capacitance and any stray capacitance to ground. But you MUST disconnect the
plate choke since it is a very low impedance at the audio frequencies the
AADE unit uses, so you will be measuring the capacitance all the way through
it including the bypass cap at the bottom. 

In the case of the output cap, you need to disconnect the coax leading to
the output jack or relay. At the AADE frequencies, coax looks like a
capacitor rather than a section of transmission line. 

Bill, W6WRT


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