Jasen Betts wrote in a message to Roy J. Tellason:

 RJT> So I should be able to tell with an ohmmeter,  then?

 JB> impedance is a slippery beast... 

Well,  yes...

But from what I can recall,  these things have a FET built into them.  I
was expecting to measure something that'd look like a FET's D-S terminals.

 JB> the answer is yes, with an AC ohmmeter - got one of them?

I could probably whip something up.  

 JB> Try on the 10v scale first see if there's any excitation on the 
 JB> input. many cosumer devices feed a small DC voltage through a 
 JB> large resistor in the input wires to power a 2-wire electret 
 JB> microphone insert.

That's what I was thinking.

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