Hi Roy.

08-Nov-03 12:06:17, Roy J. Tellason wrote to Matt Mc_Carthy

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

impedance is a slippery  beast... the answer is yes, with an AC
ohmmeter - got one of them?

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

electret inserts have a fairly high impedance

FWIW feedign a 1000 ohm electriet with it's excitation voltage theough a 1500
ohm resistor resuults in a device with 600 ohm impedance

but unless you need hi-fidelity impedance matching etc isn't all that
important. standard headphones will work as a microphone...

 RJT> Know of any pointers to info regarding the impedances,  levels,
 RJT> etc. for typical sound card inputs and outputs

 -=> Bye <=-

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