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AC Resistance Measurements



Hi All,

	I just ordered up one of those fancy HP 34401A multimeters because "I need
it" :-))  It will measure true AC RMS voltage up to 300kHz in the
100.0000mV AC range (6.5 digits).  If I use a resistor in series with a
primary or secondary coil, I may be able to put say 10mA of variable
frequency current through the coil.  The meter should be able to read of
the voltage drop and give me the AC resistance.  With 10mA and 0.1uV of
resolution, I should be able to read AC resistance down to 10 micro-ohms at
normal TC frequencies.  However, there will be radio interference and
resonances and such in the coil that would mess around with such a fine
measurement.  I was thinking of putting some value cap across the coil to
swamp the RFI and lower the resonant frequencies down to where they would
not mess up the measurement.  I was also thinking the same technique could
be used to measure the series resistance of poly caps.

	I think the AC impedances of the coils or caps will make such measurements
impossible.  However, someone may know all about this and could tell me if
it could work or not.  I would be interested in any hints anyone may have
on this. 

	If anyone has any other ideas for useful TC measurements this meter could
do, let me know.  I don't think I'll be measuring the output current of a
neon with it though :-))

Cheers,

	Terry
	terrellf-at-uswest-dot-net