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Re: TC Resonance and Topload Measurements



Original poster: "Kevin Ottalini by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ottalini-at-mindspring-dot-com>

All,
	After checking my setup, I tracked the 60Hz issue
down to an impedance mismatch issue.  In actuality,
the function generator output was being attenuated down
to about 20mVpp at 60Hz, so of course there was no output!
(something about 50 ohms driving 0.100ohms ... go figure!)

I then hooked up a step-down transformer and used my
variac to drive a 1.0Vpp 60Hz signal into the primary
and viola!  I got a slightly trapezoidal, but almost
exactly 1.0 Vpp output from the secondary at the best
coupling position (primary a little less than 1/2 way up
from the bottom of the secondary.

Raising the secondary above the primary does indeed
appear to attenuate as expected, so I should now be able
to get a coupling test run for ACMI (just a little more
cleanup).

(Thanks for your restraint Terry ... I knew your setup was
working ... I'm just used to the $13,000.00 HP variable 
impedance function generators at work and so of course I
expected my $500 B&K to act the same way).

Best,
	Kevin

> Original poster: "Kevin Ottalini <ottalini-at-mindspring-dot-com>
> 
> All:
> 	I just completed a small coil setup specifically
> to test resonance with and without a topload, and coupling
> between primary and secondary.
> 
> Rather than use the 60Hz high-current method that Terry,
> et. al. have been using for the ACMI testing, I instead
> used my Tek Oscilloscope and B&K function generator to
> check behavior at 60Hz as well as at higher frequencies.
> 
> Although it was my intent to verify the 60Hz behavior, I
> found that I was unable to get any significant coupling
> with a 60Hz sinewave running at 1Vpp and at 10Vpp what I
> saw could only be regarded as 60Hz patterned noise.
> 
> (My apologies Terry!)