Re: Secondary Q's and magnets
Subject: Re: Secondary Q's and magnets
From: ed-at-alumni.caltech.edu (Edward V. Phillips)
Date: Tue, 12 Dec 1995 20:25:37 -0800
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Bet you are way under measuring your Q! Were you
allowing for the series resistance of the signal generator?
In my similar measurements here I load the signal generator
with 10 ohms, and still find that the voltage tends to dip
significantly as I tune it to the series resonant frequency
of poorer coils than yours must be. I use a small piece
of PC board material about 1" square on the probe, and ground
it through a combination of a 10 mH RF choke and a 10 k resistor
in series. The latter gets rid of the problem of 60 cycle pickup,
and I get plenty of sensitivity with the 0.1 volt/division
gain of the scope.
Not sure where the difference (small, even if consistent)
in resontant frequencies comes from.
Bottom line is that I would expect the Q to be closer to
320 than to 32.