Hi Neil:
I have a flyback tester that works by counting the ringing.
Shorted turns kill the Q and so this works quite well.
A modified version would simply have a digital display with the
count.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
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Possibly a silly question, but have any Q meters been built that
use the other approach of watching the relaxation decay starting
with a forced excitation and calculating the dissipation factor??
Most of the inductors I'm working with at LF/VLF have a Q of 300
or more, so would it be feasible to resonate one with a very high
performance capacitor, tune a power oscillator to the resonance
peak automatically, then disconnect it at a zero crossing and
capture the decaying oscillation with a fast high impedance ADC
and process it to determine the Q based on the envelope decay??
Indeed, would a single voltage or current pulse suffice as the
excitation rather than an oscillator? A quick simulation suggests
that it is feasible. With a resonance at 150 kHz and a Q of 300,
the envelope amplitude falls to about exp(-pi), around 4%, after 2
ms, or 300 cycles, which is another way to define Q factor.
