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Re: Characterizing my Secondary



Original poster: "Mike Knowlton" <amdx@xxxxxxxxxxx>

> >I then connected a 100 pf. polystyrene cap. across the coil and
> >found a resonance at 54,081Hz with a Q of 232.

> you can find the Q from the (F2 - F1) / Fo method which I think you know.

Yes the method I use is,
1)  Adjust the signal generator freq. until the scope signal is maximum.
(resonance)
   Record this frequency.
2) Then adjust either the signal generator output level or the scope
variable attenuator
    until the waveform is exactly 7 units high.  (Fo)
3) Vary the signal generator freq up until the scope waveform drops to 5
units.
     Record this freq. (F1)
4)  Vary the signal generator freq down until the scope waveform drops to 5
units
      Record this freq. (F2)
Then compute Fo  /  (F1-F2) = Q

Note: 5 units / 7 units = .714 almost .707  (The 3db points)

                                        Mike K.