Distributed capacitance effects Q?
On Sun, 29 Apr 2007 18:51:52 -0500, "amdx" wrote:
I gave you a little bit of a trick question when I ask,
The loss in a capacitor would be dielectric and loss in the plates right?
In my inductor the interwinding capacitance is made of a dielectric
(some type of insulation and air) and the plates (made by the wire).
The wire has more current because of that interwinding capacitance,
and as you say "loss is by the square".
Is my argument moving you at all?
Hi Mike,
I'm afraid that if you have expressed an argument, it was lost on me.
Why does the resistance go up near resonance?
I haven't seen that happen.
Try measureing the Q of an aircore coil close to it's self resonance
(or worse, at self resonance without an additional capacitor)
and then at half that frequency.
You have a moving target. Skin effect is shifting as you double/halve
the frequency. What does it mean to compare Q at so disparate
frequencies? Are you exploring an intellectual curiosity or trying to
remedy a defect in application?
However, for the same resistance, as you
approach resonance, the circulating currents climb, and loss is by the
square.
I'm defining circulating currents as those that circulate between turns
and don't necessarily go through the capacitor used to resonate the coil.
Does that fit your definition as used in your paragraph above?
Going between turns can be through a turn-to-turn capacitive coupling,
the magnetic coupling has already been discussed in regard to
increased skin effect due to proximity. Loss still remains the
province of resistance. Your best argument is that Capacitance
exacerbates loss, but it does not cause it.
73's
Richard Clark, KB7QHC
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