Bill Turner wrote:
On 08 Dec 2003 20:09:43 GMT, (Avery Fineman) wrote:
INDUCTANCE doesn't change over frequency
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I maintain it does. Otherwise the formula X=2piFL is invalid.
NO! In the above equation, X varies when F varies. The equation
does NOT mean that L varies as F varies.
Is that
what you're saying?
I understand what you're saying about the inductance of a coil being
fixed and the reactance is the net result of that fixed inductance plus
the effect of the parasitic capacitance between windings, vs frequency,
of course. If one chooses to *model* a coil that way, I have no
objection. You will no doubt arrive at the correct reactance for a
given frequency.
The disagreement here seems to depend on how one defines what inductance
is. I maintain that inductance of a coil is nothing more than the
reactance divided by 2piF, as derived from the formula above. Do you
disagree with that? That formula has been taught for decades. Are you
saying it is wrong?
The formula is fine. Your understanding of it is wrong.
X is inductive reactance.
F is frequency.
L is inductance.
F is a variable, L is fixed and X (the reactance of L at
the frequency) varies as the frequency varies.
--
Bill, W6WRT