[TCML] inductance vs. current in a RF inductor

[DC Cox <resonance@xxxxxxxxxxxx>]

What is inductance?

I is NOT based on the general rule for inductive reactance. It goes back
beyond that to Faraday's Laws of Induction.

It is all based on counter EMF arising from Faradays law --- the counter EMF
generated to oppose a given change in current. The unit of inductance from
the equation is:


L= Volt second / Amps = Henry

Notice that this fundamental physics equation derives inductance from
Amperes.  In a RF inductor the current is constantly changing, the Q is
contantly changing, and
the inductance is constantly changing.

You can't set a pot to one value and expect it to produce zero crossing for
differing values of current.  Unless you dynamically track it, or perhaps
alter it with
a delay line, Zap's circuit won't work properly.  It does allow zero cross
settings, but for only one phase of the signal and one particular point of
current amplitude --- not across the entire signal range.

The current is changing, the Q is changing, and hence the inductance is
changing.

Dr. Resonance
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