Bill Turner wrote:

Your point is well taken, but look at it this way:

Say I give you a black box containing an inductor with two terminals on
the box. If I have you measure the inductance at one and only one
frequency, there is no way for you to know whether it is an inductor
operating well below its self-resonance point, or an inductor operating
near its self-resonance point. To the outside world, at ONE frequency,
they appear identical; same reactance, same inductance.

Not if I can measure both the magnitude and phase relationship of the
device.

If I can only measure the magnitude of impedance at one frequency, I
can't even tell if the device is predominately inductive, capacitive
or resistive. So it would be a bit silly to call that magnitude an
inductive impedance.

And yet, at some other (lower) frequency, they will measure quite
differently. This is the basis for my observation that inductance does
indeed vary with frequency, based on the parasitic capacitance present
in all inductors.

Only because you are willing to confuse complex impedance with
inductive reactance.

And yes, if you can factor out the self-capacitance, then the inductance
would indeed be constant with frequency. The problem is, no one has
ever figured out how to do that with an actual coil. It can't be done.

You are projecting your limitations onto others.

--
John Popelish