On Sun, 7 Dec 2003 19:13:36 +0000, John Woodgate
wrote:

Low-frequency iron-cored coils are quite another matter; the
inductance varies with frequency, voltage, temperature, previous history
and the state of the tide on Europa.

I assume that you are referring to DC biased iron cores (without an
air gap) or some high permeability ferrites with a strong DC bias
current. These do indeed show a variation of inductance depending on
the DC bias current.

Paul OH3LWR