In article , Bill Turner
writes:

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?

I'm saying that the student doesn't understand inductance.

Inductance does NOT vary over frequency for any coil of wire under
its self-resonance.

Reactance varies over frequency with inductance fixed...directly
proportional to frequency. Inductance doesn't vary.

Yes, you can FIND inductance in Henries if you measure its
reactance at a particular frequency. Inductance in Henries has NOT
changed by doing so. Inductance in Henries remains constant.

[feel free to quibble over the spelling of "Henries" v. "Henrys" :-) ]

If your reactance-measuring gizmo is not calibrated properly, then
its readings will show an APPARENT change in inductance. The
inductance still hasn't changed...only the calibration of the gizmo
is off.

Don't get all wound up and take a turn for the worse...

Len Anderson
retired (from regular hours) electronic engineer person