In Reply to: Re: 'Inductance' definition posted by Claude Abraham on October 2, 2003 at 14:42:17:
It is possible to null the internal inductance of the wire..but, to do so requires knowing what is there..If the mu*delta term of inductance is not accounted for, it will be confused with a skin effect phenomena..which is what I feel may have happened to Hawksford..Now, it is actually a tad more complicated than a simple model..
The internal inductance of a wire is dependent on the skin effect, that delta term in the equation of inductance.
So, when trying to null out the internal inductance, it is very possible to do so at one specific frequency..that is because the internal (self) inductance of a wire is VERY dependent on the frequency.. So, to null it out, what's the test frequency??
It's that delta term...frequency dependent, it is..
Now, toss in a high mu material..suddenly, the internal inductance can exceed the actual geometry inductance by two orders of magnitude...now what?
So, how do you make sure you have nulled out the classical, very well known, inductance of the wire? And, when using a test waveform that truncates generating lots of higher frequency harmonic content, what inductance value do you now use?
As I've said, doing this test right is quite a bit more difficult in concept than the article does.
And, the self inductance of any wire is frequency related, thanks to the skin effect. To simply null out a freq. dependent inductance given today's SOTA is not possible, IMHO..yet..there may be tricks that can differentially eliminate it, but that is not clear yet.
Cheers,John
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Follow Ups
- Re: 'Inductance' definition - jneutron 06:07:57 10/03/03 (1)
- Crap..just when it's gettin interesting... - jneutron 18:38:49 10/08/03 (0)