Thread: Winding coils
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Old December 7th 03, 08:04 PM
John Popelish
 
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Bill Turner wrote:

On 07 Dec 2003 18:25:51 GMT, (Avery Fineman) wrote:

Write on the whiteboard 100 times: Inductance does not change
with frequency...reactance changes with frequency.


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Not true. Inductance and reactance are related by the formula
XsubL = 2 pi F L. If XsubL has changed, then so has the inductance, and
vice versa.

How could you possibly define it otherwise?


But the impedance of a coil near resonance is not well described as an
XsubL. It is a combination of XsubL and XsubC, including their
different phase shifts.

You cannot just measure the magnitude of impedance of a coil and
assume that you are measuring pure XsubL. You have to prove that this
is the case by some other measurement, like the phase relationship
between voltage and current.

--
John Popelish