# Re: Secondary Resonance LC and Harmonics

• To: tesla@xxxxxxxxxx
• Subject: Re: Secondary Resonance LC and Harmonics
• From: "Tesla list" <tesla@xxxxxxxxxx>
• Date: Tue, 28 Jun 2005 16:35:12 -0600
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• Delivered-to: tesla@pupman.com
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• Resent-date: Tue, 28 Jun 2005 16:48:56 -0600 (MDT)
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Original poster: FIFTYGUY@xxxxxxx

In a message dated 6/27/05 1:55:18 PM Eastern Daylight Time, tesla@xxxxxxxxxx writes:
We can examine the classic equation for an air cored inductor: L = u
Nsqrd A / l
Multiply the numerator and denominator by 4pi we get:

`L = u Nsqrd 4pi sqrd  r sqrd / 4 pi l  =  u (2pi r N)sqrd / 4 pi l`

`Since 2pi rN equals wire length we can write:`

`L = u (wire length)sqrd / 4 pi l`

```Letting the solenoid height ( l ) equal the wire length,  we find
that the classic equation predicts that the inductance of a straight
wire is simply:```

`Lstwire = u wire length / 4 pi`

But using the above "classic equation" also collapses the inductance to zero as the radius "r" and the turns "N" go to zero.

`-Phil LaBudde`