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Re: Torroid Capacitance

>>From EDHARRIS-at-MPS.OHIO-STATE.EDU Mon Mar  4 01:16 MST 1996
>From: EDHARRIS-at-MPS.OHIO-STATE.EDU
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>Date: Mon, 04 Mar 1996 00:11:50 -0500 (EST)
>Subject: Torroid Capaciatance
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>	Since there was some recent discussion on the capacitances of 
>torriods, I dug up a formula from W R SMYTHE in his text "Static and 
>Dynamic Electricty". The formula is listed in exercise problem 119 in 
>chapter 5. It is a series expansion  for a torriod in free space. 
>Unfortunately, it may be of little practical value (for coilers) since the 
>capacitance is drasically modified by the presence of the coil (and 
>possibly ground). I don't list the formula here since it would tax my ascii 
>art skills.
>
>-Ed Harris
>
>
Hello Ed and other interested coilers,
        I looked at Smythe's text last night.  Nice infinite series
expansion of Legendre functions.  As you pointed out, his formula applies to
a toroid in free space, without a central conducting disk and without the
influence of a nearby conducting helical resonator.  I tend to favor Bert
Poole's empirical formula, since it has provided close results for the two
toriods I have built so far.  Interesting formula nonetheless.  There is a
lot of useful tidbits in that text, if you can sift through it.
Regards,
Mark S. Rzeszotarski, Ph.D.