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Re: Capacitance of a long thin rod (e.g. a spark) (fwd)
---------- Forwarded message ----------
Date: Fri, 17 Jul 1998 07:29:19 +0000
From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Capacitance of a long thin rod (e.g. a spark) (fwd)
Jim -
If the capacitance of the TC secondary is changed by the streamers
wouldn't this put the system out of tune and stop the streamers?
Richard Hull said it was an extreme change implying much more than 5%. He
did not say how he measured the frequencies with and without streamers under
high voltage operating conditions.
John Couture
---------------------------------------------------
At 09:44 PM 7/15/98 -0600, you wrote:
>
>
>---------- Forwarded message ----------
>Date: Wed, 15 Jul 1998 10:15:39 -0700
>From: Jim Lux <James.P.Lux-at-jpl.nasa.gov>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: Capacitance of a long thin rod (e.g. a spark)
>
>An equation you may find handy for addressing the issue of the change in
>capacitance (and hence resonant frequency) of the secondary due to a
>spark emerging from the top is:
>
> C = 2 * pi* epsilon0 *length / ln(length/radius)
> = .555 * length (cm) / ln(length/radius) pF
>
>For a 1 meter spark (100 cm) with a radius of .01 cm, the capacitance
>is:
>
> = .555 * 100 / ln (100/.01) = 55.5/9.2 = 6 pF
>
>This is a pretty significant change out of a total secondary C of 50 pF
>or so.... (a 5% change in frequency)
>
>