Re: capacitance of horned toroid

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:
 >
 > Original poster: "Godfrey Loudner" <ggreen-at-gwtc-dot-net>
 >
 > Hello Antonio
 >
 > refer to http://www.pupman-dot-com/listarchives/2004/February/msg01419.html and
 > http://www.pupman-dot-com/listarchives/2004/March/msg00164.html.
 > I have not yet heard back from NASA, so I went ahead with
 > my own developments.
 >
 >...
 >
 > So the best so far in the MKS system of units is
 >
 > C = 8(permittivity)(1.3677)d.
 >
 > Your previous calculation with d = 0.4999, gave C = 48.43867pF.
 > My calculation gives C = 48.42980pF.
 >
 > BTW, Bert Pool's formula gives 38.00029pF. It surely breaks
 > down when (D-d)/d is close to 1.

For 1x0.4999, I get:
Legendre:                  48.4368795055 pF (correct to the last digit)
Simulation with 200 rings: 48.4368723122 pF
Your formula:              48.4298028145 pF

For 1x0.5:
Legendre:                  does not converge
Simulation with 200 rings: 48.4386640438 pF
Your formula:              48.4394907126 pF

The formula:
100e-12*(0.37*D+0.23*d) pF
gives 48.4977000000 pF for 1x0.4999 and 48.5000000000 pF for 1x0.5.
Not bad.

Antonio Carlos M. de Queiroz