Re: capacitance equation for toroids

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

Original poster: "Mark Broker by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mbroker-at-thegeekgroup-dot-org>

Dan, I think you should look at the equations again....

d/D > 0.25:  Cpf = (0.94 *d) + (0.584 * d)

d/D < 0.25:  Cpf = 4.57 * (D-d) / ln (8 * (D-d) / d))
Another simple equation, although not as accurate (but close for most 
sizes) is:

Cpf = D + d / 2.56

For a sphere the equation is Cpf = 1.4 * dia.


Let D = 1m (~39in), d = 10cm (~3.9in):
Cpf = 4.57 * (1-.1) / ln (8 * (1-.1) / .1)  = .96pF
Cpf = 4.57 * (39-3.9) / ln (8 * (39-3.9) / 3.9) = 37.5pF

Wintesla gives 34.2pF

I'd say the units are inches ;)


One error Dr. R's equations: the first equation should really be:
Cpf = (0.94 * D) + (0.584 * d)
             ^^^

Regards,

Mark Broker
Chief Engineer, The Geek Group


On Fri, 06 Jun 2003 10:20:30 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:

>Original poster: "Mccauley, Daniel H by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>
>
>It doesn't matter its a ratio.
>Dan
>
>
>
> > Hi Doc!
> >
> > Is that measured in inches, meters, cubits, furlongs, or
> > nautical miles? ;-)
> >
> >
> > Matt D.
> >
> >
>