# Re: Torroid Formula (To Mark and Jim)

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>
> Original Poster: "MalikAT" <MalikAT-at-holycross.ac.uk>
>

Hi Tab,

Just curious: I understand your developing a Tesla program, but what are you
trying to actually do with Ctop? I'm curious because top capacitance is simple
to calc in a program (as a stand-alone toroid) with 2 inputs:
Ctop(pF) = ((1+(.2781-d2/d1))x2.8)*(sqrt(2pi^2(d1-d2)*(d2/2)/4pi)) for a
toroid.
d1 = diameter of toroid
d2 = diameter of cross section

The problem with Ctop is that once it is placed on the secondary, it appears to
partially lose some of it's capacitance. I'm curious if you are looking into
calcing Ctop based on the coil parameters and if so, what those parameters are.

Thanks,
Bart
>
>
> Hi guys it's Tab,
>         firstly thanks for all your help. I've been trying to do this for
> quite
> some time. Let me fill you in on what i keep getting. (by the way I have
> used the solver function in excel to do this for me, the reason i need to
> do it because i'm writting a computer program to design tesla coils as part
> of my computing course, i've been allowed 1 year to complete it)

(snip)

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