# Re: I am Dr. Megavolt

• To: tesla-at-pupman-dot-com
• Subject: Re: I am Dr. Megavolt
• From: Terry Fritz <twftesla-at-uswest-dot-net>
• Date: Wed, 06 Sep 2000 18:59:37 -0600
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

```At 05:21 PM 9/6/00 -0700, you wrote in part:

>One of the best ways for calculating the top electrode
>voltage is to take the stored energy in the primary cap
>and and transfer it in the top electrode capacitance.
>Assuming that about 75% of the input energy makes it to
>the output, the equation is simply:
>
>  [1/2 * Cp * Vp^2] * 75%  =  1/2 * Cs * Vs^2
>

Hi Greg,

This equation could be re written to:

Vs = Vp x SQRT(Cp/Cs) x SQRT(0.75)

Which can be equivalent to:

Vs = Vp x SQRT(Ls/Lp) x SQRT(0.75)

Which is:

Vs = 0.866 x SQRT (Ls/Lp)

"i" usually estimate the secondary voltage as:

Vs = 0.5 x SQRT (Ls/Lp)

For most small coils, I am fairly confident that "the factor" is 0.5 to 0.6

If your are fairly confident that the factor is "around" 0.87 for your
"really big" coils, (that the rest of us can only dream of ;-)) it would
provide an interesting comparison of the efficiencies of large coils vs.
smaller coils...

Cheers,

Terry

```