RE: [TCML] Primary selfC

["Lau, Gary" <Gary.Lau@xxxxxx>]

Hi Chris,

The short answer is I don't know of a formula or calculator, but it's relatively easy to actually measure it.

Just as you drive the base of a secondary with a signal generator and monitor a capacitively coupled scope probe for a peak, you can do the same with a primary.  With a known inductance and Fres, you can calculate the Cself.  I think my Fres was about 12 MHz.  I recall that for mine, it wasn't too many pF, and certainly not something that would affect primary tuning.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Chris Swinson
> Sent: Thursday, July 24, 2008 3:59 PM
> To: Tesla Coil Mailing List
> Subject: [TCML] Primary selfC
>
> Hi all,
>
> Does anyone know how to work out , or know of an online calculator for
> crunching primary Self Capacitance ?
>
> I know its not normally needed to know these values, though my tank cap is
> 3nF in my High Q design, and now my primary will be 4 turns of 2" wide strap
> separated about 1mm apart.. the dia is about 22" so its a fair length and it
> could add up to a few hundred pF which is a real problem.. so I need to know
> the values...
>
> Cheers,
> Chris

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