# [TCML] new toroid capacitance

Bob Wroblewski bwroblewski at yahoo.com
Fri Mar 18 07:34:04 MST 2011

```Hi Rev Fuzzy,

Okay, let's try this again.

The cross sectional area of your toroid ring is about 4.1875 x 2 = 8.375 from
the drawing pdf. So assuming that the area of a circle is determined by  pi
(r^2) and using 8.375 as the desired area, we get 1.633 as an equivalent
circular toroid ring radius or 3.266 as an equvalent circilar toroid ring
diameter.

Assuming that we keep the same 11.75 overall diameter dimension from the drawing
pdf. With an equivalent 3.266 diameter toroid ring we can calculate the two

They are D (maj) 8.484 and D (min) 3.266 for a result of 13.1 pf as calculated
by QTC.xls

That should be good enough as a ballpark figure. Not quite the value you were
hoping for but YMMV.

Regards,
Bob Wroblewski
Dracut, MA

________________________________
From: Reverend Fuzzy <cmayeux at msbministries.org>
To: Tesla Coil Mailing List <tesla at pupman.com>
Sent: Thu, March 17, 2011 11:10:06 AM
Subject: RE: [TCML] new toroid capacitance

Good try, but as stated, this toroid is slightly odd shaped, (as per the linked
diagram), and the spreadsheet you refer to only has
the calculation for a standard toroid shape.  Thanks for trying, though, Bob.
---
Reverend Fuzzy
Pastor, MSB Ministries
Hattiesburg, MS

> -----Original Message-----
> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On Behalf Of
>Bob Wroblewski
> Sent: March 16, 2011 8:39 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] new toroid capacitance
>
> Hi Rev Fuzzy,
>
> Do a web search for QTC.xls then you can save it and use it locally.
> It is a spreadsheet program from Ed Sonderman modified by Ross Overstreet.
I've
> used it quite often over the years. It has a toroid capacitance estimator
based
> on two dimensions of the toroid. My two cents worth. Good luck.
>
> Bob Wroblewski
> Dracut, MA
> ________________________________
> From: Reverend Fuzzy <cmayeux at msbministries.org>
> To: Pupman Tesla List (Pupman Tesla List) <tesla at pupman.com>
> Sent: Tue, March 15, 2011 2:00:47 PM
> Subject: [TCML] new toroid capacitance
>
> I hope someone knows this one... I've made plans for a new toroid, but the
>shape
> is slightly odd, compared to what we've been using.
> I acquired a pair of 2"x11.75" Styrofoam rings (each with one side flat, the
> other side rounded).  My idea is to mount these in a
> 11.75" round section of 3/16" plywood.  Question is, what would be the
>resulting
> capacitance of this topload?  I'm hoping for
> something in the range of 16pf to 26pf, but not holding my breath on that.
>