RE: Toroid Capacitance

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

Original poster: "John H. Couture by way of Terry Fritz <teslalist-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Hi D.C. -

I found in the past that when using the JHCTES computer program  the toroid
capacitance reduction will be about 15 to 30 percent of the free space
capacitance. So your 20% is about in the middle of this range. The range I
found covers about 20 years of coiler's TC design and building and a wide
variety of coils and testing. The range also appears to be close to the
reductions found by using Terry's E-Tesla programs, Paul N's TSPP results
and Bart's JAVATC program.

The toroid capacitance reduction is important when using the JHCTES program
to design your coils. If you deduct about 20% from the free space capacity
of the toroid and enter this value into the Secondary Terminal input of the
program the program resonant frequency will be very close to the actual test
frequency.

John Couture

---------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, July 19, 2003 9:58 PM
To: tesla-at-pupman-dot-com
Subject: Re: Toroid Capacitance


Original poster: "Dr. Resonance by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<resonance-at-jvlnet-dot-com>


Yes, we tested a number of toroids last summer for this very factor.  With a
standard toroid load that is 2 x dia. of sec coilform the cap in all cases
was approx 20% of the free measured cap of toroid suspended in air to the
same level as the toroid installed on a coil.  I now sustract 20 % in all my
design work and it hits right on target with measured values.  I used a
variety of toroids, 3x8, 5x26, 34 x 8.5, and 48x12.  20% +- 3% works good
for designs.

We used a scope and measured the freq. shift for various size toroids.

I think it was you who first mentioned this idea to me when I visited you
back in San Diego about 15 years ago.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
  >
  > Have any coilers found that the Toroid free space capacitance is reduced
  > when the toroid is placed on the secondary coil?
  >
  > John Couture
  >