Re: Toroid Capacitance

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

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



20% works good if the toroid to sec. coilform is near or slightly larger
than a 2:1 diameter ratio.

Dr. Resonance

 >
 > 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
 >   >
 >
 >