Re: Bart's Coil

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Paul -
(answers to your Q's),

Tesla list wrote:

> Original poster: "Paul Nicholson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>
>
> John wrote:
> > What is the relationship between the resonant frequency of the
> > unloaded secondary coil (114.56 KHz) and the open secondary
> > (unloaded) test frequency Fo (68.493 KHz)?
>
> Malcolm wrote:
> > Would you mind re-stating the last paragraph please? I'm not sure
> > exactly what it is you're asking. Is one frequency quoted with the
> > secondary shorted end-end?
>
> Seconded.  In addition: for the o/c measurement, is the sec base
> grounded, or is the whole sec floating?

Secondary base is grounded. I removed the toroid and attached the scope
probe to the top secondary winding.
Shorted across the sparkgap and applied the signal across the primary.
Inner turn of primary is also at
ground.

>  Is the primary cap in place?

Absolutely.

>  I assume the two frequencies
>
>    Fo = 68.493 kHz (7.2 sq. -at- 2us/div)
>    Fs = 69.444 kHz (7.3 sq. -at- 2us/div)
>
> are the resonant frequencies of the primary circuit.  This sounds
> like a reasonable method providing sufficient C is added across
> the primary L so that the resulting primary Fres is well below the
> secondary Fres.  Otherwise the secondary resonance will interfere.
>
> --
> Paul Nicholson
> Manchester, UK.
> --

Is there a relationship between the self resonant frequency of the
secondary and the test frequency? I
think this is the question at hand.

--
Barton B. Anderson
http://www.classictesla-dot-com