Re: Lumped vs. Helical Resonator

To: tesla-at-pupman-dot-com
Subject: Re: Lumped vs. Helical Resonator
From: Jim Fosse <jim.fosse-at-bdt-dot-com>
Date: Fri, 24 May 1996 06:23:12 GMT

>>From hullr-at-whitlock-dot-comThu May 23 21:15:53 1996
>Date: Thu, 23 May 1996 11:45:46 -0700
>From: Richard Hull <hullr-at-whitlock-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Lumped vs. Helical Resonator
>
Richard,
>I don't know the ansewer to all your questions.  I would imagine the turn 
>to turn C would not go away on the coil, even in a guarded arrangement, 
>only the isotropic C would disappear.  A new capacitance due to the guard 
>itself might develop, too.  Only an experiment would tell.
>
If the secondary were already "potted" in polyurethane I would expect
to see only a small increase in the turn to turn C. If the secondary
was not potted, I would expect the turn to turn C to increase due to
the higher permitivity of transformer oil (over air).

I expect the isotropic C would increase. "WE" moved the "ground" from
say 3' away to say 1' away and filled the space with a higher
dielectric constant material.

p.s. oops, I just reread the thread. I answered above on the helical
resonator in an oil can, not the thought experiment;(

My thought experiment was a try at getting a feel for how the toroid
interacts with the secondary.

>Voltage at RF frequencies on the order of what comes from a big TC would 
>not be a matter of mere resistive drops.  A capacitive divider might be a 
>better choice for a TC coil voltage measurement device.
>
I keep smoking my home rolled caps at 15kV, I think I'll pass building
this one with standard construction methods;) However, by going to an
air insulated plate, outside the strike range, one could build an
E-field meter: better known as a field mill. From there it is a simple
matter of calculating the voltage. I plan to build one as soon as I
get my "small" TC back on line.

	Highest Regards,

	jim