Re: Tube coil capacitors

To: tesla-at-pupman-dot-com
Subject: Re: Tube coil capacitors
From: Brandywine <brandywine-at-writeme-dot-com> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Wed, 17 Feb 1999 19:58:06 -0700
Approved: twf-at-verinet-dot-com
Jeff,
   I'm sort of attempting to duplicate John Freau's work. I've got 4- 833A's
set up to be run at 5+ kvac.
   John specifies the following values for his multiple 833A circuit:
   .008 uF -at- 16 kvac mica or poly
   .005 uF -at- 20 kvac mica
   .004 uF -at- 5 kvac mica
  ( I assume all of these could be poly caps.)
   In my cap search, I've been operating under the assumption that a limited
combination of voltages and values are available in surplus or used caps. So
rather than search for specific caps, I've endeavored to simply get a feel
for what's out there. I've never shopped for caps of this type, so I have
little feel for it.
   I've considered one option: Digikey has Panasonic polypropylene caps
rated at .0056 uf, 1600 vdc. They're fairly inexpensive, so multiple units
could be purchased and series/parallel combined to produce just about any
value  needed. The ability to vary capacitance is of obvious value. Also, I
wonder if the use of polyprop units will result in a higher  circuit Q over
that which would be effected by using Mica caps?
   OTOH, a single cap of the desired value and rating requires less work,
but if that's all you've got for the particular position in the circuit,
you're stuck.
   So, you see, I'm kind of taking  a Holistic approach for now. Hopelessly
wishy-washy, but that is frequently my engineering strategy.

   I'm also looking for a 100W, 10k variable resistor or rheostat, BTW.
...Or a 5k fixed plus 5k variable -at- 100 watts, etc. ...
I've found new 50 watt rheostats for 25 clams from Digikey, but I bet there
are scads of used ones out there. It's just a matter of locating them.

   It seems that, in the past, I've run into lots of great used stuff on the
net when I wasn't looking for it. Now that I'm looking for it, I can't seem
to find as much as I accidentally ran into previously! Figures.
Thanks for your interest Jeff.
Dave H.

Tesla List wrote:

> Original Poster: "Jeff W. Parisse" <jparisse-at-teslacoil-dot-com>
>
> Dave,
>
> How high powered? What specific capacitor do you
> need? I bet you could buy it on this list if you could
> describe your needs...
>
> Jeff Parisse
>
> >Original Poster: Brandywine <brandywine-at-writeme-dot-com>
> >
> >Guys,
> >   I'm in the process of building a high power tube Tesla coil. I'm
> >looking for a source of capacitors, preferrably used, for this project.
> >Any ideas?
> >Dave Hartwick
> >
> >