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Re: T.C. goals
Bill,
You are probably correct that a small VTTC is better for your planned
use. As long as all of the primary and power supply circuitry are
covered up and inaccessible, this small system is probably harmless to
you or others. Just avoid getting ozone overload, don't let any
discharges that hit your bare skin linger at any point for any length of
time, and avoid holding high-vacuum tubes (beware green phosphorescence
of the glass - it's a probable indicator of x-rays).
This is also the first time I've heard of the ion tree demonstration -
neat! The fact that you could do this without melting the individual
wires indicates that you were indeed running at relatively low power. A
low-power system is ideal for demonstrating various effects of HV RF in
a compratively safe manner. Most coilers tend to use Armstrong
oscillators with a separate "tickler" winding to provide phase-shifted
feedback and gridleak bias. You are among the few who've used a Hartley
- congratulations!
Good luck, have fun, and play safely Bill!
-- Bert --
Tesla List wrote:
>
> Original Poster: "Bill Walker" <bwalker-at-earth1-dot-net>
>
> My goal is as follows:
>
> I built a small coil 25 years ago. It used a pair of 6L6 tubes stolen from a
> PA amp. The
> secondary was hand wound with #26 wire on a 24" x 3" varnished mailing tube.
> The primary
> was wound with #12 house wire on a varnished oatmeal box. The transformer
> was
> stolen from an old TV set -- 600 volt secondary. The caps were also HV ones
> from a TV.
> The two tubes worked in parallel in a Hartley oscilator running off of raw
> AC. Tuning was
> accomplished by sliding the the primary up and down the secondary until
> maximum discharge
> was achieved: about 3 inch streamers from a needle point atop the coil. I
> believe the coil operated at about 100 KHz.
>
> With this simple TC, I fascinated my freinds and neighbors. It would light
> up small neon bulbs and flourescent lights from six feet away. I can also
> remember doing the following neat things:
>
> 1) Electron enginge. Using a piece of aluminum foil cut into a spiral shape
> and placed on my needle point with a small bead as a bearing, the streamers
> would fly off the end of the spiral generating propulsion and causing the
> thing to spin very fast.
>
> 2) Exploding match heads. A kitchen match was stuck on the needle point with
> the head in the air. The streamer would climb up the match, heating it, and
> eventually igniting it.
>
> 3) Ion tree. A piece of 30 strand litz wire was unfrayed and attached so
> that many strands of wire stuck up in the air about two inches. These would
> dance about violently as the streamers came flying off them, looked like a
> tree blowing in the wind.
>
> 3) Plasma tubes. Various electron tubes, argon bulbs, etc, would glow inside
> with sometimes wonderfully colored streamers. Yes, I held them in my hand. I
> was never concerned in those days about RF damage to skin and nerves,
> X-rays, etc. Maybe I was lucky or maybe the power of my coil was too small
> to matter.
>
> 4) My favorite experiment was simply to let the streamers crawl all over my
> fingers. Or to hold a piece of wire in my hand near the coil and watch the
> sparkes fly off of it toward the coil (actually never completing the path
> unless I got too close.)
>
> I had a blast with it. So my goal is to build another and repeat these
> demonstrations. I am
> learning that a disruptive type coil may not be ideal for this. I may go
> back to my original design
> using vacuum tubes.
>
> Bill Walker