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Re: Micro coil specs? pics? (was Micro coil earthing)

Original poster: "Jason Petrou by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jasonp-at-btinternet-dot-com>

Joe, I built a micro mini ultra tiny microscopic coil (as described by my
physics teacher). It was 6W off an ignition coil, 950V (yes not 9.5KV) at
like 10mA. It was wound over a 4" 0.8" powder vitamin tube. I used some
hornby railway trach for the primary and a little wheel of a train to tune

I notices you wanted an idea for a small SG - well heres what I used:

I bought a micrometer and glued two insulating pads onto each point, then
put little tungsten blobs (best word ;) on the end, which were connected to
the leads. Because of the very low voltage there was no arcing problems, and
I could adjust the sg on the fly, as it were. To quench I used an Argon gas
bottle. I used 3 HV caps in paralell from RS components as my cap bank and I
used thick solid core mains wire for my leads. The SG arced over at about
1/16 of an inch and usng a microphone and a scope (crude i know) i checked
tthat It was not misfiring (which it wasnt). I can touch the topload (a
little ballbearing) and i get a little tingle. The sparks are about 1" long
and there is a very bright corona on the topload when there is no availible
ground wire.

Some cool experiments that you can do are to put various lightbulbs on top
of the topload and hold them - you get plasma forming inside them. Also
spraying welding argon over the topload creates a whitish yellow glow.

Have fun,
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, May 03, 2001 6:31 PM
Subject: Micro coil specs? pics? (was Micro coil earthing)

> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> Gary, all..
>   I couldn't help it...I had to try and build my own minimicroscopic coil
> last night.  22.5W input power, and only 1" arcs to ground....needs some
> fine tuning and better gap quenching...better coupling, a top load, better
> ground rigid construction, properly terminated wires, a new primary...this
> is starting to sound like Ecto-1 before it was all fixed up!
>   Lesse...the specs:
> power supply is a 4500V 5ma single coil neon ramped up to 5250V on a 140V
> variac.  I'm using the ground lead as the second HV lead in the circuit.
> secondary is just over 700 turns (5.5") of 33-gauge wire on a .6"
> 6" high glass test tube
> the primary is two turns of 12-gauge household wire w/insulation and
> close-wound on a section of 1.5" PVC pipe
> spark gap is 4 copper pipe sections laid out on a glass tabletop, adjusted
> manually.  One end pipe has a lead from the cap string touching it, the
> other end pipe has the end of the primary coils wire touching it (very
> secure ;)
> cap string of 17 Panasonic Terry caps in series for 3.3nf (recalculating
> a 2-turn primary gives me a needed cap value of 15.6nf....oops!)
> The leads are across the HV terminal from the NST and the ground lead from
> the NST.  Also, the end leads touch the spark gap and the other end of the
> primary
> RF ground is a small 6" toroid on the glass table top that sits on top of
> the extra wire from the bottom of the secondary
> the secondary is stood up in the middle of the primary, the extra wire off
> the top is held with pliers (calculations used it as a 2" sphere)
> maybe with a fan across the spark gap or a whole new gap (I'm in desperate
> need for a small-but-GOOD static gap or very minute rotary), 2 strings of
> caps in series-parallel for 16nf, a real 2" sphere top load, a better
> (foil everywhere!) and I'll get to see some better sparks!  Are there any
> actual photos out there of tiny coils working well?  I'll post results of
> the reworkings as soon as they're done.
> -Joe
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, May 02, 2001 5:48 PM
> To: tesla-at-pupman-dot-com
> Subject: RE: Micro coil earthing
> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <Gary.Lau-at-compaq-dot-com>
> >Matt im 16 and built 2TCs a normal 360W one and a really tiny mini
> >microscopically small 6W one. got any pics of your one?
> >
> >Jason
> 6 Watts?  Could you share a few more details?  What was the power supply
> and what were the spark-results?
> Gary Lau