Don Foreman wrote:

On Thu, 20 Oct 2005 03:46:27 GMT, Ignoramus27736
wrote:



Made a 1/4" spark gap... I see sparks... Very exciting...

http://igor.chudov.com/projects/High.../Franceformer/

i


That's a neon xfmr. Three of those in series should make a dandy
Jacob's ladder! The buzzzzzzzZZZAP noise it makes adds to the fun.
With 3 or 4 of them in series, a Jacobs ladder should be able to
sustain an arc over an inch long before it goes out at the top and
starts again (ZAP) at the bottom.

The nameplate ratings can be confusing. They deliver rated voltage
under open circuit conditions, rated current at short or near-short
conditions. Once a spark/arc is initiated, voltage drops to about 1KV
in a short gap. 1KV is a near short condition for a 30KV xfmr.

A job I once had was designing electronic oil ignition xfmrs, 30KV at
30 mA. They ran at about 30KHz. In normal use the rectified AC
wasn't filtered -- but if a filter cap was added, the arc/spark was
eery quiet -- just sort of a soft hiss. A Jacob's ladder with that
was like the audio was missing.




Back in the stone age when I was doing science demos at a local science
museum, we aquired a Tesla coil that used some monster old radio tubes
rather than the spark gap system to generate the high frequency. As you
said above, it was nearly silent while making foot long sparks. The
sparks were more brush like (softer looking) than the standard spark gap
unit we had.

The really cool thing about this unit was...no leaked low frequency in
the sparks. You could stick your hand right in and not have the usual
shock you often get from Tesla's. It did leave tiny pin prick RF burns
on the surface of your skin (not deep enough to "feel").

As a demonstration piece, however, people in the audience really missed
the snapping and crackling.

Koz (who once took a solid direct hit of a 3-1/2 foot tesla spark while
well grounded and screamed "aww...FU**!" to an audience of kids as he
jerked a couple of feet. )