RE: Spheres vs Toriods

On Mon, 8 Apr 1996 13:00:07 +0700 you wrote:

>I must add here, that while spheres are a 'bad' terminal capacitance to
>use under most conditions, one interesting phenomena I noticed using a
>nice shiny sphere was the 'single tenticle effect'. Something that doesnt
>occur on torroids to the same extent. One long streamer (discharging into 
>air) 'swinging' in a random fasion all over the place.....walk up cautiously
>and outside strike distance of course, and sometimes you can coax the streamer
>to swing round and 'look you in the eye' so to speak.....quite entertaining!
>If you have never tried it before, its worth a go just for the effect! Keep
>those torroids for the big sparks though!! Another use I found with spheres
>is isotropic loading configurations to create a minimal capacitance 'needle'
>discharger. Though fairly inefficient these are great for powering up spinners.
>........At the end of the day torroids win of course!!!!!

Last year when I was listening to RQ talk about increasing terminal
capacitance I began to stack things on top of the toroid.  I took a
clip light shade (Al) and set it on the toroid.  Then I placed a 4
inch diameter solid aluminum sphere that I happen to have and set that
on top of the shade.  I was trying to increase the surface area to see
for my self how it would affect the tuning, freq., etc.  Well it
showed me what RQ was saying.  The arc, though, was alternating
between the sphere on top and the sides of the toroid.  This was a
small coil.  The toroid is only about 7 inches across.  I tryed a few
other things and messed around for a while.  It seemed to me that the
tendency was for the spark to break out from the sphere more than the
toroid.  I didn't pursue it at the time, but I have though about it
off and on since then.  If you stacked a sphere on the toroid that was
larger in surface area than the toroid, would the spark only come out
the top?  What if it was half a toroid on the bottom and half a sphere
on top?  What about half a sphere with a radiused edge?  It seems
these shapes would combine the best of both the sphere and the toriod,
except for easy of construction, I guess.  Unfortunately, I have not
had the time and facilities recently to try any of this.  If I do I
will let you know.


Mark R. Napier