🚀 go-pugleaf

In article <1992Jul24.134854.9052@lut.ac.uk> A.J.Robinson@lut.ac.uk (Alan Robinson) writes:
>In article <1992Jul23.214214.8574@microplex.com> hsk@microplex.com (Harjeet Kalsi) writes:
>>
>>I know I've seen them in physics labs (including mine when I was in school) 
>>but forgotten what this "box" with two antennas, that has a high
>>voltage spark travelling between the antennas from bottom to top,
>>is called.
>>
>
>I think they're called Jacob's ladders, but I could be wrong.

Yes, that's what they're called.  I have one at home, made out of a neon
sign transformer and some coathanger wire.  Two wires are attached, one to
each high-voltage terminal, such that they come almost together, then rise
vertically, almost parallel but diverging slightly.  On mine, the gap is
about 1/4 inch at the bottom and 1-1/2 inch at the top (about 2 feet
tall).  The spark forms at the bottom, and the (ionized, therefore
conductive) air in the spark is heated and so rises.  The spark travels up
to the top, and beyond, at which point it ceases to conduct and a new
spark starts. It takes a bit of fiddling (run, unplug, bend wires, plug in
again, etc.) to get it right so the gap is not too wide at the top, the
spark doesn't rise to the top and stay there, etc.  You need substantial
couthangers (not the cheap thin ones) to make it work, the thin stuff has
a tendancey to start vibrating.

Lots of fun, and easy to build if you have a neon sign transformer.  But
if anyone decides to try this, FOR GOD'S SAKE, BE CAREFUL.  15 to 30 kV  
deserves a lot of respect, and due caution.  Especially in an unshielded
configuration.  If you can't be careful, don't try it at all, and don't
blame me for any accidents.


-- 
--
Charles R. Tenney	tenney@med.unc.edu   | What would the UNC school of
					     | Medicine want with my opinions?
	"My karma ran over my dogma."	     | What would I want with theirs?