Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!purdue!decwrl!ucbvax!hplabs!hpfcso!hpfinote!maj
From: maj@hpfinote.HP.COM (Mike Jassowski)
Newsgroups: sci.electronics
Subject: Re: Anyone know about arc generators? `ffzzapp'
Message-ID: <15880006@hpfinote.HP.COM>
Date: 31 Jan 90 16:53:24 GMT
References: <5237@vax1.tcd.ie>
Organization: Hewlett Packard CICD
Lines: 48


            This is the sort of thing I mean:-
                                              o    ^   o
                                               \  ^ ^ /
                                                \^   /
						 \  /
                                                  \/
                                                ------
Anyone have any idea what I'm talking about?

----------

Sounds like you're talking about a "Jacob's Ladder".  Really pretty easy
to build if you can get your hands on a neon sign transformer (available
at most good surplus stores).  These transformers generally put out 5-15kv
at a few mA.

Connect a couple of coat hangers to the outputs, bent sort of like:



                     \                 / 
                      \               /  
                       \             /   
                        \           /  
                         \         /
                          \       /
                           \     /
                            \   /
                         ____| |____
                        |           |                           
                      to neon sign xfmr

The gap at the bottom of the 'V' shape should be pretty close (I think
that air gaps will conduct at ~10kv/cm--it should be less than this).

The long part of the 'V' should be as straight as possible.
The way this works is: the sign transformer has enough juice to 
ionize the air at the closest part of the gap.  The ionized air heats up
and rises.  The ionized air is a low resistance path, and will continue 
to conduct as the leads separate.

Air currents near the device can disturb the ionized air and cause the arc
break prematurely.

Standard Disclaimer: High Voltage can kill.  Please be careful.

--Mike Jassowski