Re: How do you get the guts (or stupidity) to draw a spark
Subject: Re: How do you get the guts (or stupidity) to draw a spark
Date: Tue, 10 Jun 1997 13:07:01 -0500
From: David Huffman <huffman-at-FNAL.GOV>
To: Tesla List <tesla-at-pupman-dot-com>
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: Re: How do you get the guts (or stupidity) to draw a spark
> Date: Monday, June 09, 1997 9:26 PM
> Subject: Re: How do you get the guts (or stupidity) to draw a
> Date: Tue, 10 Jun 1997 08:06:49 +1200
> From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
> Organization: Wellington Polytechnic, NZ
> To: tesla-at-pupman-dot-com
> Hello Rod, all,
> > From: Rodney Graham Davies <Rodney.Davies-at-anu.edu.au>
> > To: Tesla List <tesla-at-pupman-dot-com>
> > Hi Shawn,
> > On Sat, 7 Jun 1997, Tesla List wrote:
> > > Subject: How do you get the guts (or stupidity) to draw a
> > > Date: Sat, 07 Jun 1997 09:35:33 -0500
> > > From: Shawn Collins <rubidium-at-worldnet.att-dot-net>
> > > To: tesla-at-pupman-dot-com
> > >
> > >
> > > I have seen many pictures on various pages of people drawing
> > > metal
> > > objects they are holding on to. At what frequency of operation
> > > safe,
> > > and how did you ever get up the guts to try it ? I know the
> > > side
> > > can kill, but according to skin effect formula (which I can't
> > > now) at 170kHz the current is only .06" deep.
> > To be safe, I'd suggest frequencies atleast 250KHz and above.
> > Anything below that and you're likely to _really_ feel the RF.
> > Anyone else tried it at < 250KHz?
> > However, I once tried an experiement holding onto a neon tube
> > coil arced to one of the wired ends, but I was only in contact
> > glass tube, not the metal bits...but I did feel the energy
> > my hands....I think the frequency, from memory, was around
> Skin effect takes place progressively as frequency increases. It is
> not a sudden thing. I have drawn arcs from a coil running <100kHz.
> principle you should be fine even at 50kHz. The jolts you can get
> mainly a result of spark gap modulation due to misfires and
> differences in firing voltages each fire. The output from a
> disruptive coil is not continuous RF so you can't expect no jolts
> all IMO. Also, you can get electrostatic effects as you move in and
> out of strike range. The worst jolts I've received have been at the
> edge of attached streamer length.
You guys in the know would never do this but I took a large stainless
steel salad bowl about 15" across in my hands and approached my small
coil to impress my audience. It impress them all right as I got a
large painful static jolt. I have drawn sparks with 1/2" copper pipe
with hardly a sensation, I will never do the bowl trick again....
BTW the coil runs at 380KHz and I had is turned down to only 6"