Re: Tesla simulators

From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Sunday, December 21, 1997 4:09 PM
To: 	Tesla List
Subject: 	Re: Tesla simulators (fwd)

Hi Scott,

> Date: Fri, 19 Dec 1997 10:57:36 -0700
> From: Scott Stephens <stephens-at-enteract-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Tesla simulators (fwd)
> At 07:18 AM 12/19/97 -0700, you wrote:
> >     One this note, does anyone have a SPICE model of a spark gap that they 
> >     could share?
> Ken Purcell was kind enough to mail me a spice model, but my ver 6.2 spice
> didn't like it. I lost his E-mail. You there Ken?
> I would model a spark gap as:
> 1) a switch with a time parameter for turn on/off
> 2) a negative resistance
> 3) something realy elaborate and near accurate, like a switch, with a
> negative resistance, with a battery (for length/threshole) and probably some
> function that relates current, to ON time, divided by gap length or cooling
> rate.
> Please post or E-mail me an accurate model if and when you get one. After I
> blow all my wimpy semi's, I'll need one.

Your best bet is to model it as a pair of back to back zener diodes 
which gets you pretty close. I have actually done this and scoped the 
waveforms. You do indeed get a linear decrement with a range of 
currents but unlike the real gap, you can also make the decrement
envelope go antilog if the currents are outside this range.