Re: solid state simulation

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "R.E.Burnett by way of Terry Fritz <twftesla-at-uswest-dot-net>" <R.E.Burnett-at-newcastle.ac.uk>


Hi all,

Sorry I should have elaborated slightly about using the zeners in a spark
gap model.

The back-to-back zeners only model the relatively small voltage drop of
the gap during conduction.  (A few hundered volts or so.)  For the
purposes of simulation they need to go in series with a 
"voltage-controlled-switch" device to do the actual switching function.
I found that back to back zeners provided a more accurate model of the gap
conduction than a simple positive resistance.  I'm sure it is still very
crude :-(

The zeners represent the undesirable voltage drop across the gap when it
conducts current in each direction, and represent a significant power
dissipation.  You would not want to include these in a physical
realisation of a solid state gap,  as they would waste a lot of power.

Terry is currently working on a solid state switch,  in which he is aiming
to minimise series resistance.
							Cheers,

							-Richie,

On Tue, 3 Apr 2001, Tesla list wrote:

> Original poster: "Kelly & Phillipa Williams by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <kellyw-at-ihug.co.nz>
> 
> Hi All!
> 
> While thinking about computer simulation of the primary circuit, I wondered,
> why can't you do that for real? (putting two back to back zener diodes in
> for the static spark gap was not my idea, I read it on this list ;-)
> 
> Can you replace your spark gap with a solid state device (triggered switch
> for an SRSG or a pair of back to back zener diodes for a static gap) and
> replace the transformer with a, say, 10 to 100V AC source, and then use a
> frequency probe on a DMM or ocilliscope to measure the frequency that the
> capacitor and primary coil resonate at?
> 
> This would be done to get the primary voltage down to a level an Oscope or
> (especially.) a DMM can handle. Then either of these could be used to
> measure the frequency of the primary circuit.
> 
> 10-100 VAC source charges tank capacitor. At point where SRSG fires (solid
> state switch is triggered) or static gap fires (zener diode becomes forward
> biased) the primary cap resonates with the primary coil. Frequnency counter
> measures frequency.
> 
> Question - does resonant frequency change, even slightly, with voltage?
> (15kV rms down to say, 50VAC rms)
> 
> Can this be done? Will it work?
> 
> Thank you in advance,
> 
> Alan Williams
> 
> 
> 
> 
> 
>