Re: Spark Gaps (fwd)

---------- Forwarded message ----------
Date: Wed, 22 Apr 1998 09:48:52 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Spark Gaps

Hi John,

> From:  John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
> Sent:  Friday, April 17, 1998 7:09 PM
> To:  Tesla List
> Subject:  Re: Spark Gaps

> >Not exactly sure what you mean. You can turn a transistor off any 
> >time you like. I tried turning off at first primary energy notch,
> >first primary quarter cycle (thank heavens for parasitic zeners in 
> >the FETs), etc. It behaved just like a gap except it was a gap I 
> >could effect ideal quench/dwell times with. The test setup was a 
> >standard disruptive two coil system with k set to about 0.1
> >
> >Malcolm
> >
> -----------------------------------------------------
>   Malcolm -
>   I meant that because Tesla coils use dampened sine waves the quenching
> would be different compared to quenching pulsed waves such as square waves.
> Pulsed waves can have long off times where quenching would have no significance.
>   John Couture

Just think of the transistors as a gap you can turn on and off any 
time you like. The fact that waves are damped has no bearing on the 
gap whatsoever. It reflects the fact that the coil operates on a 
limited energy store. There was absolutely no difference between the 
transistor setup and a standard disruptive setup save that the 
primary ringdown was exponential due to the lack of the negative 
resistance characteristic attributable to the airgap.