Re: Solid State - progress.

To: Tesla List <tesla-at-poodle.pupman-dot-com>
Subject: Re: Solid State - progress.
From: Alan Sharp <100624.504-at-CompuServe.COM>
Date: 09 Jun 96 09:43:34 EDT
Greetings all,

thanks for all the info on your coil Rob:

>I'm not sure from reading the message what type of solid state system 
>you are building.

Something similar to your own.
Solid state switching PSU producing 2kV from the output transformer.
One output wire to the coil. (1500 turns on 4" PVC pipe 210kHZ) other
to earth - a resonator. (I did try driving a traditional primary and blew
a lot of FET's.  
I use a 3825 but not in current mode. A couple of buffer chips,
to drive 3 740's on each side. I'm using push pull but I'm now trying
to design a half bridge. 6" point to point of arc.

>Key is to disable the internal Source-Drain diode by putting schottkey 
>diode in series with the source.  Then a 6A 50nS rectifier is used 
>externaly from drain to schottkey diode for clamp. 

Thanks for this - I've got a reversed diode accross the FET but I'll
add this second diode in the next version - do you use snubbing as well
(I use 300ohm + 1000pf in series + second snubber with diode accross
the resistor to release when the FET is turning off.


>It has 
>about a mile of 30 gauge wire on it and resonated somewhere in 
>50-75khz range, I forget.  Puts out 150kv plus at higher current I 
>believe than ordinary Tesla coils.  Is wound on huge poly bucket.

I've bought a big bucket for the next coil - what kind of discharge
do you get from this? Quite a few people here have commented
on the benefits of high induction coils.

>I need to put together a schematic as this project is one of the few 
>that I now have without documentation.  but if there is any interest, 
>maybe I can get motivated to do this.

Please - especially for those of us in the UK where neon transformers
are hard to come by.

Alan Sharp (UK)