Re: GE Solid State Thyratron

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

Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net> 

Hi David,

Solid state thyratrons are simply SCR's packaged as plug-in replacements 
for vacuum tube varieties. Common ones I've seen are designed to replace 
4C35's but there may be others. There are similar devices to replace some 
types of ignitrons as well.

Thyratrons are designed to discharge unipolar pulse forming networks, and 
unless specially designed for the task, they cannot handle much reverse 
current. Because most thyratrons can only safely pass current only in one 
direction, you'll need to either need to insure that the thyratron quenches 
early (the first positive half cycle, and long before before 
Primary-Secondary ringup has completed) or you'll need to use the 
equivalent of a freewheeling diode across the thyratron to carry the 
reverse current. An unprotected thyratron that arcs back under reverse 
voltage conditions can be easily damaged or destroyed. BTW, there are also 
H2 diodes that are designed for just this task, but they are scarce.

Because of the reduced operating pressure (fewer conducting carriers), 
thyratrons are even lossier than spark gaps. For certain pulsed power 
applications they more accurate/repeatable triggering, better quenching, 
higher rep rates, and lower maintenance than spark gaps. Unfortunately, 
Tesla coils are not one of the applications that benefits from thyratrons.

Best regards,

-- Bert --
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Tesla list wrote:

>Original poster: "David Trimmell" <humanb-at-chaoticuniverse-dot-com>
>Hi, what is a solid state Thyratron? And what is the difficulty of using
>H2 Thyratron's, I am aware of Richard Hull's venture, but have the
>driver circuits become easier for the layman (improved IC's, etc.)?
>Regards,
>David Trimmell
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Friday, February 27, 2004 3:05 PM
>To: tesla-at-pupman-dot-com
>Subject: GE Solid State Thyratron
>Original poster: Zimtesla-at-aol-dot-com
>Hello List Members,
>A friend of mine has a couple GE solid state thyratrons model 4JS1. I
>was
>looking for some specs on the thyratrons.  Wondering if anyone has a
>link?
>Also wondering if these thyratrons would be suitable for driving a
>primary
>circuit?
>Thanks
>Jim
>.