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Re: tube advice needed



Subject: Re: tube advice needed
  Date:  Thu, 22 May 1997 13:23:11 -0400 (EDT)
  From:  FutureT-at-aol-dot-com
    To:  tesla-at-pupman-dot-com


<< John, I am the guy that has a CX140 thyratron.
> What you mentioned about using a thyratron as a "switch" or spark-gap,
> is what I would like to do. I am a little weak on the theoretical
> aspect, however, and so need some help. Is there any information that
> you know of, that goes into using a tube in this matter? Has anyone out
> there done it?
 
> Gene Lambert
  >>

Gene,

I have not tried the thyratron idea yet.  A normal (non-hydrogen)
thyratron has a rather slow de-ionization time that is longer than
one RF ac half cycle long.  Thus, these thryratrons will not shut off 
until the circuit has rung down -- so they're not good quenchers.  In
addition, thyratrons are not designed for ac use, the reverse voltage
will tend to cause damage within the tubes.  To solve this, two "back
to back" thyratrons can be used, each conducting during one half 
cycle.  May be tricky to trigger them properly -- I have no experience 
in this area.

A hydrogen thyratron is a different beast -- it can deionize in less
than
one RF ac half cycle and therefore can be used as a quencher (TC's 
work best with fast, first beat-notch, quenching).  But again, these
should be used in back to back fashion to work properly.

Richard Hull has done some preliminary work with hydrogen 
thyratrons which he has posted on this list in the past, and some 
of my comments above are based on his work.  Perhaps Richard 
will present his thoughts on the matter.  I seem to remember reading
that others have also done some thyratron experiments, but don't 
remember the details.

Wish I could be of more help,

John Freau