Re: Q - Driving HV DC pulses? (fwd)

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Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Thu, 06 Oct 2005 20:58:34 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Q - Driving HV DC pulses? (fwd)


>
>Good info. Using tubes are not by any means a the best choice for this
>application. Solid-state solutions are ideal. Tubes may, however, become
>necessary to switch the high voltages quickly. BTW, it seems like the triac
>is a close solid-state relative to the triode.


FET -> triode
SCR -> Thyratron or Ignitron
Triac -> back to back SCRs or Thyratrons

If you need fast (microsecond), don't even bother with SCRs and Triacs... 
Think FETs

Surplus.. for HV, a triode or, maybe, a pentode or tetrode will be the easiest.
A single device, and multi kV tubes are readily available 
cheap.  Microsecond switching is easy to come by.  You'll need a grid drive 
that can swing, perhaps, a couple hundred volts, which you can get easily 
with almost any decent power FET, which in turn can be driven by a standard 
pulse generator.


Or, a pair of thyratrons.  One as a  series switch to turn ON with a shunt 
tailbiter to turn the pulse off.

>Regards,
>
>Jeff