Re: SCR's

• To: tesla-at-poodle.pupman-dot-com
• Subject: Re: SCR's
• From: Tesla List <tesla-at-stic-dot-net>
• Date: Fri, 14 Mar 1997 08:51:45 -0600
• Approved: tesla-at-stic-dot-net

Subject: 
        Re: [Fwd: Re: SCR's]
  Date: 
        14 Mar 97 02:53:38 EST
  From: 
        Alan Sharp <100624.504-at-compuserve-dot-com>
    To: 
        "INTERNET:tesla-at-pupman-dot-com" <tesla-at-pupman-dot-com>


> I don't have any SCR reference material handy, but I seem to recall that even 
> farily small SCRs can handle several thousand amps (peak), and that the large 
> ones peak over 10,000 amps - If my memory is correct, they should be ideal to 
> simulate a spark gap.
> 
> However, at low voltages, you're really limiting the peak amperage.  I don't
> know what the on-resistance of a SCR is, but let's assume 10 ohms.

I'm not sure that SCR's can switch fast enough. I tried using MOSFET's
to
switch large currents into a primary (no capacitor - instead I drove the
switch at the resonance frequency. I got a 2" spark and I killed 4 or 5
FET's - the problem was that as the voltage rose in the secondary -
it was fed back to the primary. Result overvoltage killing the FET's.

FET's have very low on resistances, 0.1 ohm, switch very fast
ie 50nS and handle high peak currents (40A), and they can be switched
off. Unfourtunately you would need a lot of them to handle 1000A at
10kV - back to the spark gap lads.

Have fun,

Alan Sharp (UK)

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