[Amps] 3-500Z glitch resistor

[Roger (K8RI)]

TexasRF at aol.com wrote:
> I don't recall seeing any info about hv crowbar circuits. Sounds  interesting 
> though. Where is the info?
>   
Originally the "crowbar" was just that.  A piece of metal that shorted 
the HV to ground if any one opened the cabinet with the power on. 
Opening the cabinet closed a mechanical switch (usually something like 
a  knife switch) to ground from the HV.  The tended to be noisy, but 
very effective.  You usually didn't forget more than once...or twice. 
<:-))  Since then crowbars have become more sophisticated although the 
original use still prevails.  However, the SCR, or what ever is used 
should be robust enough that it does not fail with use.

The surge protecting resistor is still a surge protecting resistor in 
"series" with the HV while the crowbar circuit is in parallel (to ground).

73

Roger (K8RI)