[TenTec] Slightly OT: Astron question, correction

[Pfizenmayer]

FWIW - A much higher voltage breakdown generally indicates a higher 
resistivity substrate is used to start with and so the "ON" resistance might 
be higher than a lower breakdown device - for this application that is 
probably not an issue - you just want to trigger and blow a fuse.

73 de hank K7HP


----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at storm.weather.net>
To: <tentec at contesting.com>
Sent: Thursday, June 07, 2007 9:50 AM
Subject: Re: [TenTec] Slightly OT: Astron question, correction


> Jerry, thank you for explaining this so that I could understand.  It's a 
> big help.
> 73
> Mike
>
>
> On Thu, 2007-06-07 at 00:22 -0400, Michael Tortorella wrote:
>> Hi, last post I said the S0535W SCR was 400V, 55A....looks like the 
>> CORRECT
>> numbers are 50V, 35A.  Same question, though...would a 100V 70A (for
>> example) be OK?
>> Thanks again
>> Mike W2IY
>>
> The crowbar SCR needs only to have higher voltage rating than the power
> supply output, but 50 volts is as low as they sell. Higher voltage
> rating is no problem, just greater cost, but has no effect on the
> operation. With in reason, higher current rating is no problem other
> than the greater cost, but too much higher current rating may slow the
> turn on time of the SCR or demand a greater gate current than the gate
> circuit is designed to supply. The greater current SCR may be a physical
> fit problem because it can be larger.
> -- 
> 73, Jerry, K0CQ,
> All content copyright Dr. Gerald N. Johnson, electrical engineer
>
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