[TenTec] Slightly OT: Astron question, correction

[Larry Keith]

Hi...

I just replaced the one in my RS-20M with an NTE 5539.

73,

Larry
KQ4BY

Dr. Gerald N. Johnson wrote:
> 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.