ASR33 selector magnet driver card

[dwight elvey]

>From: Mr Ian Primus <ian_primus at yahoo.com>
---snip---
>
>So - in replacing this component, what should I be
>looking for? The only specification givin is 100A, but
>I see varistors in various places rated in terms of
>Joules or Volts. I don't want to replace the varistor,
>only to have it not give me any protection for that
>transistor.
>
>Thanks!
>
>-Ian

Hi
One could also use a pair of power zeners. Wired back to back, they
make a fare protector. Actually, in your case, a single zener might be
better. It would clamp the voltage in one direction to the normal
operating level while allowing only a diode drop the other direction.
Dwight

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