Crowbar? (was: Re: Testing Power Supplies!)

From: O. Sharp <>
Date: Mon Nov 15 20:07:04 2004

Tony Duell wrote of crowbar protection circuits thus:

> I'd rather not trust a protection device if I don't have to. Sure I like
> crowbar circuits, and they have saved my chips a few times, but I don't
> like to depend on them.

Ah, twice in one week I get to expose my wanton ignorance. :) What
typically makes up a crowbar circuit? How are they triggered? If I'm
understanding this correctly, a crowbar quickly kills the PSU and then
drains power from the system rapidly and nondestructively... but how it
accomplishes this, or knows it _should_, I don't yet understand.

O'course, one could accomplish this with an actual crowbar applied
across the PSU output... but I suspect this would not be described as
"nondestructive". :)

Received on Mon Nov 15 2004 - 20:07:04 GMT

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