>      This is working well, with some ocasional flaws. Sometimes I
> receive a board with burned zeners and I think this happens when the
> installer connects the circuit to a point of higher voltage, like 60VAC
> for example.
>
>      Now I'm thinking of a way to make this circuit better. I'm thinking
> of using a PolySwith in place of the fuse. Also, TVS (Transient Voltage
> Supressors) or varistors could be used in place of the zeners.

I've had good experience with a polyswitch and TVS. Polyswitches are
slower than fuses and zeners are just too weak. Another plus is that TVS's
seem to short when really overpowered, so that's good too.

Testing is less fun, no more boxes upon boxes of blown fuses :)

Cheerful regards,

Bob


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