On Sat, 10 Feb 2001 13:52:39 -0600 Bob <op1cwk@FLASHMAIL.COM> writes:
> However, instead of futzing around with resistors, or a zener setup
> like Roman
> mentioned, I was thinking that I could use some sort of Opto
> circuit/chip to
> relay the zero crossing event to B0 instead.  This would probably
> give me a
> better chance of getting it UL/CSA approved if/when I decide to do
> that (5000V+
> isolation trumps most anything).  I'm sure that any type of direct
> connection
> setup would probably scare the PooPoo out of UL & CSA too ;-).  Any
> ideas on how
> to do it that way?  What part(s) to use?  Anyone?
>
> Thanks again for everyone's input on this.
>

        Since the power supply is non-isolated, it doesn't seem that an opto
gains you anything. The whole PIC circuit is going to be at line
potential. There is nothing wrong with this as long as you meet clearance
and creepage distances. So, I don't think UL or CSA would have a problem
with it, but I think it's a lot easier with a transformer (then you'd
need the opto, such as an MOC3023 to get back up to the triac).

Harold

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