Nick Veys wrote:
>
> I know it should be hard, hence my difficulty! :)  Go figure!
>
> It's simply shorting two pins on a little fan controller I have made
> here, on the device it brings +5 to Ground to let it know to turn on but
> really, I don't want it to matter... I simple want something that will
> be switchable from: Open circuit -> Closed circuit -> Open circuit in
> 1/2 a second or so, nothing complex, nothing elaborate, simply like what
> a relay would do, only no real significant current (uA) or anything will
> flow though this so it doesn't need to be heavy duty at all!
>
> I'm looking at some Optoisolators and some seem like they might work,
> and I really like the idea of having 4 channels, that would simplify my
> PCB...  But again I have no experience with those and don't know if they
> would work either...


Have you considered a relay? A "real" relay that
is! :o) Simple to drive with your PIC and should
work your AC fan load ok since you say it is low
power.
-Roman

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