You should lok at the MOC3030 that is an optoisolator with a triac at
the output. As long as you have the input diode 'on' you can have a
power triac fired. The nice thing about the MOC3030 is that it only
fires near 0 VAC and therfore doesn't creat noise.

Roberto Toca
tocal@avantel.net

Mark Boyce wrote:
>
> Hi all,
>
> Hope this isn't too off topic for people :-)
>
> I need to be able to switch/dim some lighting from a pic
> controlled system.
>
> The actual target lighting will be pairs of 12v halogen spots
> such as you find in most low-voltage desk lamps or alike.
>
> The circuit I'm after should produce either 0<->12v or
> 0 <-> 240v on the output and take something I can connect
> to a pic on the other side.
>
> Software is my game with a little bit of 'plug the black boxes
> together' digital electronics so I'm out of my depth here :-)
>
> Does anyone have any pointers/urls/circuits/tips/etc that might
> help ?
>
> Cheers,
>
> Mark
>
> --
> "What contemptible scoundrel stole the cork from my lunch ?"
>      - W. C. Fields