Actually, I've had considerable success with zero-crossing triac
dirvers/optoisolators (i.e. MOC3032??) driving a higher-power triac.
These things only cost less than $1.00 US each from Digikey and do a
great job! Easy to use and, as far as I can tell, minimal electrical
noise. Don't forget a snubber if you're going to couple it into an
inductive load! Won't be needed if all you're driving are light bulbs!!

Requiring only 10Ma for the driver LED, they're easily driven from a PIC.

For 220VAC operation, you may want to consider the MOC3042, which has a
PIV of 400V instead of the 250V for the '3032.

Good luck!
Dennis

Mike wrote:

>On 27 Nov 2003 at 12:18, Yofumo Mimoto wrote:
>
>
>
>
>>I don't know what is the best choice to manage 220V light bulbs. What i
>>want to do is to manage 3 lights and play around with this lights..
>>getting them on and off like a disco pub. Well, really i want to emulate
>>a traffic light. Then my question is what would be the best and cheap
>>way to manage the lights, with a (RELI) or opto couplers.. or what ?
>>
>>Sorry for my english !
>>
>>
>
>RELI? why doesn't that ring a bell? RELAY? They work. You'll need a transistor to
>drive the coil. 2n3904 works well for a typical 12V 30A out relay. RELAYs suck
>IMHO, but they have their uses.
>
>Opto couplers work too, but you'll need something like another Triac to handle the
>current for the lights. I'm not big on triacs. They cause EMI unless you use a zero
>crossing driver.
>
>I kinda like MOSFETs, but you'll need a pair wired as a bilateral analog switch for
>AC. The sources will have AC on them and the gate needs to be held at Vgs(on). So
>you need a constant voltage between the connected sources and gates.
>
>In that case your best bet IMHO, is a PIV PhotoVoltaic Isolator.
>
>The PVI pile is like a battery driving the MOSFET's Vgs.
>
>Check International rectifier for AN-1017a and PVI5013R.
>
>That solid state relay suggestion... I looked into those once and found them to be
>pretty expensive and for my app, non-existant in the Digikey and Mouser cats for the
>current level I required which was for block-heaters running up to 1000W.
>
>For your app, I'd bet the MOSFET PIV solution is cheaper.
>
>Don't use SCRs. They only conduct in one direction and are verbotten in lighting
>circuits in some countries.
>
>HTH,
>Mike
>
>
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