fat-tony

I'm trying to control a resistive 120V (2 lightbulbs actually) using a microcontroller. Outputting hi/low signals is no problem, but how do I actually switch the load? I'm assuming (based on what I've seen here and elsewhere) that a triac is the right way to do this, but.... I don't understand how they are actually implemented.

Any suggestions?

k7elp60

Yes that is the way to do it. Use a opto coupler like the MOC3031 to control the triac. The logic level from the computer will drive the triac.
:lol:

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Eclipsed

I'm assuming you mean 120v AC right?

http://www.americanmicrosemi.com/tutorials/triac.htm
http://www.aaroncake.net/circuits/dimmer.htm
http://www.tpub.com/neets/book7/26e.htm

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fat-tony

That's making some sense


I especially like the opto-isolator first, since I don't really want to have a way for the mains voltage to hit my micro.

ambrose

see www.microchip.com

type lamp dimmer in the search

a complete microcontroller schematic is there using a triac.i think it will be of some help for u.

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Nilo

Hey hey, why to be so complicated?
Triacs are mostly recommended if you want to trigger the load in high speed, like shaping the 60Hz wave form(dimmer do this) or switching something quickly.
If you just want to switch a load with slow rate (less than 1 time per second), use a relay.
Just choose one that will support the load currect. If your load is a regular 100W 120VAC lamp, the current will be only 0.8A and most micro relays support it.
if your triggering ciscuit doesn't have enough currect to direct connect to the relay coil, use some current driver as attached.

Nilo

Attached Images

Imput_118.jpg (12.2 KB, 928 views)

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