Re: gEDA-user: OFF: triac

[DJ Delorie <dj@xxxxxxxxxxx>]

> I am designing a reflow oven and decided to use a triac to adjust
> the power of the heater of the oven. I'm thinking of using an MCU
> (ATmega8) to control the triac. However I lack knowledge on how to
> drive a triac with an MCU. It must be opto coupled, since the MCU
> will be connected to a host computer, thus, can't flow.

Been there, done that.  http://www.delorie.com/house/furnace/

The optos were MOC3011's, the alternacs (like triacs, but can handle
inductive loads too) were digikey Q2015L6-ND's.

You'll need a pull-down pin to get enough current (10mA) or use a
transistor or mosfet to boost the current.  I think they make 5mA
opto's too, though.

http://www.delorie.com/house/furnace/board-stuffed.jpg

The white DIP-6's are the optos, the TO-220's are the alternacs.
There's a 39 ohm resistor between them that limits the onrush current
through the opto.