On Tue, 13 Jan 2009 07:23:21 +1000, "David Duffy" said: > Hi guys, > I have a small board that I'd like to drive a 5V reed relay straight > from a port pin of a small PIC. (cost and size is an issue) The coil is > 500 Ohms so only draws10mA @5V. Are there any gotcha's with doing this? > I was going to use a 1N914 as the back EMF diode. Hi David, There's no reason not to drive the relay directly. I'll save you a part, too. I see no need for the diode if you are driving from a normal output, since the output is driven in both directions it will clamp even better than a diode. Only if you were shutting off the relay by switching the pin to input state would it be needed. Cheerful regards, Bob -- http://www.fastmail.fm - One of many happy users: http://www.fastmail.fm/docs/quotes.html -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist