pkrankow Posted May 3, 2012 Share Posted May 3, 2012 the corrected image... Quote Link to comment Share on other sites More sharing options...
jsurgeson Posted May 3, 2012 Author Share Posted May 3, 2012 Hi Phil This is probably much the same as what you are doing, 2 led's (diodes) in parallel, tail to head. I have my doubts about the way you are doing it, but then I am most often wrong, not that it stops me from sprouting anyway <_< This is what I was going to suggest, based on 24vac, choose a resistor value to limit the current to about 15 - 25mA, use a diode, like a 1n4148 or 1n4007 connect cathode to anode and anode to cathode. The diode prevents reverse voltage problems. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted May 3, 2012 Share Posted May 3, 2012 If it blows an LED diode, then I will definitely go the route you suggest. I am a hack at circuit design, and admit it. I just need to get the 3A 1K resistor, and wire it into my device. BTW, the receipt I can't upload is for US$40, all from Radio Shack. Phil Quote Link to comment Share on other sites More sharing options...
jsurgeson Posted May 3, 2012 Author Share Posted May 3, 2012 I would think 1k1 1watt should suffice? Did a bit more reading, led's have a reverse breakdown voltage of about 5volts so with your 20 odd vac you might still have a problem. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted May 3, 2012 Share Posted May 3, 2012 I did some more reading based on your suggestions. Glad these components are cheap! I am going to switch to separate resistors per LED based on some reading I have done, and I will put in separate diodes for each LED. Happily this only cost little more than pocket change. Depending on the diode type or materials used in the diode, exceeding reverse voltage can ruin a LED faster than exceeding forward voltage. I get about 27VAC open voltage off my coil. Phil Quote Link to comment Share on other sites More sharing options...
jsurgeson Posted May 3, 2012 Author Share Posted May 3, 2012 Found a fairly decent schematic for running led's off mains supply, but it will give you an idea how its done, and to what length they go to protect the led's. Quote Link to comment Share on other sites More sharing options...
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