Author Options:

LED Voltage Help Answered

I recently purchased 10 led's from superbrightleds.com but I cant seem to figure out their voltage. I am not good with electrical terms (I am a noob with electronics) so the led's detail page just confuses me. If anyone could figur out the voltage of them by going to this page here it would be a lot of help. Thanks!


3.8 V @ 30 milliamps


thanks a lot! i tried to figure it out for 2 hours one day with no luck!

The maximum forward voltage, which is the maximum voltage accross the LED when it it working, is 3.8V, but it is best to run it at around 3.3V (2X 1.5V batteries will be fine)

Why not? (I'm not questioning your knowledge, I'm just interested as to why.)

Look at the graph of current against voltage. The forward volt drop is the volt drop at the operating current - so by definition, at any voltage BELOW that, you aren't getting the operating current to flow.


wait so what voltage should i run it off of 3, 3.3, or 3.8?

You HAVE to use a resistor, which depends on the supply voltage you have, to limit the current. Tell us what voltage you want to use, and I can size the resistor for you.


Steve knows more about electronics than me, so I'd follow his advice and use 3.8V, but I'd be interested to see how much difference there is between 3V and 3.8V

I'm sorry Steve, you're saying that he should operate these LEDS at the maximum specs? Best answer or not, that not right.

I don't think its a particularly bad design point for the leds chosen, yes, if they are in full outdoor ambients I'd have chosen a more conservative point, but here ?