LED voltage, how do I find it out? I have a multimeter.?

Question

It's a bright blue LED, I bought it on ebay, but don't know it's voltage or amperage.

120,3mm Water Clear 8000MCD Super Bright Blue Led,B3

Those are the ones.

Answer 1

connect it to power supply via resistor in series that is going to limit the current on about 20ma and then measure the voltage.

If you are using 12V DC adapter use 470 ohm resistor.

for 5V dc use 100 ohm.

The woltage on LED woul slightly rise with higher current.

Answer 2

The best way would be to hook up the led to a variable power supply and slowly increase the voltage from 0.0 to perhaps 3.2 VDC, while monitoring it's luminance and current draw.

From what I can find readily on the internet, it looks like 3.0-3.2 VDC and 20-30 ma forward current are the specs.

Use the voltmeter to monitor your power supply.

Best Wishes.

(Don't forget LED's are polarity sensitive!)