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LEDs - Under-volt, over-amped? Answered

My issue: Have multiple LED drivers, (high power LED instructable) and connected the wrong one. The LEDs are not dead.

My LEDs are rated at 9-12v, 950mA and I have sets of 4 in series hooked up to a 36v power supply. The driver I used has a .3ohm resistor on it. so it's putting out ~1.3A The LEDs should have burned up.

Since the driver eats up a little of the voltage, each LED is getting ~8.75v. Is this why they haven't burned up?




2 years ago

If you've undervolted them, how can they burn from over current? I don't think that can happen (Though I am a bit confused about this subject too...)


Reply 2 years ago

Yonatan is actually correct.

Four LEDs in series ( assume the most damaging situation ) all LEDs are 9V x 4 = 36 volts as a minimum.

That means the series LEDs will barely light ie come_on.

If Stip could let us know if the values the ~1.3A string and 8.75V per LED a measurement or estimate ? Before or after you connected the wrong what ??

The destructive component of electricity is current flow a result of the pressing voltage and a little voltage change in a diode which causes a large current flow change when compared to a linear resistor as depicted in the picture.

Res- LED-FWDvolt.gif

2 years ago

I"m clearly missing a fundamental of electronics/LEDs here. :)