Take the 2-minute tour ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.

I am in the learning curve on LED lighting. I bought a 12v RGB LED controller that has a common anode with three color grounds that are rated to 2A on each channel. I have a number of 3W RGB LED’s with a heatsink, but no matter which resistor’s I use they cook and burn up. Even the 1W resistors cook. Granted I am testing with just 1 of the LED’s, but what am I doing wrong? Is 2A just too much for one LED? I am building a lamp with 16 of the LED’s but I should be able to test the controller with one LED? Thanks for your help.

share|improve this question
6  
How about showing us the controller's datasheet? The LEDs as well –  stevenvh Aug 8 '12 at 18:01
3  
Also, what value resistors you have tried. –  Oli Glaser Aug 8 '12 at 18:22
    
"I am building a lamp with 16 of the LED’s but I should be able to test the controller with one LED?" That is most likely a false assumption. The controller may provide excess current or voltage for one LED. Without the requested information it is simply a guessing game. –  rdivilbiss Aug 10 '12 at 16:13
add comment

closed as not a real question by The Photon, Dave Tweed, Olin Lathrop, Nick Alexeev, Kaz Dec 17 '12 at 16:43

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

1 Answer

I'm not an expert but I'm pretty confident that I can answer these questions without further information. If the controller is like mine, and gives 12 volts regardless of the load, then he's asking the resistor to drop about 9 volts (+/- 1 volt) - at 350 mA, that's 1.1 watts. In any case, no 3 watt RGB LED is going to want 2A? The 3 watt RGB LEDs I use are rated at 350 mA per colour. My advice is to use a multimeter to determine the voltage drop across the components and the current flowing through them.

share|improve this answer
    
9*0.35 = 3.15 W and what do you mean by " In any case, no 3 watt RGB LED is going to want 2A?" it's not clear. –  placeholder Oct 15 '12 at 22:50
    
A controller that "gives 12 volts regardless of the load" is just a dumb power supply. An LED controller needs to control the current, not the voltage. –  Dave Tweed Oct 16 '12 at 4:44
    
Actually a controller that gives 12V regardless of load is a regulated power supply. :-) –  akohlsmith Dec 14 '12 at 23:15
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.