DIY: Interior LED Color Change

DIGItonium

Current limiting resistors is just that - resistors. I recommend running the LED no greater than 200mA. Make sure you have a decent heat sink or something with decent surface area to dissipate some heat. If you leave it on long enough it will get pretty warm.

To get resistor value for the LED use Ohm's Law:
R = Volts / Current. Here you need to factor in the maximum supply voltage and voltage drop of the LED, and the current flow (350mA in this example).

R = (14.4 - 2.85) / 0.350 = 33 ohm. This is the minimum resistor value to use. Next you need to calculate the resistor wattage because it will generate heat as it limits the current flowing through the LED:
P = Current * Resistance = 0.350 * 33 = 11.5 Watts.

As you can see here, the resistor will dissipate almost 12W. It is very inefficient.

Quite honestly I rather run the BuckToot driver at 350mA and sacrifice the dimming feature. If you want to play it safe the most feasible starting point is with a single 100 ohm 1W resistor. That will run the LED around 100mA. It doesn't sound like much, but you won't melt things and retain dimming feature.

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