I have been wiring up some 350mA RGB (3W) lights to go behind a friends bar, but the resistors are hot! Too hot I think. I measured the resistors at 110C each with all three colours turned on.
The Leds are power by a 13.80V 20amp power supply, I have been using 33 Ohm 4 or 5 watt resistors (not sure on the wattage)
Red 2.20v @ 350mA 33 Ohm
Green 3.55v @ 350mA 33 Ohm
Blue 3.55v @ 350mA 33 Ohm
now if the calculations are correct the resistors are dissipating 3450mW if I use a ten watt or 15 watt resistor will it be cooler? I think the best solution would be to reduce the input voltage to 5v or 9v, or use individual 1-2Amp mains adapters per Light also thought about using a old pc PSU.
Would like your thoughts ideas please.
Don
The Leds are power by a 13.80V 20amp power supply, I have been using 33 Ohm 4 or 5 watt resistors (not sure on the wattage)
Red 2.20v @ 350mA 33 Ohm
Green 3.55v @ 350mA 33 Ohm
Blue 3.55v @ 350mA 33 Ohm
now if the calculations are correct the resistors are dissipating 3450mW if I use a ten watt or 15 watt resistor will it be cooler? I think the best solution would be to reduce the input voltage to 5v or 9v, or use individual 1-2Amp mains adapters per Light also thought about using a old pc PSU.
Would like your thoughts ideas please.
Don