Resistor for P4

[darthdan]

I may be getting stupider. I seem to be asking newb questions lately. In keeping with that pattern... Using 4.5v battery pack, P4 forward voltage is 3.7, at 1 amp, would I use a 1ohm 2 watt resistor?

Also in things I should know by now... Does the MR sound board limit current at all? Or just allow the led to suck whatever it wants to suck up? I don't have any testing equipment, and was wondering what the current draw would be if I hooked up one of these P4's to a MR sound board at 4.5V.

[Jedi Ranger]

According to the LED Pro program, a 1ohm resistor will work, but the LED will only get 800ma. A 0.8ohm resister would allow a full 1000ma through, but those aren't available at TCSS store.