I'm replacing the LED in a car tail-light. Naturally, it will run off 12V (battery) but the circuit I have uses just an LED and a 0.6w (440ohm) resistor. But the existing circuit includes two, larger resistors (the power ratings, that is, I assume are higher) and a diode. Can anyone tell me what functions these play in the circuit?
Is the diode for protecting from reverse current, as I'd assume? (not for voltage drop or anything like that), if so, why would there be a risk of this?
And why are the resistors so much larger, when the LED I put in should easily run from a 0.6 resistor? Would the existing LED be a higher wattage LED; It's just the same looking led, there's no heat-sink or anything.