electronics circuit designing question?
so i am pretty good in electronics, im curently modifing a circuit and just found the value of the resistors with the ohms law. i have to lower from 12volts dc to 3.5 volts dc to a 300mA consuming high powered led with the cathode to the ground. if my calculations are right i would need to use a 30 ohm 3w resistor, should i take a 4w so the heat is not too intense? the led is not going to be light up always, its going to oscillate on music(color organ).
are my calculation right?