jensenracing77

i love electronics but i need help with this one. it is dealing with LEDs, i need to figure out what resistor i need. i have
8 volts to supply the LED
the LED operates on 4 volts and requires .02 amps
how do i figure out what resistor i need?

i have googled LEDs but it keeps coming up with flashlights, i need to look longer maybe.

66ninetyeightls

Just do a search for LED Resistor Calculator. There are a number of them on the net.

jensenracing77

lol, thanks. that was easy. i looked for several differant things but not that.

66ninetyeightls

Very welcome.

Lady72nRob71

So you have to drop the other 4V across the LED. Since current is known and will be constant across the resistor also, apply Ohm's law - R=V/I
4/0.02=200 Ohm.
Now what wattage? P=E2/R or I*V.
0.02*4=0.08W.