Led Resistor

im lookin at some leds and junk and im curious...whats a resistor do?

a resistor adds resistance. Since LEDs use such little power they require resistors (unless u wire 4 or more in series.) if you use an LED without a resistor a few things could happen: You could kill your battery, you could cause a short, or you could ruin your LED. Most LEDs will work with a max of 4.5 volts. Your car is 12 volts. Hence a resistor is required.

hrm..cool..i learned somethin today

So if you use 4 LEDs in series you do not need a resistor? What if you wire 8 LEDs in series, will the light be dimmer? I was thiking of running 2 red LEDs in each AC vent. So if I wire 8 LEDs (4 vents) in series all hooked to a switch it should work?

Check out the diagrams section of the forum, VERY helpful.

Yeah I saw the diagrams so I know I dont need a resistor, but will it make the light any weaker by wiring 8 in series?

Basically if you wire 4 LEDs in series and also wire 8 LEDs in series, which one will be brighter? Or will they be the same?

I doubt it will be very noticeable. LEDs use such small amounts of power i don't think it would have a very drastic effect.

wouldnt that make em half as bright tho?

Well...i'm not sure what the resistance is for one LED (it varies with color) and i use 370 ohm resistors (with one blue LED.) Since i don't know the resistance of one LED i can't say exactly how much added resistance there is, but like i said before i doubt it is enough to make a difference. i went from a 220 ohm resistor to a 370 (just switched resistors, same LED) and saw NO difference in brightness. So, all i can say is try it.