help with leds

[Mustard Duster]

is there a formula that you can use to determine what kind of resistor you need for a certain led? thanks

 

[pik4chu]

Try your local RadioShack...youve got questions, they've got answers . Seriously though, they would know

 

[Avatar28]

No they don't. I've been to two or three rat shacks. NONE of them could answer that question for me. Try this:

http://www.bit-tech.net/article/68/

Failing that, you just take your supply voltage, subtract the amount of voltage you're going to be dropping across the diode (forward voltage), then divide by the current requirements of the LED.

That's assuming one LED. If you've got several in series, then you add the supply voltages and use the current of one of them. If you've got several in parallel, you add the currents and just use the supply voltage as if you had one.

 

[cryogen97]

check the electrical reference sticky in the general hardware forum

 

[Mustard Duster]

thanks