LED resistance help appreciated

[Duane Theman]

I'm trying to wire a string of led's as such:

12v - x-x-x-x-x-x-x-x-x-x-x-x - resistor - ground

But I don't know how to calculate what resistor to use, the forward voltage od each led is 3.6 with 60Ma forward current,if someone could provide me the info I'd greatly appreciate it. I've found online calcs but they show how to wire 4 sets of 3 leds, I'm seeking to put all in a row, if possible.

[firebirdude]

I'm no expert, but I believe in order to get any real life out of the LEDs, you need a constant CURRENT driver to be in line. They require exactly 60mA of current at all times.

[andru]

LEDs should last quite a long time, throw a 1a inline fuse incase of shorts and you're fine

you can also add the forward current of all the LEDs you plan to use and run them with 1 resistor rater than sevral

http://led.linear1.org/1led.wiz

[S15_Silvia]

The way you're wiring it now is such that if any one burns out, the whole string will go out. It will be like a dollar store set of Christmas lights.

V = IR should help you calculate the resistance pretty easily.

Run the LEDs in parallel, so each is connected to a common 12V bus. Forward voltage on the LEDs is 3.6V, so 12V-3.6Vdrop across the circuit is 8.4V. Currents sum up in parallel, so 12x0.06A = 0.72A. Finally, plug in to V = IR. So 8.4V/0.72A = 11.6666ohm. Look for a 12ohm resistor rated for 1A or so of current and let er rip.

Also if you really want to run 12 3.6V LEDs in series you're gonna need a lot more than a 12V source.