how do you fibnd out what resistor you use for a led


thanks
steve

Usually for regular off the shelf 3.5V leds on 12V 470 Ohm or as close as possible to that value are used.More than that and your led is dimmer and last longer vs.less than the value brighter but less life.(dont get me wrong there are limits lol)
There are calculators just for that purpose floating around on the site if you want the exact value, but the problem is that you rarely find the exact resistor the calculator tells you
And since i rarely plug leds on the 5Vline for the reason that your vital part of the system (cpu) is using it, and i dont want to stress it more than needed i really dont know the value of the res. for 5V

http://www.projectx.com/Kits/LEDNotes/

you can use a led calculator, right here

led calculator

also, if it is only one led or many leds in SERIES, put 20 mA
normally it is 2V for red and green leds, 2.5 for blue and 3 for white, put dont trust me completely, just remember it is better to have less voltage input cause you dont want to blow up the led

Is there a dummy's guide to makeing a LED prodject? I have 0 knowledge of anything needed to do it so it would have to be fairly basic stuff.

I'm thinking about makeing a VGA cooler that fits in a PCI slot. ( useing a guide I read on here ) I then want to run LED's around the edges of it to bright that part of my case up.

I could probably buy the cooler like this for alot less but its just one of those things I want to learn by doing.