[JohnWill]

I'd say around 400-450 ohms would be good for that LED if you're connecting to +12V. 400 ohms will drop 8 volts at 20 ma. If you want it a little brighter, you can go as low as 270 ohms for 30 ma across the diode.

[computerfun]

aright sweet, so now how do i wire them in the computer safely?

[JohnWill]

Well, I'd suggest heat shrink tubing for covering the resistor and it's bare soldered connections. You obviously have to make sure the 12V doesn't short to the case.

[computerfun]

ok, sounds good.

now where do i find the 12 v power supply, and can i tap into it or is there a fan outlet i could tap off of?

how do i go about actualy putting it in?

[JohnWill]

The 12V P/S is everywhere. The black and yellow leads to the disk connectors are 12V, and you can get an adapter intended for a fan to connect to one of those and solder your connections to the end of that.

[computerfun]

do i have to use an adapter?

is it going to be safe to tap into the powersupply ( its not going to raise or drop the ohm load or create a problem )

so everywire that is red or yellow is my power supply, red + yellow -

[computerfun]

could i maybe just make it really simple and tap off the fan power supply or is that 5v, and would it disturb the fans function?

im just nervous cuz i do alot of car audio and i know that in car audio anything you connect is going to effect something somewhere else, im not a computer genius like i am car audio. and i spent about 600 bucks for my sissters boy friend to build this PC for me but they broke up so i have no help on these lights.

[JohnWill]

I would not tap into the fan connection. First off, most of them are not +5, but also +12. Also, most of the fan connections have very limited current capability, and many fans are also speed controlled by varying the voltage.

If you connect the negative leg to the black connection, and the positive leg to the yellow connection of a disk drive connector, you can run all the LED's you can stuff in the case without affecting the operation of the computer. You can easily draw 3-4 amps from that connection, which is enough for several hundred of those LED's.

[computerfun]

sweet, so do i have to wire them a certain way to keep the prober impedence, or can i just wire them all in series?

[JohnWill]

If you wire multiple LED's in series, you need to consider the voltage drops of them all in selecting the resistor. I thought you said you had one?

i have one blue 3.7 - 4.5 max volt led, 20ma - 30 ma max

[computerfun]

i do have one, but now that you said i can stuff as many as i want, since there so cheap then why not

[JohnWill]

If they really drop 3.7V, you can put two in series with a resistor in the 150-200 ohm range across the +12V. What is the exact part number of the LED you have?