Thread: PC Power Supply - I don't get it

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I have a pc power supply that I rigged to a switch. Plugged her in, threw the switch and the fan went on. Threw an LED on there and it went on as soon as I plugged the unit in. Ok. Got power. Now, before I start hacking this thing up, why do I need to tie all the same color lines together? Why can't I run say one red wire and one black wire to the SSC board? Or can I? I just don't get what the benefit is twisting all those same color wires together. Can anyone shed some light?

this may be of some help ATX Power Supply

You don't have to connect the same-color wires together. If you need more current then tieing 2 together will get you more current drive but if that is not needed then you don't have to.

So, according to that, it does not seem necessary to bridge all of the lines together. It seems like you can just use one and a ground. That makes more sense to me. I just did not understand the gain ofr combining all like colors.

correct - for a PC you have several connectors that require the same voltage - that is why the PC power supply has multiple wires with the same voltage - especially +12V and +5V.

The same color wires are all common in the power supply. All the yellows are common to all the other yellows, reds to reds, etc. A PC needs connections for multiple drives, motherboard connectors, video cards, etc., so power supply manufacturers provide several of each.

It pays to tie a few wires together as it increases the capacity of the wires to carry current (some PC power supplies can supply over 40 amps), also it reduces the opportunity for loose wires to cause shorts.

The back says 5v 22a and 12v 14a. Don't really care about much else. I actually wired it up and connected both the yellow and red leads from a car stereo to the yellow 12v source. Then I grounded it as well. Turn right on. Did not tie any wires together like all of the reds. Looks like I'll be using a car radio to play any cd background music.

So, I guess I can run a red lead and a black lead to any board I use that requires a 5v source. Ths rocks. I can just make leads out of the yellow wires, the red wires and the black wires and power a few things up.

By the way: just in case you were still wondering about the LED going out, it probably burned out because you didn't use a current-limiting resister. Since I'm more of a software guy that a hardware guy, somebody please correct me if I'm wrong.

I did use the resistor. The power supply does not kick on until it is actually drawing current. I tricked that with the radio. The radio always draw current in order to keep it's memory (saved stations, time, etc.). The directions show a way to do this with a resistor or 12v light bulb. I was able to do this with the radio.

I think I'm going to keep the lines separate and go with some power jacks/connectors. Should give me about 8 5v, 4 12v (5th dedicated to the radio) and 3 3.3v.