im talking about the ones in computers. how do you hook them up to an outlet?

get a cell phone cord. and hook the wires up.

You can buy transformers, i use em, they're like 4$ u hook the wires up to the transformers, plug the transformer into the wall. You can buy em at radioshack and the like.
Cheers, Sarge

they are twelve volts

buy a computer power supply from Newegg.com - Buy Computer Parts, PC Components, Laptop Computers, Digital Cameras and more! the cheapest are like 15 bucks, then you can forget abotu wiring and hook up 5 or 6 of them at once.
then just plug in the power supply. Check out my thread entitled
Bagseed grow..first attempt to see how I did it in my stealth grow box.
I used 2 120mm case fans, each pumps 76 cfm.