The power supply unit is the piece of that converts the power provided from the outlet into usable power for the many parts inside the .
It converts the alternating current from your wall outlet into a continuous form of power called direct current that the computer components require. It also regulates overheating by controlling , which might change automatically or manually depending on the power supply.
The power supply is a crucial piece because, without it, the rest of the internal hardware can't function. , cases, and power supplies all come in different sizes called . All three must be compatible to work properly together.
, , and Ultra are the most popular PSU makers, but most are included with a computer purchase, so you only deal with manufacturers when you replace the PSU.
The power supply unit is mounted just inside the back of the case. If you follow the computer's power cable from the wall, you'll find that it attaches to the back of the power supply. It's the backside that's usually the only portion of the unit that most people will ever see.
There's also a fan opening at the back that sends air out the back of the computer case.
The side of the PSU facing outside the case has a male, three-pronged port that a power cable, connected to a power source, plugs into. There's also often a and a .
Large bundles of colored wires extend from the opposite side of the power supply unit into the computer. Connectors at the opposite ends of the wires connect to various components inside the computer to supply them with power. Some are specifically designed to plug into the motherboard while others have connectors that fit into fans, , , , and even some high-powered .
Power supply units are rated by wattage to show how much power they can provide to the computer. Since each computer part requires a certain amount of power to function properly, it's important to have a PSU that can provide the right amount. The very handy tool can help you determine how much you need.