Your PC power supply is the component that converts alternating current (AC) from your home to the direct current (DC) needed by your computer.

The power supply is located within the computer case and is visible from the rear. It's the component that houses a cooling fan and power cord receptacle.

There are usually 3 different voltages provided by a standard PC power supply:

3.3 and 5.0 volts are provided for your computer's circuitry, while 12 volts are typically provided for mechanical components such as disk drives or fans.

Warning! If you're working with a DELL motherboard, do NOT attempt to attach it to non-DELL power supply. The same goes for connecting a DELL power supply to a non-DELL motherboard. DELL has seen fit to "customize" their components, so even though the connectors appear to be standard ATX/BTX, the pinouts are different. This means that the connectors' wiring doesn't conform to the ATX/BTX standard, and if you connect a non-DELL component to a DELL component, something will likely fry (voiding any warranty).

The capacity of a power supply is measured in watts. (A watt is a measurement of power calculated as Voltage multiplied by current in amps. For example, a component running at 12 volts and drawing 2 amps is using 24 watts of power)

When you choose a power supply for a computer, it's critical that you choose one that provides an adequate amount of power for your needs. A typical household PC will usually run fine with a 450 watt power supply. However, a higher-end gaming system may require up to a 100-watt power supply. Always give yourself a little room for growth when you choose your PC power supply. You should install one that gives you at least 20-30% more power than your hardware actually requires.

Of all of the components in a computer system, the power supply is the most prone to failure. Sometimes a failure is caused by the malfunction of the fan within the component. There's no way to replace this fan if it fails--you'll need to purchase a new power supply.

Symptoms of a power supply failure may include a burning smell right before or after a failure, or abrupt shutdowns or reboots of your computer hardware.

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