Power Supplies

A power supply is the energy center for any computer system, without it the computer would not have the ability to turn on. A power supply differs from a battery in that it draws energy from a wall outlet. Batteries perform a series of chemical reactions between acid and alkaline which limit their lifespan, while wall outlets provide virtually an unlimited source of power. This unlimited source allows your PC power supply the opportunity to provide energy for your computer on a twenty-four hour basis. The PC power supply provides energy for all components in the computer including, the hard drive, CD-ROM drive, keyboard, mouse, motherboard, memory, and USB port.

The PC power supply is easily recognizable in any computer system because it connects directly to the motherboard and hard drives. The power supply is approximately 100 millimeters deep by 113 millimeters wide by 63.3 millimeters tall and is encased in a shiny aluminum shell. There are anywhere from six to twelve different ribbons of cable protruding from the body of the power supply. The plug which connects your wall outlet to the computer connects directly into the rear of the power supply. This fact also makes the power supply an easily identifiable component.

There are three functioning parts to any PC power supply: the peripheral ribbon, the power switch, and the voltage switch. A discussion of these parts is located below.

Peripheral Ribbon - The ribbon protruding from the power supply casing usually consist of four strands of wire which are yellow, black, black, and red. The black wires are ground points, while the yellow wire supplies twelve volts, and the red wire supplies five volts. Both of these voltages are necessary to power any drive in the computer. The red five volt wire supplies all the digital components with power, while the yellow twelve volt wire supplies all the mechanical components with power. The wires are easily connected to the drives because they...