POWER SUPPLY

Power Supply

A power supply unit (PSU) converts main AC to low-voltage regulated DC power for the internal components of a computer.Some power supplies have a manual selector for input voltage, while others automatically adapt to the supply voltage.

Most modern desktop personal computer power supplies conform to the ATX Specificationa, which includes form factor and voltage tolerances. While an ATX power supply is connected to the mains supply, it always provides a 5V standby (5VSB) voltage so that the standby functions on the computer and certain peripherals are powered. ATX power supplies are turned on and off by a signal from the motherboard.

Functions

The desktop computer power supply changes alternating curent from a wall socket to low-voltage direct current to operate the processor and peripheral devices. Several direct-current voltages are required, and they must be regulated with some accuracy to provide stable operation of the computer. A power supply rail or voltage rail refers to a single voltage provided by a power supply unit (PSU).