It takes the mains supply and converts it to various lower voltages, suitable for the electronics in the computer. Usually 5v 12v 3v
A computer power supply takes the AC power coming from a wall socket, and then converts it into lower-voltage DC to power all the components inside. Almost every component of a computer will connect directly to the power supply, with the exception of smaller parts such as fans, which can pull power through the motherboard.
The answer is the power supply unit or PSU.
The power supply is usually always located at the top of the computer tower, to the back. Whats easy to find is whatever your power cord from the wall plugs into on the back of your computer, is your power supply box. From there, the power is reduced and sent throughout the computers hardware. (You'll also see that its the box with all the wires are coming out of, inside the computer)
The PSU, Power Supply Unit
Sometimes when people buy a computer power supply unit (PSU), there are several components in the box: a AC power cable to connect the power supply to the wall mains outlet, the power supply itself (PSU) that converts mains power into more useful forms of power, and one or more DC power cables that connect the power supply to the motherboard and other parts of the computer. (On a modular power supply unit, those cables can be detached from the PSU). A computer power supply is in a metal box that is difficult to open, so most people treat a computer power supply (PSU) as a single indivisible component. Inside a computer power supply is a transformer to help convert mains power into more useful forms of power, power diodes and power transistors typically mounted to a heat sink, and other components to help the conversion or to filter the power to meet EMC requirements, and often a fan to blow air on the heat sink to keep the transistors from overheating.
Power Supply Unit.
The function of the power supply is to convert wall current to the correct current for the computer and distribute power to all the internal computer components.
A PSU in a system unit is the power supply unit. It provides well-regulated power for the computer and its peripherals.
A computer's (PC's) power supply is a sealed unit and should be replaced as a whole - It is dangerous to try and repair the inside of that sealed unit (that is why it is sealed).
Sometimes when people buy a computer power supply unit (PSU), there are several components in the box: a AC power cable to connect the power supply to the wall mains outlet, the power supply itself (PSU) that converts mains power into more useful forms of power, and one or more DC power cables that connect the power supply to the motherboard and other parts of the computer. (On a modular power supply unit, those cables can be detached from the PSU). A computer power supply is in a metal box that is difficult to open, so most people treat a computer power supply (PSU) as a single indivisible component. Inside a computer power supply is a transformer to help convert mains power into more useful forms of power, power diodes and power transistors typically mounted to a heat sink, and other components to help the conversion or to filter the power to meet EMC requirements, and often a fan to blow air on the heat sink to keep the transistors from overheating.
The power supply makes the computer run, without any type of power supply it would be impossible to run a computer. The mains power supply for a laptop and the power supply unit of a desk top, both convert the high AC voltage from the mains power and convert it to low voltage DC, for the electronics of a computer to use.