Power supply
What is it?
power supply: What is it ?
A power supply unit or PSU is the component that supplies power to the computer.If there is any one component that is absolutely vital to the operation of a computer, it is the power supply. Without it, a computer is just an inert box full of plastic and metal. Here is a video which give you more information.
Power Supply Basics # 1 - What is a Power Supply?