A PSU, or Power Supply Unit, is a crucial component in computers and electronic devices. Its primary function is to convert electrical power from an outlet into usable power for the device. PSUs provide the necessary voltage and current to various components, ensuring they operate efficiently and safely. In addition to supplying power, a PSU also protects the device from electrical issues, such as surges and short circuits. They come in different wattages and sizes, depending on the power requirements of the system. Proper selection of a PSU is essential for optimal performance and longevity of the device.