Power Supply Unit

A rectifier that converts AC (alternating current) into DC. A filter that smooths out the DC (direct current) coming from a rectifier. A transformer that controls the incoming voltage by stepping it up or down.A power supply is a device that converts one voltage to another more convenient voltage while delivering power. Power supplies are designed from the output back to the input.Despite the name, Power Supply Units (PSU) do not supply systems with power - instead they convert it. Specifically, a power supply converts the alternating high voltage current (AC) into direct current (DC), and they also regulate the DC output voltage to the fine tolerances required for modern computing components.