What is power supply definition?
A power supply unit (PSU) converts mains AC voltage provided from the outlet into usable low-voltage regulated DC power for the internal components of a computer. Modern personal computers universally use switched-mode power supplies. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage.
It also regulates overheating by controlling voltage, which might change automatically or manually depending on the power supply.
The power supply (PSU) is a crucial piece because, without it, the rest of the internal hardware can’t function. Motherboards, cases, and power supplies all come in different sizes called form factors. All three must be compatible to work properly together.