Power Supplies

The power supply (PSU) converts high voltage electricity from the mains power supply (usually 110-240v AC), into regulated low-voltage DC power for the internal components of a computer.

Power Supply Unit

There have been many different types of power supply in the past, however the computer industry eventually settled on using the ATX power supply.
ATX stands for Advanced Technology eXtended and is a motherboard and power supply configuration specification developed by Intel in 1995.

Read page 73 – 75 of the textbook “Exploring Computer Hardware”.