Describe the function of a power supply unit (PSU) in a computer.

The power supply unit (PSU) plays a crucial role in a computer by converting electrical power from an outlet into the appropriate voltage and current required by the internal components. It ensures that all parts of the computer receive stable and reliable power, which is necessary for their operation. The PSU takes the alternating current (AC) from the wall outlet and transforms it into direct current (DC) that the computer's hardware, such as the motherboard, CPU, and graphics card, can utilize.

This conversion is vital because different components operate on different power specifications, and the PSU provides multiple voltage outputs (such as 3.3V, 5V, and 12V) to cater to these varying needs. A well-functioning PSU contributes to overall system stability and performance, as inadequate power can lead to system crashes, hardware malfunction, or even damage.