What is the purpose of a power supply unit (PSU)?

The purpose of a power supply unit (PSU) is fundamentally to convert electrical power from an outlet into usable power for a computer or electronic device. It takes input from an AC power source and changes it into the DC power required by the various components within the system, such as the motherboard, hard drives, and graphics cards. This conversion process ensures that all components receive the right voltage and current necessary for proper operation.

The role of the PSU is critical because without it, the internal hardware would not function, as most components are designed to operate with specific DC voltage levels. Thus, the PSU is an essential component of any computer system, providing the foundational power that enables all other hardware to operate effectively.