Power Supplies
A computer power supply unit (PSU) is the component which AC electrical power into DC power of various voltages used inside the PC. The PSU converts 100-120V American AC power or 220-240 European AC power into low voltage DC power. Some power supplies automatically sense and convert between European and American voltage, some have manual switches, so do not work with different power sources.

Figure 12: PSU with covering off, retrieved from http://en.wikipedia.org/wiki/Computer_power_supply



