Power supply unit

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An ATX power supply unit with top cover removed

A power supply unit (or PSU) converts mains AC to low-voltage regulated DC power for the internal components of a computer. They also regulate the DC output voltage to the fine tolerances required for modern computing components.[1]

Modern personal computers always use switched-mode power supplies, which has both efficiency advantages and makes designing for multiple voltage inputs easier. This means that most PSUs can operate in different countries where the power input might change. In the UK, the voltage is 240V 50Hz, whereas in the USA the voltage is 120V 60Hz, and in Australia it is 230V 50Hz. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage.

Most modern desktop personal computer power supplies conform to the ATX specification, which includes form factor and voltage tolerances. While an ATX power supply is connected to the mains supply, it always provides a 5-volt standby (5VSB) power so that the standby functions on the computer and certain peripherals are powered. ATX power supplies are turned on and off by a signal from the motherboard.[2]

References[change | change source]

  1. "How to Choose Power Supply for PC: What to Know". Intel. Retrieved 2022-03-13.
  2. "ATX Motherboard". Elife PC. 2022-02-28. Retrieved 2022-03-13.