Power supply unit (computer)

<p>A power supply unit (PSU) converts <a href="/facts/Mains_electricity/rjE90Hg0">mains AC</a> to low-voltage regulated <a href="/facts/DC_power/r9MNUx84">DC power</a> for the internal components of a desktop computer. Modern personal computers universally use <a href="/facts/Switched-mode_power_supply/YKcyRBtP">switched-mode power supplies</a>. Some <a href="/facts/Power_supply/4A8zBRHn">power supplies</a> have a manual switch for selecting input voltage, while others automatically adapt to the main voltage.
</p><p>Most modern desktop personal computer power supplies conform to the <a href="/facts/ATX/lzxcKxLF">ATX specification</a>, which includes form factor and voltage tolerances. While an ATX power supply is connected to the mains supply, it always provides a 5-<a href="/facts/Volt/KF18MXP2">volt</a> 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 <a href="/facts/Motherboard/GXB10heG">motherboard</a>. They also provide a signal to the motherboard to indicate when the DC voltages are in spec, so that the computer is able to safely power up and boot. The most recent ATX PSU standard is version 3.0 as of mid 2024.
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Power supply unit (computer) open-in-new

Power supply unit (computer)