What is a power supply unit (PSU)?
Q: What is a power supply unit (PSU)?
A: A power supply unit is a part of the computer that converts alternating current (AC) to direct current (DC), which is needed by other parts of the computer to function.
Q: What are the efficiency advantages of modern PSUs?
A: Most modern PSUs use switched-mode power supplies, which have efficiency advantages and make it easier to design for multiple voltage inputs.
Q: How do PSUs handle voltage inputs in different countries?
A: PSUs can operate in different countries where the power input might change, and some have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage.
Q: What is the voltage in the UK, USA, and Australia?
A: The voltage in the UK is 240V 50Hz, in the USA it is 120V 60Hz, and in Australia it is 230V 50Hz.
Q: What specification do most modern desktop PC power supplies conform to?
A: Most modern desktop PC power supplies conform to the ATX specification, which includes form factor and voltage tolerances.
Q: What is the function of the 5-volt standby power provided by an ATX power supply?
A: 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.
Q: How are ATX power supplies turned on and off?
A: ATX power supplies are turned on and off by a signal from the motherboard.
