A power supply unit, or PSU, is defined by its ability to take mains AC and convert it to low-voltage regulated DC power for a computer’s internal elements. Some power supplies utilize a manual selector, which provides input voltage, while others naturally and gradually become acclimated to the supply voltage. Most personal computers, on the other hand, utilize a switch-mode power supply.
Today, most personal desktop computers adhere to ATX specifications, which are comprised of voltage tolerances and form factors. The ATX power supply provides a 5 V standby voltage, which allows for the powering of the computer’s standby functions and peripherals.
In order to operate a computer’s processor and peripheral devices, the desktop computer power supply changes wavering current between a wall socket and low-voltage direct current. Direct-current voltages must be monitored with accuracy and certainty in order to allow for stable computer operation.
Computer power supplies offer the following protection: overpower, overcurrent, overvoltage, undervoltage, over temperature, and short circuit protection.
The significant differences between AT and ATX power supplies come in the form of their soft switches and connectors. In ATX-powered systems, the front-panel power switch does not switch the mains AC voltage, offering a control signal only to its power supply. Additional hardware or software can turn the system on and off because of the low-voltage control.
Power supply units that are energy-efficient waste far less heat energy and do not need much airflow to cool. This allows for an overall quieter and more pleasant operation. It is essential, however, to ensure that the capacity of a power supply matches the computer’s power needs, as the energy efficiency of a power supply experiences significant drops at low loads.