The purpose of the power supply and its function

Published: 9 June 2022

The purpose of the power supply and its function

The purpose of the power supply is to change the voltage and current from the AC mains (110 V in North America, 220-240 V in most of Europe) to the DC voltages required by the computer. The power supply typically contains a transformer, rectifier diodes, filter capacitors, and a regulator circuit. The motherboard of the computer contains a socket for the power supply unit. The PSU connects to the motherboard using a 20 or 24-pin connector. The most common ATX power supplies are rated between 300 and 500 watts.

The function of the power supply is to provide clean, regulated DC power to the computer components. The voltages required by the components vary depending on the type of component. For example, the CPU requires a voltage of +12 V, the RAM requires a voltage of +12 V, and the hard drive requires a voltage of +12 V. The power supply provides these voltages using DC-to-DC converters. The power supply also contains a fan to cool the internal components.

The most important specification of a power supply is the maximum current it can deliver. The maximum current is usually measured in amperes (A). For example, a common ATX power supply can deliver a maximum current of 18 A on the +12 V rail. The maximum current rating is important because it determines how much power the PSU can deliver to the components.

Another important specification of the power supply is the efficiency. The efficiency is a measure of how much of the AC power is converted to DC power. For example, an 80% efficient power supply will convert 80% of the AC power to DC power. The remaining 20% of the AC power is lost as heat. Power supplies are typically 70-80% efficient.

The power supply is an important component of the computer because it provides the power to all of the other components. Without a working power supply, the computer will not function. It is important to choose a power supply that can deliver enough current to meet the needs of all of the components. Additionally, it is important to choose a power supply that is efficient to minimise the amount of heat generated.

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