Computer power supply

A computer power supply is built with a power supply unit (PSU) which is the component that supplies power to a computer. More specifically, a computer power supply is typically designed to convert 100-120 V (North America and Japan) or 220-240 V (Europe, South America, Africa, Asia and Australia) AC power from the mains to usable low-voltage DC power for the internal components of the computer, usually 12 volts and 5 volts dc pins. Some power supplies have a switch to change between 230 V and 115 V and some high efficiency computer power supply models have automatic sensors that switch input voltage automatically, or are able to accept any voltage between those limits.

Computer power supply specs

Computer power supplies are rated based on their maximum output power. Typical power ranges are from 300 W to 500 W . Power supplies used by gamimg solutions sometimes range from 500 W to 1300 W. A common way to reach the power figure for PC PSUs is by adding the power available on each rail, which will not give a true power figure. This means that you cannot use the PSU maximum rating on one rail, but only as a total. Therefore you can overload a PSU on one rail without having to use the maximum rated power.

Computer power supply pins

1. PC Main power connector: Is the connector that goes to the motherboard to provide it with power. The connector has 20 or 24 pins. In cases where the motherboard has a 24-pin connector, some power supplies come with two connectors (one with 20-pin and other with 4-pin) which can be used together to form the 24-pin connector.
2. ATX12V 4-pin power connector. A second connector that goes to the motherboard (in addition to the main 24-pin connector) to supply dedicated power for the processor. For high-end motherboards and processors, more power is required, therefore EPS12V has an 8 pin connector.
3. 4-pin Peripheral power connectors (Molex): These are the other, smaller connectors that go to the various disk drives of the computer. Most of them have four wires: two black, one red, and one yellow. Unlike the standard mains electrical wire color-coding, each black wire is a ground, the red wire is +5 V, and the yellow wire is +12 V.
4. Serial ATA power connectors: a 5-pin connector for components which use SATA power plugs. This connector supplies power at three different voltages: +3.3, +5, and +12 volts.
5. 6-pin Most modern computer power supplies include 6-pin connectors which are generally used for PCI Express graphics cards, but a newly introduced 8-pin connector should be seen on the latest model power supplies. Each PCI Express 6-pin connector can output a maximum of 75 W.

Efficiency of the computer power supply

Computer power supplies efficiency is generally about 70–75% efficient. That means in order for a 75% efficient power supply to produce 75 W of DC output it would require 100 W of AC input and dissipate the remaining 25 W in heat. Higher-quality power supplies can be over 80% efficient; higher energy efficient PSU’s waste less energy in heat, and requires less airflow to cool, and as a result will be much quieter. As of 2007, 93%-efficient power supplies are available.

For more information visit en.wikipedia.org/wiki/Computer_power_supply