Power Supply Edit
By Sophie Burchell
The power supply unit (PSU) is what gives life to the computer. It converts the power from the household electrical outlets, which run on alternate currents (AC), into direct current energy (DC). This smooth flow of electricity is necessary to the running of a computer. Wires carry the electricity from the PSU directly to the motherboard, as well as the optical drive and other drives. The RAM and less high-power aspects of the computer get their power rerouted from the motherboard. This crucial component of the computer also regulates overheating by regulating the voltage. For more info go here.
The power supply works by filtering the alternate currents. The electricity passes through a rectifier that turns it into DC voltage, which is then filtered through an electronic filter that smooths out some of the remaining pulses.
Aside from these basic similarities, there are many types of power supplies that work quite differently. The linear power supply takes any amount of AC voltage, filters it, and reduces it to the lower DC voltage that the computer can take. The excess electricity is released as heat. While simple and adaptable, the linear PSU is bulky and inefficient. Additionally, it can get quite warm, and the box containing the unit requires a fan.
The switching power supply does not waste power. Instead of getting the desired reduced voltage by releasing the extra electricity, it switches the current on and off up to a thousand times per second. No current has to be released. While more expensive and complicated, the switching PSU is much more efficient and releases no heat. Read more about it here.
Over 2.5 billion power supplies are used in the United States. They can vary from 90% efficient to only 20% efficient. This inefficiency comes from in the loss of electricity in the conversion from AC to DC, most often found in linear power supplies. This inefficiency results in the waste of 2% of U.S. electricity. Efforts are being made to create more widespread efficiency in power supplies, such as the widespread and accessible use of switching power supplies. This would save both money and the environment. Learn more here.