About Power Supplies

Power Supply is a general term used for a source of electrical power. When defining power supplies many factors have to be taken into consideration because there are so many different types. One fact that's true for all PSU's is that it supplies an electrical current for many components. This typically involves converting 120 or 240 volts of Alternating Current to a strictly regulated Direct Current for the electrical components. Since components take different power supply voltages (rails), Power Supplies are needed to regulate that Alternating Current. That is partly the reason that computers don't just run off of standard AC current, the sine waves that the AC form travels in are too powerful at 120 and 240 volts, smaller components need that regulation not to mention a non fluctuating current to function safely.

Many form factors exist for Power Supplies from redundant units that are used in server and raid solutions, to 1U and ATX form factors. Each type performs the same function but is designed for a specific form factor. Every power supply runs at a set rating, 200W, 300W, 400W etc, but at the same time does not hone to a specific wattage regulation, meaning PSU wattage is determined by the manufacturer of that unit.