PS is a part of major significance for any electric utility, and choosing the correct one may prolong the life of your gadget and prevent it from malfunctioning. Some devices may have a PS built-in, while others require a stand-alone utility that can be replaced or repaired if necessary. Modern PS are divided into two types - DC and AC. The first type has two subtypes. The first subtype is called linear. Linear PS receive the AC from an outlet, decrease the voltage, transform the current into direct and suppliy it to the inside parts of a gadget. It’s simple, but produces low power. If higher power is required, the second sub-type is utilized. It’s called switch-mode. Such PS follow the same steps to create DC, but then start switching it rapidly on and off at a very high rate, thus creating AC. Afterwards AC is processed in the PS again to produce DC of higher power. The second type is AC PS, it does not change the current type, only lowers the voltage received from the source. PS systems can have single and three phased output, and it determines how constant the flow of energy is.