Power electronics This article refers to the technology of power electronics . For the musical genre see power electronics Power electronics is the technology associated with the efficient conversion , control and conditioning of electric power by static means from its available input form into the desired electrical output form . Introduction Power electronic converters can be found wherever there is a need to modify the electrical energy form ( i.e modifiy its voltage , current or frequency ) . Therefore , their power range from some milliwatts ( as in a mobile phone ) to several megawatts ( e.g to supply power to a train ) . With `` classical '' electronics , electrical currents and voltage are used to carry information , whereas with power electronics , they carry power . Therefore the main metric of power electronics becomes the efficiency . Nowadays , the conversion is performed with semiconductor switching devices such as diodes , thyristors and transistors . In contrast to electronic systems concerned with transmission and processing of signals and data , in power electronics substantial amounts of electrical energy are processed . An AC/DC converter ( rectifier ) is the most typical power electronics device found in many consumer electronic devices , e.g. , television sets , personal computers , battery chargers , etc . The power range is typically from tens of watts to several hundred watts . In industry the most common application is the variable speed drive ( VSD ) that is used to control an induction motor . The power range of VSDs start from a few hundred watts and end at several megawatts . The power conversion systems can be classified according to the type of the input and output power AC to DC ( rectification ) DC to AC ( inversion ) general case of ( Class-D ) amplifier DC to DC ( regulation ) a special case of ( Class-D ) amplifier AC to AC ( rectification followed by inversion or directly using a matrix converter ) , special case : UPS Principle As efficiency is at a premium in a power electronic converter , the losses that a power electronic device generates should be as low as possible . The instantaneous dissipated power of a device is equal to the product of the voltage across the device and the current through it ( P=U\times I ) . From this , one can see that the losses of a power device are at a minimum when the voltage across it is zero ( the device is in the On-State ) or when no current flows through it ( Off-State ) . Therefore , a power electronic converter is built around one ( or more ) device operating in switching mode ( either On or Off ) . With such a structure , the energy is transferred from the input of the converter to its output by bursts . Applications Power electronic systems are virtually in every electronic device . For example , around us : DC/DC converters are used in most mobile devices ( mobile phone , pda ... ) to maintain the voltage at a fixed value whatever the charge level of the battery is . AC/DC converters are used every time an electronic device is connected to the mains ( computer , television , ... ) References Categories : Electronics | Power electronics In other languages : Deutsch | Español | Français | Nederlands | 日本語 | Polski | Português | Tiếng Việt | 中文 