Switching Converter, SMPS Transformers

A transformer is an electrical energy transfer device that either step up or down the voltage from one alternating-current circuit to one or more other circuits. Transformers are used for many functions, including raising the voltage from electric generators to enable long-distance electricity transmission and lowering the voltage of conventional power circuits to run low-voltage devices like doorbells and toy electric trains.

A current is induced in a second coil, known as the secondary, when the magnetic lines of force (also known as flux lines) build up and collapse with variations in current going through the primary coil in transformers. The number of turns in the secondary coil divided by the number of turns in the primary coil, known as the turns ratio, is multiplied by the primary voltage to determine the secondary voltage.