Power transformers are electrical devices used to transfer electrical energy between two or more circuits through electromagnetic induction. A varying current in one coil of the transformer produces a varying magnetic field, which induces a varying voltage in the second coil. Power can be transferred between these two coils through the magnetic field, without the need of any metallic connection between the two circuits. Power transformers can either be step up or step down, meaning they can increase or decrease the alternating voltages in power applications, as required. In fact, power transformers are used in various stages of the power generation process, right from the power generating stations to the end users, by stepping up and stepping down voltages at various points. It is only due to these power transformers that we can receive safe amounts of electricity into our homes and offices today!