A transformer are an electrical device that uses electromagnetic mutual inductance to transform voltage, current and impedance. A transformer uses the principle of electromagnetic induction to change the AC voltage. The components of the transformer are primary coil, secondary coil and iron core (magnetic core). In electrical equipment and wireless circuits, it is commonly used for lifting voltage, matching impedance, safety isolation, etc. In a generator, the electric potential can be induced in the coil whether the coil moves through the magnetic field or the magnetic field moves through the fixed coil. The main functions are: voltage transformation, current transformation, impedance transformation, isolation, voltage regulation (magnetic saturation transformer) and so on. As the basic equipment of transmission and distribution, transformers are widely used in industry, agriculture, transportation, urban communities and other fields.