A transformer is a device that transforms AC voltage, current, and impedance. When an AC current is passed through the primary coil, an AC magnetic flux is generated in the iron core (or magnetic core), causing a voltage (or current) to be induced in the secondary coil. The transformer is composed of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary winding, and the remaining windings are called the secondary winding. In a generator, whether the coil moves through the magnetic field or the magnetic field moves through the fixed coil, it can induce an electric potential in the coil. In both cases, the value of the magnetic flux remains unchanged, but the amount of magnetic flux intersecting with the coil is different. Change is the principle of mutual induction. The transformer is a device that uses electromagnetic mutual inductance to transform voltage, current, and impedance.
Classified by cooling method: dry (self-cooling) transformers, oil-immersed (self-cooling) transformers, fluoride (evaporative cooling) transformers.
Classified by the moisture-proof method: open transformer, potted transformer, sealed transformer.
Classified by core or coil structure: core transformer (insert core, C-type core, ferrite core), shell transformer (insert core, C-type core, ferrite core), Toroidal transformers, metal foil transformers.
According to the number of power phases: single-phase transformer, three-phase transformer, multi-phase transformer.
Classified by a purpose: power transformers, voltage regulating transformers, audio transformers, intermediate frequency transformers, high-frequency transformers, pulse transformers.