The transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil, and the iron core. The iron core is the main magnetic circuit part in the transformer. It is usually formed by stacking hot-rolled or cold-rolled silicon steel sheets with high silicon content and coated with insulating paint on the surface. The iron core and the coil wound on it form a complete electromagnetic induction system