A transformer (in French: Transformateur) or a transformer (in English: Transformer) is a device that transfers electrical energy between two or more coils through electromagnetic induction. In this way, a variable current in the primary winding of the transformer produces a variable magnetic field, which leads to a voltage in the secondary winding.
Power can be transferred between two coils through a magnetic field without any metal connection between the two circuits. In 1831, Faraday’s law of induction described this effect. Transformers are used to increase or decrease alternating voltage in electrical projects.
Since the invention of the first permanent transformer in 1885, transformers have been used to transmit, distribute, and exploit alternating current electrical energy.  The range of transformers has expanded in terms of size from transformers less than one cubic centimeter to grid connection units. which weighs hundreds of tons.