Transformers in a AC circuit helps in altering the voltage of the circuit.

A transformer is a passive electrical device that transfers one  circuit to another. It consists of two electrically isolated coils and operates according to Faraday's principle of mutual inductance. It converts electrical energy into magnetic energy on the primary side and returns it from magnetic energy to  electrical energy on the secondary side.  The function of the transformer in AC switching is to be able to increase or decrease the AC voltage, but the power remains constant. A step-up transformer converts high voltage  to low voltage, and  a step-up transformer converts low voltage to high voltage.  A step-down transformer can be defined as an object that converts high voltage and low current to low voltage and high current. The number of wire windings of  the coil on the primary side is large, and the number of wire windings of  the coil on the secondary side is small. Transformers are equipment used in almost all electrical equipment. It is intended to transfer energy from the high voltage region to the low voltage. This means changing the voltage from high voltage to low voltage.