What are transformers?

Transformers

A transformer is a device that transfers electrical energy from one circuit to another by electromagnetic induction (also called transformer action). It is most often used to step up or step down voltage. Occasionally, it is used as an isolating device to eliminate a direct mechanical electrical connection between the power source and the loads. The electrical energy is always transferred without a change in frequency but may involve changes in the effective value of voltage and current. Because a transformer works on the principle of electromagnetic induction, it must be used with an input source that varies in amplitude.