What device transfers electric current from one circuit to another using electromagnetic induction, often changing voltage?

The device that transfers electric current from one circuit to another using electromagnetic induction while often changing voltage is a transformer. Transformers operate on the principle of electromagnetic induction to convert electrical energy from one voltage level to another, maintaining the same frequency. They consist of primary and secondary coils wound around a magnetic core. When an alternating current passes through the primary coil, it generates a magnetic field that induces a current in the secondary coil, allowing for the transfer of electrical energy between the two circuits.

This ability to change voltage makes transformers essential in power distribution systems, where they step up or step down voltage to efficiently transport electricity over long distances or to supply lower voltages for consumer use.