Transformer

A transformer is a passive electrical device that transfers electrical energy from one circuit to another through electromagnetic induction, using a varying current in one coil to produce a varying magnetic flux that induces a voltage in another coil wound on the same core. The underlying principle was discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832. The first widely used transformer design was the induction coil, invented by the Irish clergyman Nicholas Callan of Maynooth College in 1836, and the first efficient closed-core transformer suited to power distribution was developed in 1885 by the Hungarian engineers Karoly Zipernowsky, Otto Blathy and Miksa Deri at the Ganz factory.