Michael Faraday was one of the main innovators in the investigation of electromagnetism. He built on the work of Oersted and Ampere, establishing a symmetric relationship between electricity and magnetism. He discovered that if a current flowed in a wire close to a magnet with either one or the other free to move, then the free would would move. He constructed the first simple electric motor – a device for producing motion by passing an electric current througth a wire in a magnetic field. Shown below, the wire would perform circular motion around a magnet floating in mercury.
He alos discovered electromagnetic induction – that an electric field current be produced by moving a wire or coil in a magnetic field.
He built the first transformer – two coils of wire would on an iron core. A changing current in the primary coil produced by throwing a switch induced a changing magnetic field in the coil, which passed through the secondary coil, inducing a pulse of current, detected by a galvanometer.
