Magneto-electric machine, known as 'Pixii's machine'

In 1832 the instrument maker Antoine Hippolyte Pixii made a machine for André Marie Ampère regarded as the first alternator applying Faraday’s discovery of electromagnetic induction. A coil’s exposure to a variable magnetic field induces an electric current. In Pixii’s machine, a crank turning a powerful horseshoe magnet produces the magnetic field. The immobile coil is above the magnet. The variations in the magnetic field to which it is subjected generate an induced alternating current. But at that time only direct current could have applications such as telegraphy. By adding a switch, serving as a rectifier and supplying an exterior circuit with a current always flowing in the same direction, Ampère transformed alternating current into direct current and opened a range of applications for Pixii’s machine.