Pixii's magneto-electric machine, 1832.
© Science Museum / Science & Society Picture Library
A reproduction of the mechanical generator made by French instrument maker Hippolyte Pixii (1808-1835). Michael Faraday discovered the principles of electromagnetic induction in 1831. Pixii's magneto-electric machine, developed in 1832, was the first practical mechanical generator of electrical current to use the concepts demonstrated by Faraday, and the first direct current (dc) generator. It is hand-cranked, and uses a set of gears to turn a large horseshoe-shaped permanent magnet.