Spark generator. A magnetic spark generator made in 1832 by British scientist Michael Faraday (1791-1867). It consists of an insulated copper coil wound around a bobbin. This is held between the poles of stacked permanent magnets. Rotating the bobbin sharply would produce an instantaneous current and enough voltage for a spark to be generated across a small gap between the open ends of the wire in air. This was a demonstration of the generation of electricity from a magnetic field and is the forerunner of the dynamo. This artefact is preserved at the Royal Institution, London.