<P> Independently of Faraday, the Hungarian Ányos Jedlik started experimenting in 1827 with the electromagnetic rotating devices which he called electromagnetic self - rotors . In the prototype of the single - pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic . He also may have formulated the concept of the dynamo in 1861 (before Siemens and Wheatstone) but didn't patent it as he thought he wasn't the first to realize this . </P> <P> A coil of wire rotating in a magnetic field produces a current which changes direction with each 180 ° rotation, an alternating current (AC). However many early uses of electricity required direct current (DC). In the first practical electric generators, called dynamos, the AC was converted into DC with a commutator, a set of rotating switch contacts on the armature shaft . The commutator reversed the connection of the armature winding to the circuit every 180 ° rotation of the shaft, creating a pulsing DC current . One of the first dynamos was built by Hippolyte Pixii in 1832 . </P> <P> The dynamo was the first electrical generator capable of delivering power for industry . The Woolrich Electrical Generator of 1844, now in Thinktank, Birmingham Science Museum, is the earliest electrical generator used in an industrial process . It was used by the firm of Elkingtons for commercial electroplating . </P> <P> The modern dynamo, fit for use in industrial applications, was invented independently by Sir Charles Wheatstone, Werner von Siemens and Samuel Alfred Varley . Varley took out a patent on 24 December 1866, while Siemens and Wheatstone both announced their discoveries on 17 January 1867, the latter delivering a paper on his discovery to the Royal Society . </P>

How does an electric generator generate an electric current