Alternating currents

Electric generators naturally generate alternating current, which rapidly alternates between one direction and the other, with intensity rising and falling like a sine wave. Tesla constructed an induction motor to do useful work.
 Nikola Tesla Croatia 1883 Alternating currents

Electric generators naturally generate alternating current, which rapidly alternates between one direction and the other, with intensity rising and falling like a sine wave. Tesla constructed an induction motor to do useful work.