A dreamer who combined self-discipline and precision with a poetic touch, Tesla began as an engineering student at the Technical University at Graz, Austria. When he viewed the Gramme dynamo, which operated as a generator and, when reversed, became an electric motor, Tesla conceived a way to use alternating current to advantage. Later, he visualized the principle of the rotating magnetic field. He also developed plans for an induction motor that would become the first step toward the ac induction motor, which he constructed in 1883. In 1885, one year after arriving penniless in New York, Tesla sold the rights to his polyphase system of ac dynamos, transformers, and motors to George Westinghouse. After establishing his own laboratory, Tesla invented the "Tesla coil," which is still widely used in radio and television sets and other electronic equipment.