Tesla was born in Smiljan, Austria-Hungary (now Croatia) on July 9, 1856. He studied engineering at two institutions in Austria-Hungary--Graz Technical University (now in Austria) and the University of Prague (now in the Czech Republic). Tesla left the University of Prague in 1880, without a degree, after his father died. He then worked for a short time for Austria-Hungary's telephone system in Budapest (now in Hungary). In 1882, Tesla moved to Paris, where he worked for the Continental Edison Company.
While at Graz Technical University, Tesla had seen a demonstration of a generator run as a direct-current (DC) motor. Direct current is electric current that flows in only one direction. During the demonstration, the brushes and the commutator of the motor sparked violently. The brushes are devices that conduct the current in a DC motor. The commutator continually reverses the current so that the motor continues to rotate in one direction. Tesla believed a motor without a commutator could be devised. In 1881, while walking in a park, Tesla suddenly got an idea for a simple way to produce such a device. In 1883, while on assignment for Continental Edison in Strasbourg, France, Tesla used his spare time to build his first polyphase (out-of-step) AC motor. In such a motor, coils are arranged so that when out-of-step alternating currents energize them, the resulting magnetic field rotates at a predetermined speed.
In 1884, Tesla left Europe for the United States and went to work for the inventor Thomas Edison. Edison respected the young engineer but the American inventor was a strong supporter of direct current (DC), and so he had little interest in Tesla's alternating current (AC) generation, transmission, and motor system. Tesla quit working for Edison after one year.
In 1887, Tesla started the Tesla Electric Company in New York City. There, he produced three complete systems of AC machinery. For each system, Tesla designed generators to supply the current, motors that use the current, transformers to raise and lower voltages, and a variety of devices to automatically control the machinery. Tesla received patents for his polyphase system of AC generators, transformers, and motors in 1888. That same year, he sold his patents to U.S. industrialist George Westinghouse. Tesla then worked at the Westinghouse Electric Company in Pittsburgh for a year to help develop commercial uses of the AC system. Tesla became a U.S. citizen in 1889.
In 1893, Westinghouse used Tesla's AC system to light the World's Columbian Exposition in Chicago. In 1895, Westinghouse's Niagara Falls Power Project used Tesla's generators and motors to harness the power...