Nikola Tesla invented.
Nikola Tesla ( Никола Тесла 10 July 1856 -- 7 January 1943 ) was a Serbian-American inventor , electrical engineer , mechanical engineer , physicist , and futurist who is best known for his contributions to the design of the modern alternating current ( AC ) electricity supply system . His alternating current ( AC ) induction motor and related polyphase AC patents , licensed by Westinghouse Electric in 1888 , earned him a considerable amount of money and became the cornerstone of the polyphase system which that company would eventually market . Attempting to develop inventions he could patent and market , Tesla conducted a range of experiments with mechanical oscillators/generators , electrical discharge tubes , and early X-ray imaging . Tesla became well known as an inventor and would demonstrate his achievements to celebrities and wealthy patrons at his lab , and was noted for his showmanship at public lectures .