Nikola Tesla (Serbian Cyrillic: Никола Тесла) (10 July 1856 – 7 January 1943) was an inventor, mechanical and electrical engineer. Born in Smiljan, Croatian Krajina, Austrian Empire, he was an ethnic Serb subject of the Austrian Empire and later became an American citizen. Tesla is best known for many revolutionary contributions in the field of electricity and magnetism in the late 19th and early 20th centuries. Tesla's patents and theoretical work contributed to the modern alternating current electric power (AC) systems, including the polyphase power distribution systems and the AC motor.
He was widely respected as an electrical engineer but his unsuccessful forays into trying to transmit electrical power wirelessly and his eccentric personality, seemingly unbelievable and sometimes bizarre claims about possible scientific and technological developments made some regarded as a mad scientist. Never having put much focus on his finances, Tesla died impoverished at the age of 86. After his death many of his achievements have been used, with some controversy, to support various pseudosciences, UFO theories, and early New Age occultism.
The SI unit measuring magnetic flux density or magnetic induction (commonly known as the magnetic field ), the tesla, was named in his honour (at the Conférence Générale des Poids et Mesures, Paris, 1960).
Tesla is honored in Serbia and Croatia, as well as in the Czech Republic (he was awarded the highest order of the White Lion by Czechoslovakia) and in unofficial ways in his adopted home, the United States.