Nikola Tesla invented the alternating current electrical system and the Tesla coil. He also discovered radar and X-ray technology and the rotating magnetic field.
The rotating magnetic field is the backbone of alternating current machinery in modern day. Tesla developed and patented his alternating current electrical system, which successfully competed with Thomas Edison's system, and later sold it to George Westinghouse. Tesla's power system is still used worldwide today. He also invented the Tesla coil in 1891, an apparatus that uses capacitors and inductors to produce alternating currents and led to many new developments in radio technology. Tesla planned a hydroelectric plant for Niagara Falls and attempted to build a large information sharing system with an electrical tower, but financial issues kept him from success.