Nikola Tesla (1856–1943) was an inventive genius, a contemporary and competitor of Edison. He developed electrical alternating current, the universal standard of electrical transmission used today. He also developed technology earlier than Marconi that could have been adapted to radio. He also developed the induction motor, discovered the rotating magnetic field, and was responsible for numerous other practical inventions. Tesla had an idea for sending electricity wirelessly around the world. He was originally supported in this work by Westinghouse, but when it was discovered he was going to supply the world with electricity for free, the support was cancelled.

Tesla is perhaps best known for the Tesla Coil. This type of coil produces high voltage discharges that are low in amperage, making them safe to be around for healthy people. Although most people know of these devices from exhibits in museums and for shooting what appears to be lightning in old horror movies, they were also used wireless electrical transmission, early wireless telegraphy, some questionable medical devices, Kirlian photography, and many other items.

Toward the end of his life Tesla claimed to have created an energy weapon that was called a “death ray” in the media. Some people believe that the US government is secretly testing such a device.