In 1891, Nikola Tesla became an American citizen and obtained 10 U.S. patents, including one for his Tesla Oscillator, better known as the Tesla Coil. A high-frequency AC transformer capable of creating high voltage at low current, the Tesla Coil was one of Tesla's most significant inventions. Tesla used it as a component of the first generation of transmitters for wireless technology. In 1943, the United States Supreme Court decreed that Tesla's 1891 patent for the oscillator pre-dated G. Marconi's work and thus validated Tesla as the 'Father of Radio,' contradicting the 1909 Nobel Prize Committee award to Guglielmo Marconi for wireless work. The high-frequency oscillator was used in electrical experiments including wireless phosphorescence, wireless lighting, X-radiation, high-frequency AC phenomena, and the wireless transmission of electrical energy. Ultimately, the physics of the Tesla Coil was employed in all radio and television receivers.