Nikola Tesla who was the precursor of the use of AC, was an immigrant from Eastern Europe. He arrived in New York in 1884, with only a book of poetry, docen mastery of a language, and almost in poverty.In an LC circuit fed AC produces resonance, this means that even a small oscillation of tension, would cause a large amount of electric charge.Tesla was the first to describe a network of tuned resonant circuits and antennas; it's like the radio and TV work.In an RLC circuit, supplied with AC, voltage oscillations and resonance, can be a serious problem; this when we have high frequencies.George Westinghouse, was an inventor and businessman, who favored the ACs Tesla and support him in the War of the Currents against Thomas Edison. Tesla was the winner.An advantage of the AC, is the reduction of losses at the time of transmission. The key to efficient transmission, is to make the maximum voltaje.The AC has the facility to be raised or lowered; this compared with DC; It is an important advantage.Years before its creation, Tesla had imagined vacuum tubes coated with phosphor and glass tubes filled with gas; were fluorescent lights and neon lights.Tesla was denied several merits of own inventions; but he was not interested in patents, his passion for inventing was bigger. His recognition would come later.Nikola Tesla as well as Da Vinci, was a saint of engineering; but nevertheless; died almost forgotten, alone and poor in New York.