Lee De Forest was an American engineer and inventor. Born Council Bluffs, Iowa, August 26, 1873. Died Hollywood, California, July 22, 1961.
De Forest invented the three-element electron tube, called the triode, that was the basis for the development of radio and the entire electronics industry. The triode, which De Forest patented in 1906, was at first used only as a detector in radio receivers. In 1912 the triode was used as a signal amplifier in telephone lines, making possible the first transcontinental telephone conversation. A year later, De Forest discovered that the triode could also be adapted for use as an oscillator, or generator of high-frequency alternating current. The use of triodes as oscillators and amplifiers completed the basic development of the radio.
De Forest was also one of the first radio broadcasters. In 1910 he broadcast the voice of Enrico Caruso in the first opera program to be transmitted over the air. In 1915, De Forest broadcast the human voice from Arlington, Va., to Paris, France, and in 1916 he produced the first news program.
From 1902 to 1952, De Forest patented more than 300 inventions. He perfected a method for producing sound on film in 1923 and invented the photoelectric cell in 1929. De Forest also helped develop television and radiotherapy.