Lee de Forest

By Julien Moreau

Lee de Forest was born on August 26, 1873, in Council Bluffs, Iowa, the son of a Congregational minister who hoped his boy would enter the clergy. The boy had other plans. At Yale's Sheffield Scientific School he earned a PhD in 1899 with a dissertation on the reflection of Hertzian waves, then threw himself into the frantic early race for wireless telegraphy, working for Western Electric and founding the American De Forest Wireless Telegraph Company. In 1904 the British physicist John Ambrose Fleming patented a two-element vacuum tube, the diode, which could detect radio signals but not amplify them. De Forest saw the missing piece. In 1906, in his New York laboratory, he took Fleming's tube and inserted a third electrode — a fine wire grid — between the heated filament and the plate. The result was the Audion. A tiny voltage applied to the grid controlled a far larger current flowing from filament to plate, which meant a feeble incoming signal could emerge strengthened, again and again, in cascade. For the first time in history, an electrical signal could be amplified. He filed the patent in January 1907 (U.S. Patent 879,532), and the three-element vacuum tube — the triode — became the founding device of the electronic age. De Forest himself never fully understood what he had made. He grasped detection and amplification but missed the principle of feedback; it was the young Edwin Armstrong who took the Audion, fed its output back into its input, and produced the regenerative receiver that made radio practical — then sued de Forest in a patent war that dragged through the courts for two decades and ended, astonishingly, with de Forest winning on a technicality the engineers knew was wrong. Business was never his gift. He sold Audion rights for a pittance, faced a 1912 federal trial for stock fraud over his wireless company (he was acquitted), and watched others build fortunes on his glass tube. Yet he kept pushing the medium forward. In 1910 he broadcast opera singers, including Enrico Caruso, from the Metropolitan Opera House. In 1916 his station 2XG aired presidential election returns, one of the first news broadcasts in history. In the 1920s he developed Phonofilm, a sound-on-film process, though Hollywood ultimately chose rival systems. He collected over 300 patents, an Academy Award for his pioneering contributions, and the self-styled title “Father of Radio,” contested to this day. He died in Hollywood on June 30, 1961, largely eclipsed by the men who had amplified his amplifier.

Impact on civilization

The Audion made the twentieth century possible. Before 1906, electrical signals could travel but never grow stronger; every telephone call faded with distance, every radio whisper died in the wire. Amplification broke that law. Long-distance telephony, radio broadcasting, radar, television, and the first electronic computers all descend directly from de Forest's grid: the ENIAC's 17,000 vacuum tubes were Audions in spirit. The triode turned electricity from a utility into a language — signals that could be shaped, multiplied, and computed with — and thereby founded electronics as a field. The vacuum tube itself was eventually displaced by the transistor, but nothing about the modern world, from the broadcast networks that carried the century's news to the digital machines that followed, exists without the moment a wire grid learned to command a current. De Forest never profited in proportion — he sold his patents cheaply and watched others take the fortune — but the rubric does not grade business acumen. It grades the grid: the device that turned electricity into a medium, founded the electronic century, and still sits, in transistor form, inside every machine that computes.