“What have you done with my child [the radio broadcast]? You have debased this child..."
Lee De Forest, Chicago Tribune (1946)
In 1904, British physicist-John Ambrose Fleming (1849-1945) developed what he called an "oscillation valve." Later rechristened the "diode," it Is universally recognized as the first true electronic device. Two years later, building on Fleming's work, American electrical engineer Lee De Forest (1873-1961) created the Audion vacuum tube—the first valve amplifier.
De Forest's major innovation was in creating a valve that would not only rectify the AC current, but boost it. The Audion contained the same filament, cathode and plate/anode design of the Fleming valve, but placed between them was a zigzag of wire called a grid. A small electric current applied to the grid would result in much current shifting from the filament to the plate. Thus was born the first electrical amplifier. With its three active electrodes, De Forest's valve amplifier evolved into what would later become known as the triode, and would be central to the creation of most of the important developments in electronics over the next half century.
De Forest frequently ran into patent disputes, and evidently spent much of the fortune he amassed in assorted lawsuits. There was a clear similarity between the Fleming tube and the first Audion valves, and decades of costly and disruptive litigation followed. It was not until 1943 that, having first sided with Fleming, the U.S. Supreme Court ruled that, on a legal technicality, Fleming's patent was invalid. In 1946, the importance of De Forest's invention was acknowledged when his work on the triode was awarded the prestigious Edison Medal of the American Institute of Electrical Engineers.
