Lee de Forest invented vacuum tubes.
The Audion of Lee De Forest. Lee De Forest (1873–1961) was a remarkable American inventor with over 180 patents to his credit. He took credit for the Audion, first vacuum triode, a vacuum tube that takes relatively weak electrical signals and amplifies them.
Lee De Forest was born August 26, 1873 in Council Bluffs, Iowa. He invented the Audion vacuum tube, which made possible live radio broadcasting and became the key component of all radio, telephone, radar, television, and computer systems.
The first vacuum tube used in radio was the thermionic diode or Fleming valve, invented by John Ambrose Fleming in 1904 as a detector for radio receivers. It was an evacuated glass bulb containing two electrodes, a heated filament and a plate (anode).