In 1904, John Ambrose Fleming invented the first practical electron tube called the 'Fleming Valve', which is a diode rectifier. In 1906, Lee de Forest invented the audio later called the triode, which provided signal amplification.
On December 23, 1947, William Shockley, Walter Brattain and John Bardeen, of Bell Labs, announced their discovery of the point-contact germanium transistor to management.
