Magnet Academy: Lee De Forest

American inventor Lee De Forest was a pioneer of radio and motion pictures. He received more than 300 patents over the course of his lifetime, the most important of which was for a three-electrode vacuum tube, or triode, that he called the Audion. The invention of the Audion, a device capable of amplifying and modulating electromagnetic signals that could also function as an oscillator, was a crucial step in the early electronics industry. Until the invention of the transistor in 1948, the triode was featured in almost all electronic equipment.