The development of electronics, according to Zworykin, could be divided into three epochs. “In the first, beginning with DeForest’s invention of the audion in 1906 and ending with the First World War, electron currents were controlled in vacuum tubes in much the same manner as a steam valve controls the flow of steam in a pipe,” he explained. “No more attention was paid to the behavior of the individual electrons in the tube than is customarily expended on the motion of the individual steam molecules in the valve.”
