This Day in History
December 29, 1939
Shockley Makes Historic Notebook Entry
William Shockley records in his laboratory notebook that it should be possible to replace vacuum tubes with semiconductors. Eight years later, he, Walter Brattain and John Bardeen at AT&T Bell Laboratories successfully tested the point-contact transistor. Shockley developed much of the theory behind transistor action, and soon postulated the junction transistor, a much more reliable device. It took about ten years after the 1947 discovery before transistors replaced vacuum tubes in computer design as manufacturers learned to make them reliable and a new generation of engineers learned how to use them.