Lilienfield’s transistor was the first sign for progress away from vacuum tubes in computers.  The second great breakthrough came in 1947, when the first point-contact germanium transistor was created by three physicists at Bell laboratories.  This transistor was much smaller than vacuum tubes, and cheaper to maintain.  In 1950, on of these same physicists, William Shockley, invented the bipolar junction transistor, which is more reliable than the point-contact versions.  Shortly after this, the germanium in transistors was changed to silicon, since silicon was cheaper and easier to work with.  The use of semiconducting materials was one of the key technologies involved in transistors. 

 Transistors act as switches to an electrical current. They are much smaller in scale than the vacuum tubes they replaced, as well as many times more powerful.  They ever decreasing size of the transistor is one of the key reasons that processors continue to become more powerful.

Next : 1939 - The first automatic digital computer is designed

All material and images on these pages are copyright Joseph and Ed. This page was developed for the Thinkquest1999 competition.