1947

Silicon Transistor

John Bardeen (1908–1991), Walter Houser Brattain (1902–1987), William Shockley (1910–1989)

A transistor is an electronic switch: current flows from one terminal to another unless voltage is applied to a third terminal. Combined with the laws of Boolean algebra, this simple device has become the building block for microprocessors, memory systems, and the entire computer revolution.

Any technology that can use one signal to switch another on and off can be used to create a computer. Charles Babbage did it with rods, cogs, and steam power. Konrad Zuse and Howard Aiken did it with relays, and ENIAC used tubes. Each technology was faster and more reliable than the previous.

Likewise, transistors have several advantages over vacuum tubes: they use less power, so they generate less heat, they switch faster, and they are less susceptible to physical shock. All of these advantages arise because transistors are smaller than tubes—and the smaller the transistor, the bigger the advantage.

Modern transistors trace their lineage back to a device manufactured by John Bardeen, Walter Brattain, and William Shockley at AT&T’s Bell Laboratories in 1947. The team was trying to build an amplifier that could detect ultra-high frequency radio waves, but the tubes that they had just weren’t fast enough. So they tried working with semiconductor crystals, as radios based on semiconductor diodes called cat’s whiskers had been used since nearly the birth of radio in the 1890s.

A cat’s whisker radio uses a sharp piece of wire (the “whisker”) that’s jabbed into a piece of semiconducting germanium; by moving the wire along the semiconductor and varying the pressure, the semiconductor and the wire work together to create a diode, a device allowing current to pass in only one direction. The Bell Labs team built a contraption that attached two strips of gold foil to the crystal and then applied power to the germanium. The result was an amplifier: a signal injected into one wire was stronger when it came out of the other. Today we call this device a point-contact transistor.

For their discovery of the transistor, Bardeen, Brattain, and Shockley were awarded the Nobel Prize in 1956.

The first transistor ever made, built in 1947 by John Bardeen, William Shockley, and Walter H. Brattain of Bell Labs.