Transistors are used in almost every electronic device now made. A transistor is an electrically controlled resistor that has three terminals: two for the end-to-end flow of electrical current and one for the electrical signal that controls its end-to-end resistance. John Bardeen (1908–1991), Walter H. Brattain (1902–1987), and William B. Shockley (1910–1989) invented the transistor in 1947. Billions of transistors have been made since then, many of them inside the integrated circuits that make up the processors and memory modules of modern computers. The transistor is such an important device, and its invention was such a scientific breakthrough, that its three inventors were awarded the Nobel Prize in 1956.

Impact of the Transistor

Since early in the twentieth century, vacuum tubes had been used in electronic circuits, like amplifiers, to make electronic equipment, like radios. Even the first computer, built before the invention of the transistor, was made with...