The History of the Transistor

The Little Invention That Made Big Changes - By Mary Bellis, About.com

The transistor is an influential little invention that changed the course of history in a big way for computers and all electronics.

History of Computers

You can look at a computer as being made of many different inventions or components. We can name four key inventions that made a huge impact on computers. An impact large enough that they can be referred to as a generation of change. The first generation of computers depended upon the invention of vacuum tubes; for the second generation it was transistors; for the third it was the integrated circuit; and the fourth generation of computers came about after the invention of the microprocessor.

The Impact of Transistors

Transistors transformed the world of electronics and had a huge impact on computer design. Transistors made of semiconductors replaced tubes in the construction of computers. By replacing bulky and unreliable vacuum tubes with transistors, computers could now perform the same functions, using less power and space.

Before transistors, digital circuits were composed of vacuum tubes. The story of ENIAC computer speaks volumes about the disadvantages of vacuum tubes in computers.

A transistor is a device composed of semi-conductor materials (germanium and silicon) that can both conduct and insulate Transistors switch and modulate electronic current. The transistor was the first device designed to act as both a transmitter, converting sound waves into electronic waves, and resistor, controlling electronic current.

The name transistor comes from the 'trans' of transmitter and 'sistor' of resistor.

The Transistor Inventors

John Bardeen, William Shockley, and Walter Brattain, were all scientists at the Bell Telephone Laboratories in Murray Hill, New Jersey. They were researching the behavior of germanium crystals as semi-conductors in an attempt to replace vacuum tubes as mechanical relays in telecommunications. The vacuum tube, used to amplify music and voice, made long-distance calling practical, but the tubes consumed power, created heat and burned out rapidly, requiring high maintenance.

The team's research was about to come to a fruitless end when a last attempt to try a purer substance as a contact point lead to the invention of the first "point-contact" transistor amplifier. Walter Brattain and John Bardeen were the ones who built the point-contact transistor, made of two gold foil contacts sitting on a germanium crystal. When electric current is applied to one contact, the germanium boosts the strength of the current flowing through the other contact. William Shockley improved upon their work creating a junction transistor with "sandwiches" of N- and P-type germanium. In 1956, the team received the Nobel Prize in Physics for the invention of the transistor.

In 1952, the junction transistor was first used in a commercial product, a Sonotone hearing aid. In 1954, the first transistor radio, the Regency TR1 was manufactured.

John Bardeen and Walter Brattain took out a patent for their transistor. William Shockley applied for a patent for the transistor effect and a transistor amplifier.