What Is the Purpose of a Transistor?

A transistor amplifies and switches electrical power and electronic signals. It is a semiconductor made of solid, non-moving parts that control the flow of electricity in circuits.

Transistors are used in the vast majority of electronics. Some of the first products that used them were transistor radios and hearing aids, which came into use in the early 1950s. Transistor radios work by amplifying signals. Radio stations take sounds recorded through a microphone and turn them into electrical signals. Those electrical signals travel through a circuit in the transistor radio, and the transistor then amplifies the signal, making it louder when it gets to the speaker. Transistors also changed how computers were made because they replaced vacuums, which were big, bulky and inefficient. Transistors are made of semiconducting materials, such as silicone or germanium. The most common transistors are made in a protective case and generally have three electrical leads.

The transistor was invented by William Shockley, John Bardeen and Walter H. Brattain of the Bell Telephone Laboratories in 1948. There were many failed attempts in creating the transistor, but the eventual realization of the idea forever changed many products, both in their efficiency and size, and gave way to making things dramatically cheaper and more readily available to the consumer.