<Table> <Tr> <Td> </Td> <Td> This article's lead section does not adequately summarize key points of its contents . Please consider expanding the lead to provide an accessible overview of all important aspects of the article . Please discuss this issue on the article's talk page . (May 2017) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article's lead section does not adequately summarize key points of its contents . Please consider expanding the lead to provide an accessible overview of all important aspects of the article . Please discuss this issue on the article's talk page . (May 2017) </Td> </Tr> <P> A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power . It is composed of semiconductor material usually with at least three terminals for connection to an external circuit . A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals . Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal . Today, some transistors are packaged individually, but many more are found embedded in integrated circuits . </P> <P> The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems . Julius Edgar Lilienfeld patented a field - effect transistor in 1926 but it was not possible to actually construct a working device at that time . The first practically implemented device was a point - contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley . The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things . The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement . </P>

The number of transistors on a particular integrated circuit