Editing Bipolar junction transistor

NPN
PNP
BJT schematic symbols
Typical individual BJT packages. From top to bottom: TO-3, TO-126, TO-92, SOT-23

A bipolar junction transistor (bipolar transistor or BJT) is a type of transistor that uses both electrons and hole charge carriers. In contrast, unipolar transistors, such as field-effect transistors, only use one kind of charge carrier. BJTs rely on the junction between two semiconductor types, n-type and p-type, for their operation.

BJTs are manufactured in two types, NPN and PNP, and are available as individual components, or fabricated in integrated circuits, often in large numbers. The basic function of a BJT is to amplify current. This allows BJTs to be used as amplifiers, or switches giving them wide applicability in electronic equipment, including, computers, televisions, mobile phones, audio amplifiers, industrial control, and radio transmitters.

[1]

  1. ^ Paul Horowitz and Winfield Hill (1989). The Art of Electronics (2nd ed.). Cambridge University Press. p. 2. ISBN 978-0-521-37095-0.