Bipolar Junction Transistor

What Does Bipolar Junction Transistor Mean?

A bipolar junction transistor (BJT) is a type of semiconductor that uses both electron and hole charge carriers. They are used to amplify electric current. BJTs are available both alone or packaged into integrated circuits (ICs). BJTs are widely used in amplifiers for a large amount of everyday electronic equipment.


A bipolar junction transistor is also known as a bipolar transistor.

Techopedia Explains Bipolar Junction Transistor

A bipolar junction transistor is a type of semiconductor that is formed by joining two types of semiconductors, P-type and N-type, with a third base. This base can modulate the amount of electricity flowing through it. These devices allow for the amplification of electric current in a very small space. BJTs are available on their own or made as integrated circuits.

The BJT was invented by William Shockley at Bell Labs in 1948 and was a major breakthrough in electronics. It allowed electronics manufacturers to construct smaller, cheaper devices. Its effect was seen first with the introduction of transistor radios. BJTs eventually led to the development of microprocessors and the modern computer industry when it was realized that transistors could be used to build logic gates.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…