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Bipolar Junction Transistor

What is a Bipolar Junction Transistor?

A Bipolar Junction Transistor (BJT) is a three-terminal semiconductor device used for switching and amplification in electronic circuits. It consists of three layers of doped semiconductor material forming two p-n junctions, creating either an NPN or PNP configuration with base, collector, and emitter terminals. BJTs control a large current flow between collector and emitter by applying a small current to the base terminal, making them essential components in amplifiers, switches, and digital logic circuits.

Related Terms

Transistor

A transistor is a three-terminal semiconductor device that can amplify electrical signals or act as an electronic switch. It controls the flow of current between two terminals (collector and emitter in BJTs, or drain and source in FETs) based on the voltage or current applied to the third terminal (base or gate). Transistors are fundamental building blocks of modern electronics, used in everything from simple switching circuits to complex microprocessors and amplifiers.