bipolar junction transistor

A bipolar junction transistor (BJT) is a type of electronic switch or amplifier made of three layers of semiconductor material. It has three parts: the emitter, base, and collector. By applying a small electrical signal to the base, the BJT can control a much larger current flowing between the emitter and collector. This ability allows it to amplify signals or switch electronic devices on or off. BJTs are fundamental components in many electronic devices, enabling functions like amplification in audio systems and switching in digital circuits.