Description

The NPN Bipolar Junction Transistor (BJT) is a three-terminal semiconductor device widely used for signal amplification and electronic switching applications. It is suitable for low- to medium-power circuits and is commonly found in amplifiers, oscillators, logic circuits, motor drivers, relay control circuits, and embedded systems. Popular models include the BC547, BC548, 2N2222, and TIP122, depending on the required current and power rating.