7. Overview of Bipolar Junction Transistors (BJTs)
Bipolar Junction Transistors (BJTs) are current-controlled, bipolar devices crucial for signal amplification and digital switching. They come in two types: NPN and PNP, and operate based on the interaction of p-n junctions. Key characteristics include their configurations, modes of operation, and applications in both analog and digital circuits, with a notable comparison to MOSFETs.
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What we have learnt
- BJTs are current-controlled bipolar devices that utilize electrons and holes as charge carriers.
- They operate in three major regions: active for amplification, cut-off for OFF state, and saturation for ON state.
- BJTs come in three configurations: Common Emitter (CE), Common Base (CB), and Common Collector (CC), each with distinct characteristics and applications.
Key Concepts
- -- BJT
- A Bipolar Junction Transistor is a current-controlled device that uses both electron and hole charge carriers, essential for amplification and switching.
- -- NPN Transistor
- A type of BJT where the majority charge carrier is electrons, requiring positive base-emitter voltage for operation.
- -- PNP Transistor
- A type of BJT where the majority charge carrier is holes, requiring negative base-emitter voltage for operation.
- -- Current Gain (β)
- The ratio of collector current to base current in a BJT, typically ranging from 20 to 200.
- -- Configurations
- The arrangement of BJTs, including Common Emitter, Common Base, and Common Collector, each with unique input/output characteristics.
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