Bipolar Junction Transistor | TechAmbitionX | Notes By BILRED
Bipolar Junction Transistor (BJT) — TechAmbitionX 🔹 1. What is a Transistor (BJT)? BJT (Bipolar Junction Transistor) is a three-layer, three-terminal semiconductor device that controls a large current using a small one. Simply put — a small base current controls a much larger collector current. Terminals: Emitter (E): Emits charge carriers. Base (B): Thin, lightly doped control layer. Collector (C): Collects charge carriers. 🔹 2. Types of BJTs There are two main types based on how the layers are arranged: NPN Transistor → Current flows from Collector → Emitter (majority carriers = electrons) PNP Transistor → Current flows from Emitter → Collector (majority carriers = holes) 🔹 3. Basic Principle When a small current is applied to the base-emitter junction , it allows a much larger current...