Fundamentals of Electronics Engineering - Unit 2

Jul 22, 2024

Fundamental of Electronics Engineering - Unit 2 Summary

Introduction

  • Complete syllabus of Fundamental of Electronics Engineering covered.
  • One-suit videos available for examination preparation.
  • This lecture covers BJT, JFET, and MOSFET.
  • Detailed topic-wise playlists available on the YouTube channel with PDF notes on Telegram channel.

Transistors Overview

  • Transistor: A three-terminal semiconductor device that amplifies or switches electronic signals.
    • Amplifiers in devices like radios and televisions replaced vacuum tubes.
  • Types of Transistors: BJT (Bipolar Junction Transistor), JFET (Junction Field Effect Transistor), MOSFET (Metal–Oxide–Semiconductor Field-Effect Transistor).

BJT (Bipolar Junction Transistor)

Types and Structure

  • Types: NPN & PNP
    • NPN: Single P-type layer sandwiched between two N-type layers.
    • PNP: Single N-type layer sandwiched between two P-type layers.
  • Three Terminals: Emitter (heavily doped), Base (lightly doped), Collector (moderately doped).
  • Configuration: Emitter > Base, Collector > Emitter & Base > Collector.

Operation Modes

  • Cut-Off Mode: Both junctions reverse biased - Transistor OFF.
  • Saturation Mode: Both junctions forward biased - Transistor ON.
  • Active Mode: Emitter-base forward biased, base-collector reverse biased - Transistor amplifies.

Advantage and Application

  • Advantages: Low power consumption, low cost, small size, higher physical resilience compared to vacuum tubes, produces less heat, and has higher efficiency.
  • Common in: Amplifiers, switches.

Field Effect Transistor (FET)

JFET (Junction Field-Effect Transistor)

  • Types: N-channel and P-channel.
  • Three Terminals: Source, Drain, Gate.
  • Modes: Cut-off, Saturation, Pinch-off.
  • Applications: Amplifiers, oscilloscope, voltage regulators, high impedance pre-amplifiers.
  • Features: High input impedance, low noise, suitable for high-sensitivity applications, temperature sensitivity.

MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)

  • Types: Enhancement mode and Depletion mode
    • Enhancement Mode: Requires VGS to form a channel.
    • Depletion Mode: Channel pre-formed; operates normally without VGS.
  • Advantages: High input impedance, low power consumption, faster switching speed, small size.
  • Applications: High-speed switching, amplifiers.
  • Modes: Depletion and Enhancement.

Transistor Configurations

  • Common-Base: Low input resistance, high output resistance, uses in high-frequency applications.
  • Common-Emitter: Medium input/output resistance, high power gain, commonly used for amplification.
  • Common-Collector: High input resistance, low output resistance, used for impedance matching.

Comparison

BJT vs JFET

  • BJT: Current controlled; operates with both electrons and holes.
  • JFET: Voltage controlled; operates mainly through majority carriers only.

BJT vs MOSFET

  • BJT: High current applications, low input impedance.
  • MOSFET: High power applications, high input impedance, faster switching.

Conclusion

  • Review: Unit 2 focused on BJT, JFET, and MOSFET, their types, characteristics, operational modes, configurations, and applications.
  • Resources: Detailed topic-wise videos and PDF notes are available on the YouTube channel and Telegram channel respectively for thorough understanding and exam preparation.

Watch the recommended master video on PN junction biasing to better understand the working principles.

Recommendations

  • Share videos with friends and classmates for broader learning and preparation benefits.
  • Ensure to go through the master video for detailed understanding before diving into the transistor unit.

Thank you for attending and supporting. Stay tuned for more one-suit lectures. Jai Hind, Jai Bharat.