About this previous year paper
The uploaded file is a B.Tech (Semester III) Theory Examination – 2018–2019 question paper for the subject ELECTRONICS DEVICES AND CIRCUITS, Sub Code REC 302.
It contains 2 printed pages, carries a total of 70 marks, and is meant to be completed in 3 hours.
The paper examines a student’s understanding of semiconductor physics, electronic devices, MOSFET behavior, BJT parameters, amplifier analysis, and oscillator design. It includes both theoretical and analytical questions that test conceptual depth and practical knowledge.
PAGE 1 OVERVIEW
Page 1 contains the exam instructions and SECTION A.
SECTION A — Short Questions (2 × 7 = 14 Marks)
Students must answer all seven brief questions.
These questions focus on fundamental definitions and basic semiconductor concepts.
Topics include:
Semiconductors suitable for luminescence effect (LED-type materials)
Diffusion of carriers
Temperature effect on MOSFET drain current in linear region
Threshold voltage meaning
Zener breakdown vs Avalanche breakdown
Small signal model of JFET
Transconductance definition and importance
These questions check basic understanding of semiconductor device physics.
SECTION B — Medium-Length Questions (7 × 3 = 21 Marks)
While not fully visible in the scanned image, Section B typically targets:
Diode characteristics BJT configurations
Load-line analysis Biasing techniques
Frequency response of amplifiers MOSFET operation regions
This section tests a student’s analytical ability and theoretical knowledge.
PAGE 2 OVERVIEW
Page 2 provides SECTION C, which contains long, circuit-oriented and design-based questions requiring detailed explanations, diagrams, and mathematical reasoning.
SECTION C — Long Questions (7 marks each)
Students must attempt any one part of questions 6 and 7.
Question 6 — MOSFET Amplifiers & Capacitances
(a)
Explain in detail:
Single-stage MOS amplifier MOSFET internal capacitances (Cgs, Cgd, Cds)
Including:
Small-signal model Frequency response implications
Gain characteristics
(b)
Draw and explain a biasing circuit of a MOSFET amplifier.
Students must include:
Circuit diagram Operating point (Q-point) selection
Load line How biasing stabilizes amplifier performance
This tests design ability and MOSFET theory.
Question 7 — Oscillators & Feedback Topologies
(a)
Draw the circuit diagram of an LC oscillator and state the Barkhausen criterion (condition of oscillation).
Explanation must include:
Tank circuit (L and C) Positive feedback
Frequency of oscillation formula
(b)
Explain four types of feedback topologies using schematic diagrams:
Voltage-series Voltage-shunt
Current-series Current-shunt
Students must describe: Input/output sampling
Mixing method How feedback influences gain, bandwidth, distortion
OVERALL SUMMARY
The ELECTRONICS DEVICES AND CIRCUITS exam paper covers:
Semiconductor fundamentals
Carrier mechanisms
Diode & Zener behavior
BJT & MOSFET device physics
Amplifier theory & design
Biasing circuits
Oscillators
Feedback systems
It is ideal for engineering students preparing for electronics exams, competitive tests, or strengthening their foundational understanding of analog electronics.