(SEM-III) THEORY EXAMINATION 2019-20 ELECTRONIC DEVICES

This document is the B.Tech Semester III Theory Examination 2019–20 question paper for Electronic Devices (Sub Code: KEC301) under Dr. A.P.J. Abdul Kalam Technical University (AKTU).
The uploaded file contains two pages and is structured into three sections: SECTION A, SECTION B, and SECTION C.
The exam carries 100 marks and the duration is 3 hours.

The paper assesses the student's understanding of semiconductor physics, MOSFETs, BJTs, avalanche breakdown, fluorescence, carrier transport, lifetime, drift/diffusion mechanisms, Schottky diode, Ebers–Moll model, LED/Solar cell, and diode current equation.

SECTION A — Short Questions (10 × 2 = 20 Marks)

(Visible on Page 1 of the document)

Section A includes ten 2-mark questions that test fundamental knowledge of solid-state devices and semiconductor concepts.
The questions include:

Base width modulation

Direct vs Indirect semiconductors

Differences between EMOSFET and DMOSFET

Avalanche breakdown mechanism

BJT as a switch/amplifier

Fluorescence

Effective mass of carriers

Direct vs indirect recombination lifetime

Drift vs diffusion

Sheet resistance

These are direct conceptual questions presented in a table format on Page 1.

SECTION B — Long Answer Questions (Attempt Any 3 × 10 = 30 Marks)

(Located on Page 1)

Section B contains five descriptive questions, out of which students must attempt any three.
Topics include:

Direct and indirect bandgap semiconductors

PN junction diode characteristics

Working of N-channel MOSFET

Construction and characteristics of LED & Solar cell

Avalanche breakdown and related mechanisms

These questions require diagrams, characteristics curves, and proper theoretical explanations.

SECTION C — Advanced / Application-Based Questions (Q5–Q7)

(Shown on Page 2)

Section C contains three main questions (Q5, Q6, Q7), each having two alternatives (a or b).
Students must attempt one part from each question number.

Q5 — MOSFET Model / Optoelectronic Devices

(a) Explain & draw small-signal models of MOS transistor
OR

(b) Working principle & characteristics of LED and Solar Cell

Q6 — Ebers–Moll / Schottky Diode

(a) Explain Ebers–Moll model
OR

(b) Explain Schottky diode, construction & applications

Q7 — Continuity Equation / Diode Equation

(a) Derive continuity equation & diffusion length
OR

(b) Derive diode current equation for PN junction

These questions involve derivations, models, and deeper device physics understanding.

OVERALL SUMMARY OF THE DOCUMENT

The Electronic Devices (KEC301) question paper evaluates a student’s understanding of:

Semiconductor fundamentals

MOSFET operation & models

BJT working principles

Breakdown mechanisms

Drift & diffusion of carriers

Recombination processes

Optoelectronic devices: LED, Solar cell

Ebers–Moll transistor model

Schottky diode

Continuity equation

Diode current equation

The paper strictly follows the AKTU 3-section structure:

SECTION A: Quick conceptual recall

SECTION B: Descriptive theory & device explanations

SECTION C: Derivations, models, and advanced semiconductor analysis

The uploaded file contains two clearly readable pages with all questions properly organized.