(SEM-III) THEORY EXAMINATION 2019-20 ELECTRONICS ENGINEERING

This document is the B.Tech SEM–III Theory Examination 2019–20 question paper for Electronics Engineering (Sub Code: KOE038) under Dr. A.P.J. Abdul Kalam Technical University (AKTU).
The exam is of 3 hours duration, carries 100 marks, and the uploaded file contains three pages, all clearly divided into three sections: SECTION A, SECTION B, and SECTION C.

The question paper examines fundamental concepts of semiconductor physics, diodes, rectifiers, amplifier parameters, FET characteristics, CRO operation, tunnel diode, varactor diode, rectifier waveforms, op-amp parameters, and oscilloscopes.

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

(Visible on Page 1, table format)

Section A contains ten 2-mark questions, covering the basics of semiconductor devices and electronic measurements. These include:

Effect of temperature on free electrons in a semiconductor

Difference between Zener breakdown and avalanche breakdown

Zener diode regulator problem with varying input & load resistance

Average current, RMS current & efficiency of half-wave and full-wave rectifiers

Relationship between ICBO and ICO in BJT

How FET works as a voltage-controlled resistor

Meaning of unity gain buffer

Definition of slew rate in OP-AMP

Comparison of analog vs digital instruments

Applications of CRO

These 10 questions test the student’s foundational understanding.

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

(Located on Page 1 bottom)

Students must attempt any three out of five 10-mark questions.
Topics include:

Full-wave rectifier analysis:

Avg voltage

DC output

AC input power

Rectification efficiency

Percentage regulation

Output waveform sketch (waveform shown on Page 2)

Operation of tunnel diode & varactor diode (with diagrams)

Calculation of VCEQ and ICQ for the BJT bias circuit given on Page 2

Op-amp terms: Slew rate, Virtual ground, CMRR

Measurement of voltage, frequency, and phase using CRO

Also includes Lissajous pattern example with horizontal freq = 1800 Hz and tangent count = 5 vertical & 6 horizontal

These questions require circuit analysis, waveform understanding, and descriptive explanations.

SECTION C — Attempt ONE from Each (Q4, Q5, Q7)

(Shown on Page 2 and Page 3)

Section C contains three main questions (Q4, Q5, Q7), each having two alternatives (a or b). Students must attempt one part from each.

Q4 — Rectifiers / Tunnel & Varactor Diodes

Full-wave rectifier numerical + output waveform
OR

Working of tunnel diode and varactor diode with diagram

Q5 — BJT Biasing / Operational Amplifier Terms

Calculate VCEQ & ICQ for the BJT bias network (circuit given on Page 2)
OR

Definitions and explanation of Slew Rate, Virtual Ground, CMRR

Q7 — CRO Measurement / DSO

Measuring frequency, voltage, phase using CRO + Lissajous frequency calculation
OR

Block diagram of DSO (Digital Storage Oscilloscope) and comparison with analog CRO

These questions test deeper understanding of devices, measurements, waveforms, amplifier parameters, and oscilloscope operation.

OVERALL SUMMARY OF THE DOCUMENT

The Electronics Engineering (KOE038) exam paper evaluates core electronics topics:

Semiconductor behavior & breakdown

Zener regulator calculations

Rectifiers, waveforms, efficiencies

BJTs & biasing

FET characteristics

OP-AMP fundamentals (Slew rate, CMRR, virtual ground)

CRO measurement techniques & Lissajous figures

Tunnel diode & varactor diode

DSO working & comparison

The structure follows the AKTU format:

SECTION A: Quick conceptual recall

SECTION B: Detailed problems + theoretical explanation

SECTION C: Application-based and diagram-driven questions

The uploaded file consists of 3 pages, containing tables, diagrams, waveforms, and BJT circuit illustrations.