About this previous year paper
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.