This is the B.Tech Semester III examination paper for Electronics Engineering (KOE038) carrying 100 marks, designed to assess a student's understanding of the fundamental principles of semiconductor devices, diodes, transistors, operational amplifiers, and measuring instruments. The exam duration is 3 hours, and the paper is divided into three structured sections: A, B, and C.
SECTION A – Short Answer Questions (20 Marks)
This section includes 10 questions of 2 marks each, covering essential theory topics:
Doping and its purpose
Why silicon is preferred over germanium
Clipper vs clamper circuits
LED vs photodiode
BJT vs FET differences
Threshold voltage of MOSFET & IDSS of JFET
Unity gain amplifier (buffer)
Slew rate in op-amps
Analog vs digital instruments
Applications of Cathode Ray Oscilloscope (CRO)
These questions check basic conceptual knowledge of semiconductor and measurement fundamentals.
SECTION B – Descriptive / Analytical Questions (30 Marks)
Students must attempt any three out of five questions. These questions require explanation, circuit diagrams, and conceptual clarity:
Avalanche and Zener breakdown mechanisms
Tunnel diode and varactor diode
Common-base BJT structure, working, input & output characteristics
Operational amplifier block diagram, ideal characteristics, op-amp as an adder
Digital Storage Oscilloscope (DSO) block diagram and comparison with analog oscilloscope
This section tests analytical understanding, device physics, and circuit-level interpretation.
SECTION C – Long, Application-Based Questions (50 Marks)
Students must attempt one part from each question. This section contains numerical problems, circuit analysis, and device design:
Q3 – Diodes (10 Marks)
VI characteristics of ideal vs practical diode + diode equation
OR diode resistances + variation of transition & diffusion capacitances
Q4 – Zener Networks / Waveform Analysis (10 Marks)
Find IZ, IL, IR, VL of a Zener diode network (diagram on page 2)
OR determine output waveform from given diode-resistor circuit
Q5 – MOSFETs / BJTs (10 Marks)
Enhancement vs depletion MOSFETs, cross-section, transfer characteristics
OR NPN transistor construction, α & β, and their relationship
Q6 – Op-Amp Applications (10 Marks)
Virtual ground concept and op-amp differentiator
OR analyze output of given op-amp circuits (page 2–3)
Q7 – Instruments (10 Marks)
Measurement of voltage, frequency, and phase using CRO
OR working of Digital Multimeter with block diagram
This section evaluates problem-solving, device operation depth, waveform interpretation, and instrumentation knowledge.
OVERALL SUMMARY
The Electronics Engineering KOE038 question paper covers:
Semiconductor physics (doping, diode behavior)
Special diodes (Zener, tunnel, varactor)
BJTs & FETs operation
MOSFET characteristics
Operational amplifiers (adder, differentiator, buffer, slew rate)
CRO, DSO, digital multimeter
Circuit analysis (Zener regulator, waveforms, op-amp circuits)
It is a comprehensive exam aimed at evaluating theoretical knowledge, circuit understanding, analytical skills, and practical electronics fundamentals required for core engineering subjects.
