About this previous year paper
This document contains the B.Tech (Semester I) Theory Examination 2024–25 for the subject Fundamentals of Electronics Engineering (BEC101).
The paper is designed to evaluate a student’s foundational understanding of basic electronic devices, digital electronics, analog circuits, logic design, modulation techniques, operational amplifiers, and semiconductor behavior.
The paper is divided into three main sections (A, B, and C), gradually progressing from basic conceptual questions to detailed analytical and numerical problems.
SECTION A – Short Answer Questions (Basic Concepts & Definitions)
Section A consists of 7 brief questions (2 marks each), designed to test conceptual clarity and basic understanding.
The questions cover:
1. Semiconductor Physics
Why depletion region reduces in forward bias
Negative resistance behavior in a tunnel diode
2. FETs and Operational Amplifiers
Why FETs are unipolar and voltage-controlled
Ideal characteristics of an op-amp
3. Digital Logic
Why NAND and NOR gates are universal gates
Binary arithmetic operations
4. Communication Systems
Calculation of modulated wave power for AM
This section evaluates K1–K3 cognitive levels and basic problem-solving ability.
SECTION B – Descriptive Questions (Application-Based Understanding)
Students must attempt any 3 out of 5 questions, each carrying 7 marks.
These questions involve explanation, derivation, and numerical analysis.
Topics include:
1. Zener Diode Current Calculation
Understanding maximum and minimum current limits in regulated circuits.
2. Common Collector Configuration
Why CC mode is not preferred
Calculation of dynamic output resistance
3. Op-Amp Circuits
Output voltage determination for a given op-amp circuit
Op-amp integrator operation and output derivation
4. Amplitude Modulated Wave
Finding minimum & maximum amplitude
Identifying frequency components and their magnitudes
This section tests K3–K4 levels: analytical thinking, interpretation of circuits, and detailed explanation.
SECTION C – Long Answer Questions (Advanced Concepts & Numerical Design)
This is the most comprehensive part of the paper. Students must attempt one part from each numbered question (3, 4, 5, 6, 7).
Questions require calculations, derivations, circuit analysis, Boolean minimization, and design understanding.
3. Rectifiers / Clipper Circuits
3(a) Half-wave rectifier using transformer (10:1)
Calculate DC output voltage
Calculate peak inverse voltage (PIV)
3(b) Negative clipper circuits
Advantages
Determine peak value of output waveform
4. MOSFETs / BJT Common Base Calculations
4(a) Why enhancement MOSFET is preferred over depletion MOSFET
4(b) Common base configuration
Base current calculation using given values
5. Operational Amplifiers
5(a) Derive that op-amp output is proportional to difference of input voltages (difference amplifier)
5(b) Calculate output for a given op-amp circuit
6. K-Map Simplification / POS Minimization
6(a) Simplify Boolean function using K-map and design logic circuit
6(b) Minimize Boolean function in POS form using 5-variable K-map
These questions test digital logic design skills.
7. Communication Systems (Amplitude Modulation)
7(a) AM wave with:
Carrier frequency: 1 MHz
Modulating frequency: 5 kHz
Modulation index: 50%
Calculate:
Lower & upper sideband frequencies
Sideband amplitudes
7(b) Derive:
Transmission efficiency
Total power of an AM wave (assuming sinusoidal signals)
This part evaluates knowledge of analog modulation, sidebands, bandwidth, and power distribution.
Summary of Topics Covered
This question paper comprehensively assesses the student’s understanding of:
Semiconductor diodes & their characteristics
Transistor configurations (BJT, FET, MOSFET)
Zener diode regulation
Operational amplifiers (integrator, difference amplifier)
Digital logic gates, Boolean algebra, K-map simplification
Binary arithmetic operations
Rectifier circuits, clipper circuits
AM modulation: sidebands, power, bandwidth
Basic circuit calculations: currents, voltages, resistances
It integrates both theory and practical circuit analysis, ensuring students can apply electronics fundamentals to real-world engineering problems.