(SEM I) THEORY EXAMINATION 2024-25 FUNDAMENTALS OF ELECTRONICS ENGINEERING

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.