(SEM IV) THEORY EXAMINATION 2024-25 SENSOR & INSTRUMENTATION

This document contains the complete B.Tech (Semester IV) Theory Examination 2024–25 question paper for Sensor & Instrumentation (BOE405). It spans two printed pages, carries 70 marks, and evaluates a student’s understanding of sensors, transducers, data acquisition systems, displacement/temperature/pressure measurements, ADC/DAC systems, smart sensors, graphical programming, and industrial automation applications.

Section A – Short Answer Questions (14 Marks)

Section A includes seven 2-mark questions (Page 1) covering fundamental concepts of sensing and instrumentation:

Definition and classification of sensors based on energy source

Role of RTD in temperature measurement

Difference between Weighted Resistor DAC and R–2R Ladder DAC

Principle of LVDT for displacement measurement

Role of timers in data acquisition systems

Concept of self-testing in smart sensors

Basic difference between sensors and transducers

These questions test core basics required for instrumentation engineering.
 

Section B – Analytical & Application-Based Questions (21 Marks)

Students attempt any three of the five 7-mark questions (Page 1). Topics include:

Piezoelectric Pressure Measurement

Explanation of pressure measurement using a piezoelectric sensor with diagram.

Laser Flow Sensors

Working principle and industrial applications of laser-based flow measurement.

ADC Sampling & Aliasing

Numerical problem on:

Quantization step size of a 12-bit ADC

Maximum measurable signal frequency without aliasing
(based on 1 kHz sampling & 10 V reference)

Successive Approximation ADC

Working principle with block diagram.

Smart Sensor Output Calculation

Given sensitivity and offset voltage, calculate output voltage at 50°C and discuss self-calibration.

Section B checks practical understanding and numerical problem-solving.
 

Section C – Long, High-Level Questions (35 Marks)

Section C contains 5 questions (Q3–Q7), each with two alternatives, requiring detailed explanation or diagrams.

Q3 – Pressure Measurement / Potentiometer Displacement Measurement

LVDT-based diaphragm pressure measurement with circuit diagram
OR

Working, principle & limitations of potentiometer for displacement sensing
(Page 2)

Q4 – Ultrasonic Flow Sensors / Capacitive Level Sensors

Operating principle and industrial applications of ultrasonic flow sensors
OR

Construction, advantages & limitations of capacitive level sensors

Q5 – Graphical Programming (LabVIEW-type)

Concepts of WHILE and FOR loops with examples
OR

Advantages of graphical programming in industrial automation

Q6 – DAC and Communication

Working of R-2R Ladder DAC with numerical example (3-bit)
OR

Role of data sockets in networked communication with block diagram

Q7 – Smart Sensors

Components and characteristics of smart sensors with neat diagram
OR

Role of self-communicating smart sensors in industrial automation with examples