About this previous year paper
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