Sensors and Industrial Instrumentation: notes and questions
For AEIE students
Notes for each topic, a formula sheet, practice questions and 41 past GATE questions from 7 papers (2018–2026), 41 of them solved step by step.
- previous-year questions
- 41previous-year questions
- solved step by step
- 41solved step by step
- GATE papers, 2018–2026
- 7GATE papers, 2018–2026
- topics with notes
- 7topics with notes
Foundation
Learn the subject one topic at a time. Each topic has notes, the key formulas and practice questions.
Topic notes and formulas
Notes on every topic, with the key formulas and practice.
Sensing principles and signal conditioning
This topic covers how resistive, capacitive, inductive, piezoelectric, electromagnetic and Hall sensors turn a physical quantity into an electrical one, and the circuits (bridges, instrumentation amplifier, charge amplifier) that make that signal usable.
5 practice questions
Displacement, velocity, acceleration, force, torque and vibration
This topic covers the transducers that turn motion and mechanical loading (displacement, velocity, acceleration, force, torque, vibration and shock) into electrical signals.
5 practice questions
Pressure and flow measurement
Pressure and flow measurement covers how a process pressure is sensed (liquid columns, elastic elements, low- and high-pressure gauges) and how volumetric flow is inferred from differential pressure, float position, induced emf, ultrasonic timing or turbine speed.
6 practice questions
Temperature measurement
Temperature measurement covers contact sensors (thermocouples, RTDs, thermistors, semiconductor sensors) and non-contact ones (pyrometers, bolometers), each with its own law, range and error sources.
5 practice questions
Level, pH, conductivity and viscosity
This topic covers four process measurements: liquid level (hydrostatic head, bubbler, displacer, float, capacitive, ultrasonic and radar), pH (glass electrode and the Nernst slope), conductivity (cell constant, AC excitation and temperature compensation) and viscosity (capillary, falling-sphere, rotational and efflux types).
5 practice questions
Instrument networks and the 4-20 mA transmitter
The 4-20 mA two-wire current loop carries a measured value as a current that is the same at every point of the series loop.
5 practice questions
Optical sources, detectors, interferometry and spectroscopy
This topic covers the optical devices behind many industrial measurements: LED and laser sources, photodiode, LDR and square-law detectors, Michelson-type interferometers and their use in metrology, fibre-optic sensing, NIR and UV-Vis analysis, and the mass spectrometer.
6 practice questions
Sensors and Industrial Instrumentation formulas by topic
GATE
Past GATE questions on Sensors and Industrial Instrumentation by topic and year, the full papers, practice and the GATE syllabus.
41 questions, by topic and year
How many questions each topic had in the IN papers of each year. This shows what was asked, not what will be asked. We placed each question under a topic ourselves; the exam paper does not label topics.
| Topic | 2018 | 2020 | 2022 | 2023 | 2024 | 2025 | 2026 | Total |
|---|---|---|---|---|---|---|---|---|
| Sensing principles | 2 | 3 | 1 | 4 | 2 | 4 | 3 | 19 |
| Motion & force | · | 1 | · | · | · | 1 | · | 2 |
| Pressure & flow | 1 | · | · | 1 | · | · | · | 2 |
| Temperature | 1 | · | 1 | · | · | 1 | 2 | 5 |
| Level & analytical | · | · | · | · | · | · | 1 | 1 |
| 4-20 mA & networks | · | · | · | · | 1 | · | · | 1 |
| Optical | 2 | · | 3 | 2 | · | 1 | 3 | 11 |
37 practice questions
The GATE syllabus for Sensors and Industrial Instrumentation, paper by paper
Verbatim from the GATE 2027 syllabus PDF: IN Section 9, “Sensors and Industrial Instrumentation”, and the rest of IN Section 10 — instrument and sensor networks, the 4–20 mA transmitter and optical instrumentation (its modulation and communication part is filed under Communications). Only IN lists sensors and transducers.
Show the GATE IN wordingHide the GATE IN wording
Resistive, capacitive, inductive, piezoelectric, electromagnetic and Hall effect sensors and associated signal conditioning circuits; transducers for industrial instrumentation: displacement, velocity, acceleration (linear and angular), force, torque, vibration, shock, pressure (including low and high pressure), flow (variable head, variable area, electromagnetic, ultrasonic, turbine flowmeters), temperature (thermocouple, bolometer, 2, 3, 4 wire RTD, thermistor, pyrometer and semiconductor sensor), liquid level, pH, conductivity and viscosity measurement. … instrument and sensor networks, 4–20 mA two-wire transmitter. Optical sources and detectors: LED, laser, photo-diode, light dependent resistor, square law detectors and their characteristics; interferometer: applications in metrology; basics of fiber optic sensing. Near- infrared (NIR) sensing, Ultraviolet-Visible (UV-VIS) spectrophotometers, mass spectrometer.
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