About this previous year paper
ELECTRONIC MEASUREMENT & INSTRUMENTATION – B.Tech (SEM-IV), REC-403
This is a 3-hour, 70-mark theory examination designed to test a student's understanding of electronic measuring instruments, bridges, oscilloscopes, error analysis, PMMC, calibration systems, and digital meters.
The paper is divided into three major sections—short concepts (A), descriptive answers (B), and advanced numerical/diagram-based questions (C).
SECTION A — Short Conceptual Questions (2 × 7 = 14 Marks)
This section contains seven short, direct questions, checking fundamental definitions and basic understanding.
Topics include:
Primary & secondary standards Dissipation factor
Voltmeter loading & emitter follower Kelvin double bridge vs Wheatstone bridge
Absolute error calculation Essential components of CRT
Instrument calibration
These test basic theory, definitions, and measurement fundamentals.
SECTION B — Medium-Length Descriptive Questions (7 × 3 = 21 Marks)
Attempt any 3 out of 5 questions.
These require explanations, derivations, block diagrams, and understanding of instrument construction.
Topics include:
(a) PMMC Instrument
Construction
Proof of linear scale
(b) FET Input Voltmeter
Circuit diagram
Range-changing operation
(c) Maxwell Bridge
Derivation of formulas for unknown R & L
(d) Automatic Time Base of Oscilloscope
Block diagram
Waveforms at each stage
(e) X–Y Recorder
Working
Applications
These questions focus on instrument design, AC/DC bridges, and oscilloscope functionality.
SECTION C — Long/Analytical Questions (7 marks each)
Each question has two alternatives (a or b).
These require numerical solving, detailed derivations, instrument setup explanations, or block diagrams.
Q3 — Errors / Swamping Resistance
(a) Systematic errors + temperature-dependent resistor specification calculation
OR
(b) Swamping resistance concept, materials & PMMC voltmeter conversion numerical
Q4 — DMM / Dual-Slope Integrator
(a) Digital Multimeter
Resolution of 4½ digit DMM
Display of 16.58 on 10V range
OR
(b) Dual-slope integrator
Block diagram
Waveforms
Zero-crossing detector
Q5 — Resistance Measurement Methods
(a) Measuring resistance using ammeter–voltmeter
Two connections
Equations & error discussion
OR
(b) Kelvin Bridge
Circuit diagram
Operation
Derivation for unknown resistance
Q6 — Probes / Oscilloscopes
(a)
Attenuator probe
1:1 probe (with diagrams)
OR
(b)
DSO (Digital Storage Oscilloscope)
Comparison with Sampling Oscilloscope
Q7 — Chart Recorder / Wattmeter Calibration
(a) Pen-type galvanometer strip-chart recorder
Construction
Operation
OR
(b) Calibration importance
Circuit to calibrate wattmeter
Procedure explained
These questions test instrument calibration, measurement accuracy, oscilloscope analysis, and bridge-based measurement techniques.
OVERALL PURPOSE OF THE EXAM
This question paper evaluates if the student can:
Understand working principles of PMMC, DMM, DSO, bridges & voltmeters
Perform error analysis & understand systematic errors
Use AC/DC bridges to find unknown components
Interpret and explain oscilloscope time-base systems
Understand probe types and their importance
Use chart recorders & calibration circuits
Solve numerical problems involving resistance measurement & PMMC conversion
Understand construction & applications of measuring instruments
It covers both fundamental theory and practical instrumentation techniques, essential for electronics & instrumentation engineering.