(SEM IV) THEORY EXAMINATION 2017-18 ELECTRONIC MEASUREMENT & INSTRUMENTATION

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.