# Dr.A.P.J.Abdul Kalam University BE III SEM ALL BRANCH DEC 2020 Electrical Measurements and Instrumentation [EX-221] Dec - 2020 Question Paper

Dr.A.P.J.Abdul Kalam University Old Question Papers

Bachelor of Engineering

Third Semester Main Examination, Dec-2020

Electrical Measurements and Instrumentation [EX-221]

Branch: EX

Time: 3:00 Hrs Max Marks 70

Note : 1. Attempt any five questions out of eight.

2. All questions carry equal marks.

Q.1 (a) Define the terms:

(i) Accuracy (ii) Precision

(iii) Static sensitivity (iv) Reliability

(b) What do you mean by calibration curve? Explain loading effects due to shunt connected and

series connected instruments.

Q.2 (a) Explain the construction and working of D’arsonal Galvanometer.

(b) Expalin why PMMC instruments are the most widely used instruments. Discuss their

Q.3 (a) Explain with the help of block diagram the working of Digital voltmeter.

(b) Write down the difference between current transformer and potential transformer. Also

explain their working.

Q.4 (a) Describe the constructional details and working of an electrodynamometer type of

wattmeter. Discuss the main sources of errors in electrodynamometer type instruments

(b) Explain the measurement of power using:

(i) Three wattmeter method

(ii) CTs and PTs

Q.5 (a) Explain the construction and operation of single phase and three phase electronic energy

meter.

(b) What is Phantom loading? Explain with example. Also describe the testing by phantom

Q.6 (a) Describe the circuit diagram of a series type ohm meter. Explain how is it designed. Why are

series type ohm meter preferred over shunt type ohm meters?

(b) What is a B-H curve in terms of magnetic material? Write down its characteristics?

Q.7 Write short notes on (any two):

(a) Lloyd fisher square method

(b) Economics of measurement system

(c) Kelvin’s double bridge

(d) Maximum demand meter

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