E E4811 Pages: 2
Reg No.: Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FOURTH SEMESTER B.TECH DEGREE EXAMINATION, APRIL 2018
Course Code: EE208
Course Name: MEASUREMENTS AND INSTRUMENTATION (EE)

Max. Marks: 100 Duration: 3 Hours
PART A
Answer all questions, each carries 5 marks Marks
1 Resistance of unknown resistance determined byWheatstone bridge given by ‏حب‎ (5)

110൩൦൦ limiting values of various resistances are 1८ 500Q + 1%, Ro
61562 1%. R3 = 100Q +0.5 %.Calculate:

i) Nominal value of unknown resistor

ii) Absolute error of unknown resistor in ohm,

iii) Limiting error in percentage of unknown resistor.

2 Classify resistances based on the range of measurement.With neat sketch (5)
describe the loss of charge method for the measurement of insulation resistance
of length of a cable.

3 Define the terms related to instrument transformer: (5)
i) Transformation ratio ii) Nominal Ratio iii) Burden.

4 Describe the method for determination of B-H curve of magneticmaterial (5)
usingstep-by step method.

5 With the help of diagram indicate the calibration of wattmeter using de (5)
potentiometer.

6 Describe bonded and unbonded strain gauge with their principle of operation. (5)

7 What isLissajous pattern? Clearly indicate the factors on which shape of these (5)
figures depends.

8 Compare temperature measurement using RTD and thermistors. (5)

PART B

Answer any two questions, each carries 10 marks

9 a) Draw the block diagram of a typical measurement system and indicate the (5)
functional elements in detail.

b) Describe the construction and working principle of single phase induction (5)
type energy meter.

10 a) Amoving coil ammeter has fixed shunt of 0.01Q.With a coil resistance of (5)
750Q and a voltage drop of 500mV across it, the full scale deflection is
obtained. (i) Calculate current through shunt. (ii) Calculate resistance of meter
to give full scale deflection if shunted current is 60A.

b) Give the construction and working principle of dynamometer type (5)
instrument. Also indicate the different errors in dynamometer type watt
meters.

11 2) With the help of neat sketch describe the method of measurement of earth (5)
resistance.

b) The coil of a moving coil voltmeter is 40 mm long and 30 mm wide and has 100 (5)
turns on it. The control spring exerts a torque a torque of 240x10°Nm when the
deflection is 100 divisions on full scale. If the flux density of magnetic field in
air-gap is 19/0/1723, Calculate the resistance that must be put in series with the coil
to give 1 V/division. The resistance of voltmeter coil may be neglected.

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