Anna University Chennai 2005 B.E INSTRUMENTATION & MEASUREMENT - Question Paper

Code: A - 12 Subject: INSTRUMENTATION & MEASUREMENT
Time: three Hours Max. Marks: 100
NOTE: There are 11 ques. in all.
ques. one is compulsory and carries 16 marks. ans to Q. 1. must be written in the space given for it in the ans book supplied and nowhere else.
ans any 3 ques. every from Part I and Part II. every of these ques. carries 14 marks.
Any needed data not explicitly given, may be suitably presumed and said.
Q.1 Choose the accurate or best option in the following: (2x8)

a. The LVDT is primarily used for the measurement of
(A) displacement. (B) velocity.
(C) acceleration. (D) humidity.



b. The gauge factor of a bonded - wire strain gauge is approximately
(A) 4. (B) 3.
(C) 2. (D) 1.


c. The bridge used for measurement of high - Q inductors is
(A) Maxwell's bridge. (B) Schering's bridge.
(C) Hay's bridge. (D) Wien's bridge.


d. The material widely used for the production of electric potential by means of stress is
(A) Platinum. (B) Gold.
(C) Silver. (D) Quartz.

e. Digital instruments have an input impedance of the order of
(A) ohm. (B) mega ohm.
(C) kilo ohm. (D) milli - ohm.


f. Which of the subsequent analog to digital converters has a conversion time proportional to the analog voltage :
(A) counter kind (B) dual - slope integrator
(C) successive approximation (D) comparator type
g. In a CRT the focussing anode is located
(A) ranging from pre - accelerating and accelerating anodes.
(B) after accelerating anodes.
(C) before pre - accelerating anodes.
(D) ranging from horizontal deflection plates.

h. One of the subsequent is an active transducer
(A) strain gauge. (B) selsyn.
(C) photo - voltaic cell. (D) photo - emissive cell.

PART I
ans any 3 ques.. every ques. carries 14 marks.
Q.2 Explain the phenomenon of hysteresis in measurement systems. Also discuss the terms 'threshold', 'maximum input hysteresis', 'maximum output hysteresis', 'dead zone' and 'backlash'. Draw neat diagrams to discuss your ans. (14)

Q.3 Derive the dimensions of the subsequent volumes in LMTI system
(i) magnetic flux.
(ii) inductance.
(iii) capacitance
(iv) magnetic flux density. (14)

Q.4 Explain the working of a Q - meter. (14)

Q.5 Describe the working of an electronic D.C. voltmeter. (14)

Q.6 a. Describe the working of a C.R.O. (7)
b. Derive an expression for vertical deflection of an electron beam in Cathode Ray Tube. (7)
PART II
ans any 3 ques.. every ques. carries 14 marks.
Q.7 Draw the circuit diagram of a Kelvin's double bridge used for measurement of low resistance. Derive the condition for balance. (14)

Q.8 a. Describe the successive approximation method of analog to digital conversion. (7)

b. Describe 1 method of digital to analog conversion. (7)

Earning:   Approval pending.