III/IV B.Tech Degree Examinations, April 2014
First Semester
Transducers
Time : 3 hours
Maximum Marks : 60
Answer question No.1 Compulsory
Answer ONE question from each Unit
1. Answer the following [12 x 1 = 12M]
a) What is active transducer? Give examples.
b) Name some examples of second order system.
c) Define random error with example.
d) Define gauge factor of strain gauge.
e) Mention the applications of LVDT.
f) What is force balance principle?
g) What are the materials used in K type thermocouple?
h) What are various applications of piezoelectric transducers?
i) What is the principle of bi metallic thermometer?
j) Draw the frequency response of piezoelectric transducers.
k) What is radiation pyrometer?
l) State law of intermediate metals of thermocouple.
UNIT - I [1 x 12 = 12M]
2. a) Define and explain the various dynamic characteristics of a instrumentation system.
2. b) Draw normal distribution curve of errors and hence define probable error. (OR)
3. a) Draw the generalized block diagram of measurement system and explain functions of each block.
3. b) Obtain the step response of first order system with suitable expression.
3. c) Certain measurement is repeated 10 times. The following values are obtained 5.11, 5.17, 5.03, 4.99, 5.15, 4.95, 5.13, 5.20, 4.92 and 5.01. Compute the mean, standard deviation and probable error.
UNIT - II [1 x 12 = 12M]
4. a) Derive an expression for gauge factor of strain gauges.
4. b) Explain in detail about bonded and unbonded strain gauges. (OR)
5. a) Mention the advantages, disadvantages and applications of LVDT.
5. b) Explain in detail about construction and working principle of thermistor.
UNIT - III [1 x 12 = 12M]
6. a) With a neat diagram, explain the principle and operation of electrostatic pressure transducer.
6. b) A barium titanate pickup has dimensions of 10 mm x 10 mm x 2.5 mm force acting on it is 5 N. The charge sensitivity of crystal is 100 PC/N. its permittivity is 12.5 x 10^{-9} F/m. Its modulus of elasticity is 12 x 10^{6}N/m^{2}. Calculate strain charge and voltage generated. (OR)
7. a) Discuss about electro dynamic acceleration transducer with neat diagram.
7. b) What is piezoelectric effect? Compare various piezoelectric materials? Derive expression for voltage sensitivity & charge sensitivity of piezoelectric crystal.
UNIT - IV [1 x 12 = 12M]
8. a) What is seebeck effect? Give an account of laws of thermocouple with their application.
8. b) Describe the working of optical pyrometer with neat sketch. (OR)
9. a) What are various types of thermocouples? Give the materials and temperature ranges of various types.
9. b) Explain the working of total radiation pyrometer with neat sketch.