Fourth Semester B.Tech. Degree Examination, December 2009
(2003 Scheme)
03-404 : ELECTRICAL MEASUREMENTS – I (E)
Time : 3 Hours Max. Marks : 100
PART – A
Answer all questions. Each question carries 4 marks.
1. What are the three general classes of error ?
2. Why do you need a battery in an ohm meter ?
3. Compare the performance of induction type watt meter with that of a electrodynamic
type.
4. Explain what is meant by the phase angle error of a wattmeter.
5. What are the precautions to be taken in using headphone as a detector ?
6. Describe the principal differences between the null and the equal deflection
measurement technique.
7. What are primary, secondary and tertiary measurements ? Explain with examples.
8. What type bridge is best suited for measurement of a) high Q and b) low Q
component ?
9. What are the limitations of Wheatstone bridge and how are they overcome in Kelvin
double bridge for small resistance ?
10. A voltmeter is calibrated to read from 100V to 200V. Its accuracy is specified with
in ?? 2%. Find the maximum error. (10×4=40 Marks)
PART – B
Answer any one question from each Module. Each question carries 20 marks.
MODULE – I
11. a) Describe the working of a PMMC instrument. As applied to this instrument
describe the terms : i) Over damped ii) Under damped and iii) Critically
damped. 12
b) A basic dc ammeter circuit uses a PMMC meter movement of 1 mA, 100??
internal resistance and an external shunt of 0.001??. What is the range of current
the circuit can be measured ? 8
12. a) Explain the construction of an analog multimeter. 12
b) What are the common sources of error occurring in electrical measuring
instruments ? 8
MODULE – II
13. a) Describe how you can calibrate an ammeter with the help of the potentiometer ? 10
b) Discuss the method of increasing the range sensitivity of dc potentiometer. 10
14. a) Discuss in detail the types of errors that may be encountered while measuring
power by means of an electro dynamic wattmeter. 10
b) Explain the one method of 3 phase power measurement. 10
MODULE – III
15. a) Derive the balance condition of Anderson bridge for measurement of inductance
of a coil. Draw its vector diagram. 10
b) What is Maxwells bridge ? Describe its working. Where do we use such bridge ? 10
16. a) The quality factor Q of a coil is ?? 10. Suggest a bridge to measure the values of
inductor and its series resistance. 10
b) How can you measure the unknown value of applied frequency using the above
bridge ? 10
––––––––––––––––
(2003 Scheme)
03-404 : ELECTRICAL MEASUREMENTS – I (E)
Time : 3 Hours Max. Marks : 100
PART – A
Answer all questions. Each question carries 4 marks.
1. What are the three general classes of error ?
2. Why do you need a battery in an ohm meter ?
3. Compare the performance of induction type watt meter with that of a electrodynamic
type.
4. Explain what is meant by the phase angle error of a wattmeter.
5. What are the precautions to be taken in using headphone as a detector ?
6. Describe the principal differences between the null and the equal deflection
measurement technique.
7. What are primary, secondary and tertiary measurements ? Explain with examples.
8. What type bridge is best suited for measurement of a) high Q and b) low Q
component ?
9. What are the limitations of Wheatstone bridge and how are they overcome in Kelvin
double bridge for small resistance ?
10. A voltmeter is calibrated to read from 100V to 200V. Its accuracy is specified with
in ?? 2%. Find the maximum error. (10×4=40 Marks)
PART – B
Answer any one question from each Module. Each question carries 20 marks.
MODULE – I
11. a) Describe the working of a PMMC instrument. As applied to this instrument
describe the terms : i) Over damped ii) Under damped and iii) Critically
damped. 12
b) A basic dc ammeter circuit uses a PMMC meter movement of 1 mA, 100??
internal resistance and an external shunt of 0.001??. What is the range of current
the circuit can be measured ? 8
12. a) Explain the construction of an analog multimeter. 12
b) What are the common sources of error occurring in electrical measuring
instruments ? 8
MODULE – II
13. a) Describe how you can calibrate an ammeter with the help of the potentiometer ? 10
b) Discuss the method of increasing the range sensitivity of dc potentiometer. 10
14. a) Discuss in detail the types of errors that may be encountered while measuring
power by means of an electro dynamic wattmeter. 10
b) Explain the one method of 3 phase power measurement. 10
MODULE – III
15. a) Derive the balance condition of Anderson bridge for measurement of inductance
of a coil. Draw its vector diagram. 10
b) What is Maxwells bridge ? Describe its working. Where do we use such bridge ? 10
16. a) The quality factor Q of a coil is ?? 10. Suggest a bridge to measure the values of
inductor and its series resistance. 10
b) How can you measure the unknown value of applied frequency using the above
bridge ? 10
––––––––––––––––
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