MEASUREMENTS & INSTRUMENTATION Questions Bank 2014

Anna University, Chennai

M.A.M SCHOOL OF ENGINEERING, SIRUGANUR, TRICHY

SUBJECT: MEASUREMENTS & INSTRUMENTATION

SEMESTER : III YEAR: II QUESTION BANK UNIT- I FUNDAMENTALS

Part-A

1. Give the methods of obtaining experimental data.

2. List out the dynamic characteristics of any measurement system.

3. What are the types of errors in measurements?

4. What are the static characteristics of an instruments

5. What is a standard? What are the different types of standards?

6. What is the function of manipulation element in a measurement system?

7. What are the primary standards? Where are they used?

8. What is primary sensing element?

9. What is calibration?

10. Define arithmetic mean.

11. Define variance

12. Define standard deviation?

13. Define average deviation.

14. Define the terms precision and sensitivity

15. Define static error.

16. Distinguish re-productibility and repeatability.

17. Show the block diagram indicating functional elements of measurement systems.

18. Distinguish between zero drift and span drift.

19. Distinguish between steady state response and transient response.

20. Define dynamic response of an instrument.

21. What are the different calibration methodologies?

22. Define limiting errors.

23. Define median.

24. Mention any four static characteristics of measuring instruments.

25. Distinguish between the direct and indirect methods of measurements.

26. Define instrumental errors

27. What is the significance of calibration?

28. What is the importance of dynamic characteristic of system?

29. Why must instruments be calibrated?

30. What is meant by accuracy of an instrument?

31. Define international standard ohm.

32. What is the different between accuracy and precision?

33. List the different types of possible errors in measurements.

34. Define Environmental error.

35. Define static error and how is it classified.

36. What is the different between analog and digital instruments?

37. What is the need for measurement?

38. Write the need for calibration.

39. What are basic elements of a generalized measurement system?

40. What is meant by measurements?

PART-B

1. Draw the block diagram showing the basic functional

elements of an instrument and explain the functions each.

2. Define limiting errors. Derive the expression for relative limiting error.

3. Define the following :

a) Arithmetic mean, b) Mean deviation, c) Median, d)

standard deviation. e) variance.

4. Briefly explain the different types of standards

5. Explain in detail the different types of errors in measuring instruments.

6. Explain in detail calibration technique and draw the calibration curve in General.

7. Give methods of using any three standard inputs being used for analysing the Dynamic response of system with neat sketches.

8. Why is feed back necessary in instrumentation systems?

9. Derive the expression for magnitude and phase of a first order system when subjected to a sinusoidal input signal. Draw the magnitude and phase verses frequency plots.

10. Explain on the static and dynamic characteristics of a measurement system.

11. What are the categories of systematic errors in the instrument and explain in Detail.

12 A voltmeter reads 112.68v,Is the true value of the voltage is

112.6v, determine the following: (1) The static error

(2) The static error correction for the voltmeter.

13. A wattmeter having a range of 500 w has an error of ±1.5 percent of full scale deflection. If the true power is 50w, what should be the range of readings? If the Error is specified as percentage of true value, what would be the range of the readings?

14. By using the micrometer screw the following readings were taken of a certain physical length:

1.31 , 1.38 , 1.56 , 1.47 , 1.42 , 1.44 , 1.53 , 1.48 , 1.40 , 1.59 mm. Assuming that only random errors are present, calculate the following:

(1) Arithmetic mean

(2) Average deviation

(3) Standard deviation

(4) Variance

15. A thermometer reads 92.35° C and the static correction Given in the correction curve is 0.07° C. Determine the true Value of the temperature.

16. Explain in detail the types of static error.

17. Define and explain the following: (1) Instrumentation error

(2) Limiting error ,

(3) Environmental error

18. Describe in detail the different types of dynamic errors in

A measurement system.

19. Define the following static characteristics of an instrument

(1) Accuracy, (2) Resolution , (3) Sensitivity , (4) Linearity

20. A pressure indicator showed a reading as 42 bar on a Scale range of 0-50 bar .If the true value was 41.4 bar, Determine (1) static correction, (2) relative static error.

UNIT-II ELECTRICAL AND ELECTRONICS INSTRUMENTS

PART-A

1. What is creeping in energy meters? How it is prevented?

2. What is the working principle of wattmeter employed in measuring equipment?

3. How are the analog instruments classified on the basis of method used for comparing the unknown quantity?

4. Give the advantages of moving iron meters?

5. What are the different methods of measurement of frequency in the power frequency range?

6. Explain why it is necessary to make the potential coil circuit purely resistive in wattmeters?

8. How the resistors are checked using digital multimeters?

9. What is auto ranging?

10. Define resolution of DVM?

11. What is volt ampere hours and watt-hour?

12. What is the need to evaluate phase – angle error in instrument transformers?

13. What is the purpose of instruments?

14. What are the various types of digital voltmeters?

15. How a PMMC meter can be used as voltmeter and ammeters?

16. What are the various principles of analog type electrical instruments?

17. Give the importance of iron loss measurements.

18. What is the reason for using MI instruments on both AC and

DC?

19. What is the precaution to be followed while using current transformers?

20. What is a transfer instruments?

21. Why PMMC instruments are not used for ac measurements?

22. Explain the principle of digital phase meter? Why?

23. Which torque is absent in energy meter? Why?

24. Explain the purpose of Schmitt trigger in digital frequency meter.

25. What is the principle of ramp type digital voltmeter?

26. What are the sources of error in dc voltmeter measurement?

27. What are the essential parts of a ramp type digital voltmeter?

28. Define nominal ratio of instrument transformers.

29. Explain the following term as applied to digital displays 3½

digit and 4½ digit display

30. Derive the torque equation of electrodynamometer type instrument.

31. What is AYRTON shunt?

32. What are the different methods used in high frequency measurement?

33. What are the functions of instrument transformers?

34. Draw the circuit of digital voltmeter.

35. Explain the various methods of magnetic measurements.

36. Write short notes on accuracy of digital meters.

37. Draw the schematic block diagram of digital multimeter.

39. What is the principle of current transformer?

40. What are methods of iron loss measurement?

PART-B

1. Explain with neat circuit diagram the working of successive approximation type DVM.

2. Draw the circuit diagram of digital phase meter and explain its working.

3. Give the construction and principle of operation of single phase induction type energy meters.

4. Describe the construction and function of mechanical type

(vibrating reed type) frequency meter.

5. Explain the functioning of Ferro-dynamic type electrical resonance frequency meter.

6. Describe the construction and working principle of PMMC

instruments.

7. Describe the step by step method for determination of B-H

curve of a magnetic material.

9. Write briefly with neat figures on the principle and operation of (a) current transformer,(b) B-H curve analysis of a magnetic circuit.

10. Explain the working of moving iron instruments.

11. With neat figures, explain the construction working principle of a three phase watt meter. What is the importance of deflecting torque in these analog instruments?

12. Explain the working of a digital multimeter with a schematic block diagram.

13. Explain with neat circuit diagram the working any one type of digital voltmeters.

14. Determine the minimum number of output bits required for an ADC to give a quantitizing error less than 0.5%.

15. Explain the working of a digital and analog phase meters.

With neat diagram.

16. Explain the functioning of integrating type.

17. With a neat diagram explain the various methods of magnetic measurements.

18. Give detailed notes on instruments.

19. How the range of dc ammeter and dc voltmeter can be extended. Derive the expressions to calculate shunt resistance and multiplier resistance.

20. Explain The Function And Working Of 3-Phase Energy

Meter And Wattmeter

UNIT-III COMPARISION METHODS OF MEASUREMENTS

PART-A

1. What is potentiometer?

2. Mention some advantages of potentiometer.

3. Mention some application of potentiometer?

4. What are the types of potentiometer?

5. What are the types of DC potentiometer?

6. Mention some practical applications of DC potentiometer.

7. What are the classifications of AC potentiometers?

8. What is the main difference in operation between DC

potentiometers and AC potentiometers?

9. What are the advantages of ac potentiometers?

10. What are the disadvantages of ac potentiometers?

11. Mention some applications of ac potentiometers.

12. What is a bridge circuit?

13. What are the uses of bridge circuits?

14. What are the advantages of bridge circuits?

15. What are the two main types of bridges?

16. What is a DC bridge?

17. What are types of DC bridges?

18. What is a wheat stone bridge?

19. Write the balancing equation for Wheatstone bridge.

20. What are the applications of Wheatstone bridge?

21. What is Kelvin Bridge?

22. Draw the circuit diagram of Kelvin’s bridge.

23. What is Kelvin Bridge?

24. Draw the circuit diagram of Kelvin double bridge.

25. Draw the basic circuit diagram of AC Bridge.

26. What are the conditions which must be satisfied for the AC Bridge?

27. What is Schering Bridge?

28. Draw the circuit diagram of Schering Bridge.

29. What are the advantages of Schering Bridge?

30. What is Maxwell Bridge?

31. Draw the circuit diagram of Maxwell Bridge.

Bridge?

33. What is Hay Bridge?

34. Draw the circuit diagram of Hay Bridge.

36. What is Owen Bridge and also draw the circuit diagram?

37. What is Anderson Bridge and draw the circuit diagram?

38. What is Wien bridge and draw the circuit diagram?

39. What is earth loop? What is electromagnetic interference?

40. What is transformer ratio bridge and its applications?

PART-B

1. What is electromagnetic interference in instruments?

Derive the condition for sustained oscillation in feed back oscillations.

2. Derive the bridge balance condition for the Maxwell

Bridge and Schering.

3. Discuss briefly on type of instruments errors and instruments faults. With neat figure explain the need Wagner’s earth (ground) connection in bridge circuit.

4. What are the active circuit and passive bridge circuits?

5. What are leakage current effects?

6. Discuss in detail (1) bridge to measure low-Q of a coil

(2) Cause and effects of poor grounding in instruments.

7. Explain in detail about the laboratory type DC potentiometer. And give the applications of AC potentiometers.

8. Describe about the multiple earth and earth loops. and different techniques of grounding.

9. Draw Maxwell’s ac bridge and give the balance equation in terms of resistance.

10. Describe the circuit of Kelvin double bridge used for measurements of low resistance. Derive the conditions for balance.

11. Explain in detail the measurements that are made in the following bridge circuits.(1) wheat stone bridge (2) deflection type bridge.

12. A Wheatstone bridge consists of the following parameter.

13 .Explain how the inductance is measured in terms of known capacitance using Maxwell’s bridge.

14 Explain the working of a Schering bridge and how it is used to measure power Factor and dissipation factor of series RC combination.

15 With neat diagram explain in detail about Hay Bridge.

16 Draw the circuit diagram and phasor diagram for Anderson

Bridge. Derive the expression for unknown inductance.

17 Find the equivalent parallel resistance and capacitance that causes a wien bridge to null with the following

18 Bring out the differences between DC and AC bridges.

19 What are the two conditions must be satisfied to make an ac bridge balance.

20 (A)Explain how the quality factor can be calculated using Schering Bridge. (B)Explain the method of measuring the insulating property of capacitor by relevant bridge circuit.

UNIT-4 STORAGE AND DISPLAY DEVICES PART-A

1. What are the advantages and disadvantages of FM method of magnetic tape recording?

2. What are the different types of amplifiers used for CRO’S?

3. Give the principle of LCD type display device.

4. Draw a neat diagram of X-Y recorder.

5. Write two advantages of LED on electronic displays.

6. What is the power requirement of LCD?

7. What are the advantages of magnetic tape recorder?

8. What is the isolation probe?

9. State the features of ink-jet printers.

10. Differentiate between LED and LCD.

11. What are the various methods of recording data?

12. In what ways line printers are advantageous over dot matrix printer?

13. What are the different types of magnetic recording?

14. What are the different materials used in LED? Also name the colours emitted?

15. What are data loggers?

16. What are the functions of data loggers?

17. What are the basic components of tape recorders?

19. What are the advantages of LCD over LED?

20. What are the sweepers in oscilloscope?

21. List out the controllers normally found in X-Y recorder.

22. What is the basic operating principle of digital tape recording?

recording?

24. Define the deflection sensitivity of CRT.

25. List out the main parts of cathode ray tube.

26. What is recorder?

27. What is magnetic recorder?

28. Draw the diagram of oscilloscope.

29. Write briefly on DOT matrix display.

30. What is the principle of LCD display?

31. Describe the principle of digital storage oscilloscope.

32. Describe the performance of digital plotter.

33. Draw The Block Diagram Of General Purpose Oscilloscope.

34. Give the basic block diagram of a digital data recording system.

35. Describe the basic components of CRT.

36. What is the various methods of magnetic recording.

37. Define the direct recording in magnetic tape recorder.

38. Define the FM (frequency modulation) recording.

39. Define the PDM (pulse duration modulation) recording.

40. Draw the block diagram of digital CRO.

PART-B

1. Explain the FM method of magnetic tape recording and explain its advantages and disadvantages.

2. Give the over view of different digital display devices

3. Describe the different parts of a CRT with a help of a neat diagram.

4. Describe the principle of working and circuit diagram of a digital

Oscilloscope.

5. With neat figure explain the construction and working principle of a digital Storage oscilloscope. Compare its advantages over an analog CRO.

6. Write briefly any two: (1)Dot matrix display,(2) Advantage and principle of LCD display. (3) Digital data logger.

7. Explain in detail with suitable diagram. (1) Magnetic tape

(2) Digital printers

8. Explain in detail, how the data is stored in a magnetic disk and tape?

9. Describe the performance of digital plotter.

10. Explain the block diagram of general purpose oscilloscope and also describe the observation of waveform a CRO.

11. Write notes on liquid crystal diodes (LCD)

12. Describe construction and working of LCDs, mention he difference between Light scattering and field effect types of LCDs, and also explain the advantages of LCDs.

13. What is an X-Y recorder? How do you distinguishing X-t from

Y-t recorders?

14. Describe the pulse duration modulation (PDM) as used in magnetic tape Recording and explain its merits and demerits.

15. Discuss in detail about the various types of recorders.

16. Discuss in detail about dot matrix displays.

17. Discuss in detail about the application of CRO.

18. Describe the basic components of CRT.

19. With a neat block diagram explain the working of digital storage oscilloscope.

20. Explain the block diagram of oscilloscope with a neat sketch.

UNIT-5 TRANSDUCERS AND DATA ACQUISITION SYSTEM

PART-A

1. Define transducer?

2. Mention some advantages of electrical transducers.

3. Mention some basic requirements of a transducer.

4. What are the classifications of transducer?

5. What is primary transducer?

6. What is secondary transducer?

7. What is an active transducer?

8. Mention some example for active transducer.

9. What is a passive transducer?

10. What is an analog transducer?

11. What is an digital transducer?

12. What is an inverse transducer?

13. Mention some importance selection of transducer.

14. What are the types of potentiometer?

16. Define strain gauge.

17. Define gauge factor.

18. Mention types of strain gauges.

20. What is resistance thermometer?

21. What are the requirements for the resistance materials used in RTDS?

23. What is thermistor?

25. Mention some application of thermistor.

26. What is an inductive transducer?

27. Mention some advantages of LVDT.

28. List out the disadvantages of LVDT.

29. Mention the applications of LVDT.

30. What is the basic principle of capacitive transducer?

32. What are the applications of capacitive transducer?

33. What are the materials used for piezoelectric transducer?

34. What are the modes of operation of piezoelectric crystals?

35. What are the types of DAS?

36. Mention some advantages of fibre optic sensor.

37. What are the essential functions of digital DAC?

38. What are the types of analog to digital converter?

39. What are the types of digital to analog converter?

40. What is smart sensor and application of smart sensor?

PART-B

1. How the transducers are classified on the basis of principle of operation?

2. What are the essential functional operations of a digital data acquisition system?

3. Explain how using a differential arrangement, a capacitive transducer which works on the principle of variation of capacitance with displacement between two plates, the response can be made linear.

4. Describe the different modes of operation of piezo electric transducers.

5. Explain the generalized diagram of a digital data acquisition system. and give the uses of data acquisition system.

6. Mention the importance of setting time in D/A converter.

7. Explain the term piezoelectric effect.

8. Describe in detail the successive approximation method of analog to digital conversion.

9. Describe the different principles of working of capacitive transducers.

10. Explain the construction and principle of working of a LVDT. Explain how the magnitude and direction of displacement of core of an LVDT detected.

11. How are strain gauge used for pressure measurement?

12. What is meant by quantization error and how are A/D

converters classified?

13. Write briefly on thermocouples and thermistors as temperature transducers.

14. With neat figure explain LVDT for velocity measurement.

15. With neat block diagram explain single and multichannel data acquisition system. Give example for each block.

16. Write short notes: (1) Integral type analog to digital converter. (2) Thermocouple.

17. Give the factors to be considered for selecting a transducer.

And why is an A/D converter usually considered as an encoder?

18. Discuss R-2R ladder type D/A converter.

19. Explain the resistive transducer with respective potentiometer. Define inverse transducer with respective potentiometer.

20. Explain the principle of piezoelectric transducers and name any two piezoelectric materials.