R05221001-calibration-and-electronic-measurements

Set No. 1

Code No: R05221001

II B.Tech Supplimentary Examinations, Aug/Sep 2008 CALIBRATION AND ELECTRONIC MEASUREMENTS (Electronics & Instrumentation Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write short notes on any of the F OU R: (a) (b) (c) (d) (e)

Arithmetic mean Deviation from the mean Average deviation Standard deviation Variance.

[16]

2. (a) Write short notes on atomic standards for frequency and time? (b) State the SI units, unit symbols and define each unit for the following: i. Voltage ii. Resistance iii. Inductance iv. Capacitance. [8+8] 3. (a) Explain the following terms: i. Accuracy ii. Bias iii. Calibration iv. Calibration interval. (b) SCALE READING PRECISION VOLTAGE 100 103 90 93 80 82.5 70 72.5 60 62 50 51.7 40 41.5 30 31 20 19.7 10 9.5 0 0

CORRECTION +3 +3 +2.5 +2.5 +2 +1.7 +1.5 +1 -0.3 -0.5 0

For the 20 and 60 readings in the calibration chart shown above determine the instrument accuracy as a percentage of the reading and as a percentage of full scale? [8+8] 1 of 2

Set No. 1

Code No: R05221001

4. (a) A dual slope integrating type A/D converter has an integrating capacitor of 0.1µf and a resistance of 100 KΩ. If the reference voltage is 2V and output of an integrating is not to exceed 10V what is the max time the reference voltage can be integrated? (b) Explain RF type of ammeter and give its limitation?

[8+8]

5. (a) Explain how a Kelvin’s double bridge can accurately measure low resistances. Also derive the condition for balance. (b) In the Kelvin’s Bridge shown in figure 5b the ratio of Ra to Rb is 2000Ω,R1 is 10Ω and R1=0.2 R2. Calculate the value of Rx . [10+6]

Figure 5b 6. (a) Draw the block diagram of a frequency counter used for the measurement of period. Explain its operation? (b) What are the different types of extending frequency range of a frequency counter? [3+5+8] 7. (a) Give the standard specifications of horizontal amplifier used in a single beam CRO (b) Explain the spot wheel method for frequency measurement.

[8+8]

8. (a) Draw and discuss the spectral displays of various modulations using spectrum analyzer. (b) Explain the F M method of magnetic tape recording and explain its advantages and disadvantages. [8+6+2] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05221001

II B.Tech Supplimentary Examinations, Aug/Sep 2008 CALIBRATION AND ELECTRONIC MEASUREMENTS (Electronics & Instrumentation Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) The table below gives the set of 10 measurements that were recorded in the laboratory. Calculate the precision of the 6th measurement? Measurement number 1 2 3 4 5 6 7 8 9 10

Measurement Value Xn 98 101 102 97 101 100 103 98 106 99

(b) Explain the following terms : i. ii. iii. iv.

Absolute error %Error Precision % of accuracy.

[8+8]

2. (a) Explain the concept of capacitance standards? (b) Define the seven base units of SI system?

[8+8]

3. (a) Write short notes on the concept of instrument calibration chain? (b) What is reliability and explain the concept of measurement reliability? [8+8] 4. Draw the block diagram of multimeters and explain its operation?

[16]

5. (a) Discuss the ”Direct-connection” technique of using Q-meter. (b) A coil with a resistance of 5Ω is connected to the terminals of the basic Qmeter. Resonance occurs at an oscillator frequency of 4 MHz and resonating capacitance of 80 pF . Calculate the percentage of error introduced by the insertion resistance ,Rsh=0.01Ω. [8+8] 6. (a) Differentiate between absorption and transmission type wave meters. item With a neat sketch explain the operation of frequency selective wave analyzer. [8+8] 1 of 2

Set No. 2

Code No: R05221001 7. (a) Explain the operation of 10 to 1 probe .

(b) A given oscilloscope has an input resistance of 10 M ohm shunted by 20 pf. Design a 10 to 1 probe. [8+8] 8. (a) Explain the operation of logic timing analyzer and logic state analyzer. (b) What are the merits and demerits of Magnetic recording? ⋆⋆⋆⋆⋆

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[5+5+6]

Set No. 3

Code No: R05221001

II B.Tech Supplimentary Examinations, Aug/Sep 2008 CALIBRATION AND ELECTRONIC MEASUREMENTS (Electronics & Instrumentation Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Draw the block diagram of the measuring system and explain the each stage with their functions? [16] 2. (a) Distinguish between International and absolute standards. (b) What are the international standards of length and volume? (c) Write short notes on concept of inductance standards?

[4+4+8]

3. What are the different types of calibrations used and explain each of them? [16] 4. (a) With a neat block diagram explain the potentiometric DVM? (b) AC basic D’Arsonal movement with a full scale deflection of 50 µA and internal resistance of 500Ω is used as a voltmeter. Determine the value of the multiplier resistance needed to measure the voltage range of 0-1V. [12+4] 5. (a) Explain the “parallel-connection” method of using Q-meter and Obtain the expressions for resistance , reactance and Q factor. (b) Give the list of the detectors used in ac bridges.

[10+6]

6. (a) Explain the operation of direct frequency synthesizer? What are its advantages and limitations? (b) Distinguish between time and phase measurements.

[8+2+6]

7. (a) Describe the electrostatic focusing system of a CRT. (b) What is the minimum distance L, that will allow full deflection of 4 cm at the oscilloscope screen with a deflection factor of 100 V/cm and with an accelerating potential of 2000 V ? [8+8] 8. (a) With a schematic diagram explain the operation of pulse duration modulation(PDM) recording system. (b) Draw the block diagram of a logic analyzer and explain its operation. [8+2+6] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: R05221001

II B.Tech Supplimentary Examinations, Aug/Sep 2008 CALIBRATION AND ELECTRONIC MEASUREMENTS (Electronics & Instrumentation Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Draw the block diagram of the measuring system and explain the each stage with their functions? [16] 2. Write short notes on any of the THREE: (a) International standards (b) Primary standards (c) Secondary standards (d) Working standards.

[16]

3. Write short notes on any of the T HREE : (a) Error calibration curve (b) Direct calibration (c) Indirect calibration (d) Routine calibration

[16]

4. (a) AC basic D’Arsonal movement with a full scale deflection of 50µA and internal resistance of 500Ω is used as a voltmeter. Determine the value of the multiplier resistance needed to measure the voltage range of 0-10V? (b) Explain the performance characteristics of DVM’s?

[8+8]

5. (a) Derive an expression for balance in an Anderson’s bridge. Draw the phasor diagram under balance conditions. (b) List the advantages and disadvantages of Anderson?s bridge.

[10+6]

6. Describe with the help of a circuit diagram, the working mechanism of a universal time counter. Explain the various functions it is capable of performing. [4+4+8] 7. (a) Name the various types of probes with their applications (b) Write short notes on time base generators used in oscilloscopes

[8+8]

8. (a) Compare the FFT analyzer with the super heterodyne spectrum analyzer. (b) Explain the F M method of magnetic tape recording and explain its advantages and disadvantages. [8+6+2] ⋆⋆⋆⋆⋆

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