05212201 C A L I B R A T I O N A N D E L E C T R O N I C M E A S U R E M E N T S
1. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 1
II B.Tech I Semester Supplimentary Examinations, November 2008
CALIBRATION AND ELECTRONIC MEASUREMENTS
(Instrumentation & Control Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. The following 10 observations were recorded when measuring a voltage: 41.7, 42.0,
41.8, 42.0, 42.1, 41.9, 42.0, 41.9, 42.5 and 41.8 volt Calculate
(a) the arithmetic mean
(b) the deviation from the mean
(c) the average deviations
(d) Standard deviation
(e) Variance
(f ) Probable error of one reading
(g) Probable error of mean
(h) Range
[16]
2. (a) State the SI units, unit symbols and de ne each unit for the following
i. Conductance
ii. Magnetic ux
iii. Flux density
iv. Inductance
(b) A bar magnet with a one inch square cross section is said to have a total
magnetic ux of 500 Maxwell. Determine the ux density in tesla? [8+8]
3. Write short notes on any of the :
(a) Testing
(b) Calibration
(c) Reliability
(d) Traceability [16]
4. (a) A 10mA meter movement with an internal resistance of 100 is to be converted
into a 0-100mA. Calculate the value of shunt resistance required?
(b) State di erent types of thermocouples and explain the e ect of frequency on
thermocouples? [12+4]
5. (a) Explain how a Kelvin’s double bridge can accurately measure low resistances.
Also derive the condition for balance.
1 of 2
www.studentyogi.com www.studentyogi.com
2. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 1
(b) In the Kelvin’s Bridge shown in gure 5b the ratio of Ra to Rb is 2000 ,R1
is 10 and R1=0.2 R2. Calculate the value of Rx . [10+6]
Figure 5b
6. (a) With a neat sketch explain the operation of a co-axial wave meter.
(b) What are various synthesis techniques which generate di erent frequencies
from a given reference frequency? [8+8]
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) Compare the selectivity characteristics of the spectrum analyzer and wave
analyzer.
(b) Explain the following terms associated with spectrum analyzer.
i. Sensitivity
ii. Dynamic Range
iii. Harmonic mixing [7+3+3+3]
2 of 2
www.studentyogi.com www.studentyogi.com
3. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 2
II B.Tech I Semester Supplimentary Examinations, November 2008
CALIBRATION AND ELECTRONIC MEASUREMENTS
(Instrumentation & Control Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. Write short notes on any of the :
(a) Gross errors
(b) Instrument errors
(c) Environmental errors
(d) Observational errors [16]
2. (a) Determine the dimensions of charge, power and voltage.
(b) Describe the international standard of length and volume? [12+4]
3. (a) Write short notes on the concept of traceability?
(b)
SCALE READING PRECISION VOLTAGE CORRECTION
100 103 +3
90 93 +3
80 82.5 +2.5
70 72.5 +2.5
60 62 +2
50 51.7 +1.7
40 41.5 +1.5
30 31 +1
20 19.7 -0.3
10 9.5 -0.5
0 0 0
For the 30 and 70 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]
4. Draw the block diagram of multimeters and explain its operation? [16]
5. (a) Find the series inductance, resistance and Q of an inductive element using
Maxwell bridge .Given Z1=parallel combination of a resistor of value 470
and a capacitor of value 0.5 F, Z2=Z3=2K . The bridge is driven by a 3
KHz sinusoidal source.
(b) Explain the principle and working of Q meter? [8+8]
6. (a) Distinguish between time and phase measurements?
1 of 2
www.studentyogi.com www.studentyogi.com
4. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 2
(b) Explain any two metho ds generally used to extend the frequency range of a
frequency counter? [6+5+5]
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 selectivity characteristics of the spectrum analyzer and wave
analyzer.
(b) Explain the following terms associated with spectrum analyzer.
i. Sensitivity
ii. Dynamic Range
iii. Harmonic mixing [7+3+3+3]
2 of 2
www.studentyogi.com www.studentyogi.com
5. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 3
II B.Tech I Semester Supplimentary Examinations, November 2008
CALIBRATION AND ELECTRONIC MEASUREMENTS
(Instrumentation & Control Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) Explain the following terms
i. Instrumental error
ii. Limiting error
iii. Random error
iv. Probable error
(b) The current passing through a resistor of 100 ± 0.2 is 2.00 ± 0.5A. Using
the relationship P = 2R, Calculate the limiting error in the computed value
of power dissipation? [8+8]
2. Write short notes on any of the THREE:
(a) International standards
(b) Primary standards
(c) Secondary standards
(d) Working standards [16]
3. (a) Explain the concept of traceability?
(b) Explain the concept of primary and secondary calibration? [8+8]
4. (a) Write short notes on the principle of RMS voltmeter?
(b) Explain with a neat block diagram dual slope type DVM? [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 gure 5b the ratio of Ra to Rb is 2000 ,R1
is 10 and R1=0.2 R2. Calculate the value of Rx . [10+6]
Figure 5b
1 of 2
www.studentyogi.com www.studentyogi.com
6. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 3
6. (a) When is period measurement preferred over frequency measurement and ob-
tain the condition ?
(b) With a suitable block diagram explain the operation of a pre scaled frequency
counter. [4+4+8]
7. (a) Describe the electrostatic focusing system of a CRT.
(b) What is the minimum distance L, that will allow full de ection of 4 cm at the
oscilloscope screen with a de ection factor of 100 V/cm and with an acceler-
ating potential of 2000 V ? [8+8]
8. (a) Explain the di erent applications of spectrum analyzer.
(b) Explain the F M recording method. [8+8]
2 of 2
www.studentyogi.com www.studentyogi.com
7. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 4
II B.Tech I Semester Supplimentary Examinations, November 2008
CALIBRATION AND ELECTRONIC MEASUREMENTS
(Instrumentation & Control Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) De ne the following terms:
i. Absolute error
ii. %Error
iii. Precision
iv. % of accuracy
(b) What are the four sources of possible errors in instruments and explain each
of them brie y? [8+8]
2. (a) Explain the concept of capacitance standards?
(b) De ne the seven base units of SI system? [8+8]
3. (a) What is reliability and explain the concept of measurement reliability?
(b) Explain the calibration of DC and AC instruments? [8+8]
4. (a) For the circuit shown ( gure 4a) calculate the AC and DC sensitivity?
Figure 4a
(b) Sketch a neat block diagram of microprocessor based ramp type DVM and
explain brie y? [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 gure 5b the ratio of Ra to Rb is 2000 ,R1
is 10 and R1=0.2 R2. Calculate the value of Rx . [10+6]
1 of 2
www.studentyogi.com www.studentyogi.com
8. www.studentyogi.com www.studentyogi.com
Code No: R05212201
Set No. 4
Figure 5b
6. (a) With the help of a block diagram explain the multiplexed display technique
used in a frequency counter.
(b) Explain in detail about frequency mo de errors and period mode errors. [4+6+6]
7. (a) Draw the block diagram of a catho de ray oscilloscope and describe the oper-
ation of each blo ck.
(b) Explain the method of nding phase, frequency relationship of two waveforms
using Lissa jous gures. [2+6+4+4]
8. (a) With a neat sketch explain the operation of a strip chart recorder.
(b) Explain di erent applications of spectrum analyzer. [2+6+8]
2 of 2
www.studentyogi.com www.studentyogi.com