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8/3/2019 BigQuestions&TwoMarks
http://slidepdf.com/reader/full/bigquestionstwomarks 1/11
MEASUREMENTS AND INSTRUMENTATION
PART B
UNIT 1: Measurement Concepts & Indicating Equipments
1. a. With a neat diagram explain in detail the construction of a PMMC
instruments.
b. How do you measure large currents in PMMC instruments?
c. What is Aryton shunt?
2. Discuss in detail about Kelvin double bridge.
3. With a neat diagram explain in detail about Hay Bridge.
4. With a neat block diagram explain in detail about vector impedance meter
5. Explain the types of error possible in an instrument and also discuss their
causes and remedies.
6. A resistance is measured by voltmeter ammeter method. Ammeter shows3.22A on a 10A scale and the voltmeter shows 96.6 V on accurate within ±0.5%
of full scale regarding. Find the indicated value of resistance and the limiting
error within which you can guarantee the result.
7. Explain how Schering Bridge is used for the measurement of unknown
capacitor. Derive its balance equation.
8. Explain, how the quality factor can be obtained using Schering Bridge?
9. With a neat diagram explain in detail about
Ramp type DVM and
Successive approximation DVM.10. With a neat block diagram explain in detail about vector impedance meter.
11. Explain how the Q-meter can be used for the measurement of Q factor and
effective resistance and discuss the sources of error.
12.A coil with a resistance of 10Ω is connected in the direct measurement mode.
Resonance occurs when the oscillation frequency is 10MHz and the resonating
capacitor is at 65PF. Calculate the % error introduced in the calculated value of
Q by the 0.02Ω insertion resistance.
13. Explain on the static and dynamic characteristics of a measurement system
14. If a set of six observations are as follows:
1.5V, 3V, 1V, 5V, 2V. Calculate the arithmetic mean, average deviation and
standard deviation.
15. Derive the bridge balance condition for the Maxwell Bridge and Schering
Bridge.
16. Find the equivalent parallel resistance and capacitance that causes a wein
bridge to null if the following components are given:
R1 = 8KΩ, C1 = 6µF
R2 = 30KΩ, f = 2.5 kHz
R3 = 1kΩ
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17. Discuss briefly on types of instrument errors and instrument faults. With neat
figure explain the need of WAGNER’S EARTH (ground) connection in bridge
circuit.
18. Briefly describe about different measurement methods. State the sources of
error in measurement and their remedial measures.19. State the importance of calibration of measuring instruments. Define standards
and classify them.
20. Draw the circuit diagram and phasor diagram for Schering Bridge. Drive the
expression for unknown capacitance.
21. With neat schematic explain the working of electronic weighing system.
22. Explain the working principle of moving coil instrument and derive an expression
for it s deflection and give its errors. How can the range of instruments be
extended?
22. A moving coil instrument has a resistance of 100Ω and gives a full scale
deflection with a full scale deflection with a current 50mA. This is converted to an
ammeter range 1000A. Find the shunt deflection.
23. Explain the working of a Schering bridge and how it is used to measure power
factor and dissipation factor of series RC combination.
24. Which ac bridge is used to measure frequency and explain the measurement
procedure? List the applications for AC Bridge.
25. With circuit diagrams explain working of electronic millimeter, the resistance
range selector circuit and commercially available VOM.
26. How is phase angle and magnitude of a component measured using vector
impedance meter?
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UNIT 3: Function Generator & Analyzers
1. With a neat block diagram explain in detail about the frequency divider type of signal generator with frequency modulation.
2. Explain:
i) General purpose spectrum analyzer.ii) Phase locked circuit for the first local oscillator of a spectrum analyzer.
3. What method can be used to increase the frequency of frequency counter?4. How can this be achieved without degrading the accuracy of the counter?5. Discuss in detail about
i) Gating error ii)Time base error and trigger level error iii)Maximum accuracy achieved for frequency measurements.
6. Draw and explain the block diagram of digital storage oscilloscope and themodes of operation of digital storage oscilloscope.
7. What are Lissajous patterns? How are they used for frequency
measurement?8. Draw and explain the block diagram of sweep generator covering entire
frequency band9. What is marker generator? How does it overcome the disadvantages of a
sweep generator?10.With a neat diagram describe the operation of a superhetrodyne spectrum
analyzer.11.What is the dynamic range of a spectrum analyzer with a third order intercept
point of +25db and a noise level of -85db?12.With a block schematic, explain the frequency mode and the frequency ratio
mode operation of a frequency counter.
13.What is meant by gating error in a frequency counter? How does it arise? Canit be eliminated?
14.Write briefly on the various torqueses in analog indicating instruments.15.With neat figures explain how frequency of a signal is measured using a CRO.16.With neat figures explain the construction and working principle of a digital
storage Oscilloscope. Compare its advantages over an analog CRO.17. Draw the block diagram of a AM/FM signal generator and explain its working.18. Briefly discuss about wave analyzers.19. With the block diagram explain the working of distortion analyzer.20. Explain the functioning of spectrum analyzer with neat diagram.
21.Ramp type DVM uses a 1MHz clock generator and a ramp voltage thatincreases from 0V to 12.5 in a time of 125ms. Determine the no of clockpulses counted into the register when Vi =0.9V and when it is 7.5V.
22.Draw waveforms to show how time period and a pulse width is measured on adigital frequency meter explain each case.
23. Draw the circuit diagram for time interval measurement and discuss itsoperation.
24. What is reciprocal counting? Where it is used?25. With neat block diagram explain the working of a digital storage oscilloscope.26. Briefly discuss about linear interpolation and sine wave interpolation.
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UNIT 4: Transducers
1. Write briefly on thermocouples and thermistors as temperature transducers.
2. With neat figure explain LVDT for velocity measurement.3. Name four types of electrical pressure transducer and describe one application of
each type.
4. Under what conditions is a dummy strain gage used and what is the function of
that gage?
5. What is the difference between a photoemissive, a photoconductive and a
photovoltaic cell? Name one application for each cell.
6. What is a transducer? Briefly describe any one of the displacement transducers.7. Explain the transduction principle used in the capacitor microphone.8. Explain in detail the working of a Linear Variable Differential Transformer.
9. Explain the use of LDR in the field of light measurement.10. Discuss with suitable diagrams the salient features of unbounded and bonded
strain gauges.11. Explain the principle of operation of a resistance thermometer.12. Explain passive transducer.
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UNIT 5: Modern Measurement Techniques
1. What are the requirements of an automatic test system?
2. Explain in detail about IEEE 488 system.
3. With a neat block diagram explain
i) Optical power meter
ii)Auto ranging power meter iii)Optical time domain reflectometer.
4. With a neat schematic, explain the operation of a dual slope analog to digital
conversion
5. A dual slope ADC uses a 16 bit counter and 4 MHz clock rate. The maximum
input voltage is +10V. The maximum integrator output voltage should be -8V
when the counter has cycled through 2^n counts. The capacitor used in the
integrator is 0.1µF. Find the value of the resistor R of the integrator.
6. Explain the generalized block schematic of a Digital Data Acquisition system
and list out its advantages over analog Data Acquisition system.7. What are the various techniques of multiplexing ? Discuss any one in detail?
8. Draw the schematic diagram of a computer –controlled measurement system for
testing a radio receiver using an automatic system
9. Explain the various management lines and data byte transfer lines of GPIB
10. Write briefly on any TWO:
i) Dot matrix display
ii) Advantage and principle of LCD Displays
iii)Digital data logger
11. How are A/D converters classified? With neat diagram explain the construction
and principle of successive approximation type ADC.
12. Write briefly on thermocouples and thermistors as temperature transducers.
13. With neat figure explain LVDT for velocity measurement.
14.Draw a block diagram to show how high frequency wave form can be sampled
to create a low frequency dot representation of wave form bring out the
relationship between the signal frequency, the dot waveform frequency and no of
samples per cycle in low frequency wave.
15.Briefly discuss the operation of digital recorders and state the relative
advantages of digital recorders over analog recorders.
16.With neat block diagram explain the functioning of computer controlled testingof radio receiver.
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17.State the salient features of GPIB instrument.
18.Draw the schematic of IEEE 488 instrumentation bus and explain its features.
19.Write a brief note on instruments used in computer controlled instrumentation
20.With a neat block diagram discuss the working of dual slope integration type
ADC and the measurement of voltage from the same. List the advantages.21.Why I it required to evaluate sensitivity and resolution of the digitizer?
22. Discuss the measurement of the following with necessary diagrams:
i) Totalizing and period mode ii) Time interval and time interval averaging.
23.Describe the principle of a bus system to communicate between instruments
and explain the configuration of IEEE 488 bus in detail.
24. With a block diagrams explain optical power meter and how can it be
modified to display logarithmic power?
25.Explain automatic test system to analyze an audio amplifier with a block
diagram.
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Part –A
UNIT 1: Measurement Concepts & Indicating Equipments
1. Precision is a necessary but not sufficient condition for accuracy. True or
False. Justify your answer.
2. What are the two conditions to be satisfied to make an AC bridge balanced?
3. What is a vector voltmeter?
4. What are the different types of standard of measurement?5. What is a transfer instrument?
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6. How is trigger time error reduced?
7. Give the principle of operation and need for Q-meter.
8. Define static errors and how are they classified.
9. What is difference between analog and digital instruments?
10.What is the importance of dynamic characteristic of systems?11.Why must instruments be calibrate?
12.What are the advantages of digital instruments over analog instruments?
13.How resistors and diodes are checked using digital multimeters?
14.Bring out the differences between DC and AC Bridges
15.Draw the circuit diagram for frequency modulation using variable voltage
capacitor (VVC) diode. State the specific purpose of using VVC diode
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UNIT 3: Function Generator & Analyzers
1. Justify – ‘A CRO can be regarded as a X-Y recorder’.
2. What are the requirements of signal generator?
3. What is real time spectrum analyzer?
4. Enumerate the advantages of digital meter over the analog meter
5. Why is period mode preferred for measurement of very low frequency in a
frequency counter?
6. How is the electron beam focused to a fine spot on the face of the cathode ray
tube?
7. List the disadvantages of storage cathode ray tube
8. Give the functions of an attenuator in a signal generator 9. What are the drawbacks of tuned circuits analyzers?
10.What is the importance of gate time in frequency counter?
11.The current in a circuit is got by using a resistance R of 3 Ω. The vertical trace
of the CRO screen is 10cm and the Y amplifier setting is 6V/cm. Find the rms
value of current taking the waveforms as a sine wave.
12.How is voltage converted to frequency in V-F conversion?
13.How much loss will be experienced if a fiber of numerical aperture of 0.3 is the
source for a fiber with a numerical aperture of 0.242?
14.What is the dynamic range of a spectrum analyzer with a third order interceptpoint of +25dBm and a noise level of 85dB?
15.Derive the condition for sustained oscillation in feedback oscillators.
16.What is electromagnetic interference in instruments?
17.Write briefly in pink plotter.
18.Explain briefly on magnetic tapes.
19.How is frequency, amplitude and pulse width changed in a pulse generator?
20.A frequency counter with an accuracy of ± 1LSD ±(1×10^-6) is employed to
measure frequencies 100 Hz, 1MHz, and 100 MHz. Calculate the percentage
measurement error in each case
21.What is a power scope? Bring out the differences compared with ordinary
CRO.
22.What is a self balancing potentiometer? Where it is used?
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UNIT 4: Transducers
1. What are active and passive transducers? Why are they called so?2. What are the basic requirements of a transducer?3. What is LDR?4. What is a transducer?5. What is photovoltaic effect?6. What is meant by gauge factor of a strain gauge?7. What is a thermocouple?8. How is a thermocouple used for temperature measurement?9. State the name of electrical transducer used for temperature measurement.10.Give the application of strain gauge.
11.Give examples of electrical transducer.12.Write the application of displacement transducer.13.Define gauge factor of a strain gauge.14.Define Transducers. Bring the advantages of electric transducers.15.How are strain gauge used for pressure measurement?
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UNIT 5: Modern Measurement Techniques
1. What is meant by IEEE 488 standard and GPIB?
2. What are the various instruments used in computer controlled instrumentation
system?
3. Distinguish between analog and digital data acquisition systems.
4. How much elapsed time would occur to a reflection from a break in an optical
fibre of 1.4km if the index of refraction of the core was 1.55?
5. List the requirements of ADC in voltmeters and millimeters.
6. Write briefly on serial interfacing.
7. Why is a fixed attenuator inserted between a piston attenuator and the
oscillator of a signal generator?
8. What is meant by quantization error?
9. State any four advantages of Digital Instruments over analog Instruments.
10.Name the different instruments required to completely test an Audio amplifier
with the help of computer. Show their connection diagram.
11.Define interface functions and device functions.