MEASUREMENTS AND INSTRUMENTATION - Model Question Paper

[ganeshbala]

EC1255-MEASUREMENTS ANDINSTRUMENTAION

(Regulation 2004)

Time:3hrs Maximum:100marks

Answer ALL questions.

PART A -  (10X2=20 marks)

1.What are the different types of standard of measurement?

2.What is a transfer instrument?

3.How is the electron beam focused to a fine spot on the face of the cathode ray tube?

4.List the disadvantages of storage cathode ray tube.

5.Give the functions of an attenuator in a signal generator.

6.What are the draw backs of tuned circuit analyzers?

7.What is the importance of gate time in frequency counter?

8.How is trigger time error reduced?

9.Distinguish between analog and digital data acquisition systems.

10.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?

PART B - (16X5=80 marks)

11.(a)(i)With a neat diagram explain in detail the construction of PMMC instrument.(8 )

(ii)How do you measure large currents in PMMC instruments?(4)

(iii)What is Ayrton shunt?(4)

Or

(b)(i)Discuss in detail about Kelvin double bridge.(8 )

(ii)With a neat diagram explain in detail about Hay bridge.(8 )

12.(a)With a neat diagram explain in detail about

(i)Ramp type DVM(8 )

(ii)Successive approximation DVM.(8 )

Or

(b)With a neat block diagram explain in detail about vector impedance meter.(16)

13.(a)With a neat block diagram explain in detail about the frequency divider typer of signal generator with

frequency modulation.(16)

Or

(b)Explain:

(i)General purpose spectrum analyzer.(8 )

(ii)Phase locked circuit for the first local oscillator of spectrum analyzer.(8 )

14.(a)(i)What method can be used to increase the frequency range of frequency counter.(8 )

(ii)How can this be achieved without degrading the accuracy of the counter.(8 )

Or

(b)Discuss in detail about

(i)Gating error

(ii)Time-base error and trigger level error.

(iii)Maximum accuracy achieved for frequency measurements.

15.(a)(i)What are the requirements of an automatic test system?

(ii)Explain in detail about IEEE 488 system.

Or

(b)With a neat block diagram explain

(i)Optical power meter

(ii)Auto ranging power meter

(iii)Optical time-domain reflectometer.

[ganeshbala]

MODEL QUESTION PAPER

B.E. Electrical and Electronics Engineering

Fifth Semester

EE331 – Measurement & Instrumentation

Time : 3 Hours Max Marks : 100

PART – A
Answer All Question (10 x 2 = 20 marks)

1. Define limiting errors? Derive the expression for relative limiting error?
2. Define linear time invariant and line time variant systems. Give examples.
3. Why PMMC ammeters are the most widely used instrument?
4. Draw the equivalent circuit and phasor diagram of a potential transformer.
5. List out the types of input circuits used in the signal conditioning.
6. Define (i) Differential mode gain (ii) Common mode rejection ratio.
7. Give the advantages and disadvantages of LCDS.
8. List out the basic components of a tape recorder.
9. An accelerometer has a seismic mass of 0.05kg and a spring constant of 3x103N/M. Maximum mass displacement is ±0.02m. Calculate.
(i) Maximum measurable acceleration (ii) Natural frequency
10. List out the advantages and disadvantages of RTD.

PART – B
(5 x 16 = 80 Marks)

11.i) A set of independent ten measurement were made to determine the weight of a load shot. The weights in gramme were 1.570, 1.597, 1.591, 1.562, 1.577, 1.580, 1.564, 1.586, 1.550, 1.575.
Determine
(i) Arithmetic mean
(ii) Average deviation
(iii) Standard deviation
(iv) Variance
(v) Proable error of one reading
(vi) Proable error of the mean

ii) A measuring system has an exponential response to step input. The time constant of the system is 2S. What is the time required for reaching (i) 50% and (ii) 80% of final steady state reading.

12.a) Explain in detail the effect of
(i) Opening the secondary circuit of a current transformer when primary winding is energized?
(ii) With a neat sketch explain the working of a 3F wattmeter.

OR

12.b)i) Explain the construction and working of Weston type frequency meter.

ii) Design a multirange ammeter with range of 1A, 5A, 25A and 125A employing individual shunts in each case. A d' Arsonval movement with an internal resistance of 730? and full-scale current of 5mA is available.

13.a)i) Explain in detail the successive approximation method of A/D Conversation.
ii) Explain the operation of V/F converter.

OR

13.b)i) A thermistor of resistance 1000? at 50°C temp is connected in a bridge circuit having all arms of resistance 1000?. The supply voltage to the bridge is 40V. The resistance of the thermistor increases by 5? for a decrease of temp of 1°C. Find the temp if the open circuit voltage of the bridge is 50mv.

ii) Explain the operation of sample and hold circuit with suitable diagram.

14.a)i) Draw the block diagram of a digital CRO and explain each block.
ii) The gap of reproducing head in a tape recorder is 6.4 µm. Determine the minimum speed of the tape for satisfactory response at 50KHZ.
Assume the wave length on the tap is greater than 2.5 times the gap length.

OR

14.b) Explain in detail the operation of any two digital printers.

15.a) Write short note on
i. Digital transducer
ii. Piezo electric transducer

OR

15.b)i) Explain the liquid level measurement using resistive method.

ii) Describe the method of measurement of differential pressure using inductive transducer.

[Mahesh Gowda]

Dear Sir,

Please forward me the answers for model question paper

Regards,

Mahesh Gowda