Electronic Instrumentation - Jun 2015
Electronics & Communication (Semester 3)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Define the following with examples:
iv) Significant figures.(8 marks) 1 (b) With a schematic, explain a true RMS voltmeter.(6 marks) 1 (c) Calculate the value of the multiplier resistor for a 50V RMS ac range on the voltmeter as shown in Fig. Q1(c).
Give the working principle of following:
2 (a) (i) V-F type DVM(6 marks) 2 (a) (ii) Successive approximation.(6 marks) 2 (b) Explain the principle, construction and working of a digital frequency meter.(8 marks) 3 (a) Draw the basic block diagram of an oscilloscope and explain the functions of each block and mention the advantages of negative HV supply.(10 marks) 3 (b) Explain dual trace oscilloscope with a neat block diagram.(10 marks) 4 (a) Explain the need for a delayed time base oscilloscope. Draw the block diagram of a delayed time base, and explain how it operates.(10 marks) 4 (b) With block diagram, explain the operation of an analog storage oscilloscope.(10 marks) 5 (a) Explain the operation of conventional standard signal generator with the help of block diagram.(6 marks) 5 (b) Write a brief note on function generator.(4 marks) 5 (c) Explain the operation of a sweep frequency generator with the help of a suitable block diagram. Mention its applications.(10 marks) 6 (a) Explain the operation of the Maxwell's bridge, with a neat circuit diagram. Derive an expression for unknown values of resistance and inductance. What are the limitations of Maxwell's bridge?(10 marks) 6 (b) Explain the operation of the capacitance comparison bridge, with a neat circuit diagram and derive the necessary equations.(6 marks) 6 (c) A capacitance comparison bridge is used to measure a capacitance impedance at a frequency of 2kHz. The bridge constant at balance are C3=100μF, R1=10KΩ, R2=50KΩ, R3=100KΩ. Find the equivalent series circuit of the unknown impedance.(4 marks) 7 (a) List at least five advantages of electrical transducer.(5 marks) 7 (b) Explain the method of measuring displacement using LVDT with a suitable diagram. State the advantages and disadvantages of LVDT.(10 marks) 7 (c) Write a note on differential output transducers.(5 marks) 8 (a) Write a note on photo transistor.(5 marks) 8 (b) List at least five classifications of digital displays.(5 marks) 8 (c) Explain the operation of the measurement of power by means of bolometer bridge, with the suitable circuit.(10 marks)