Electronic Instruments and Measurements - Dec 2011

Electronics Engineering (Semester 3)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Explain multi-range ohm-meter with diagram(5 marks) 1 (b) What is back emf? Explain significance of back emf(5 marks) 1 (c) Explain the function of delay line in oscilloscope. Which are the two types of delay lines?(5 marks) 1 (d) State the requirements of a good laboratory type of signal generator(5 marks) 2 (a) Draw and explain FET as a voltmeter. What are its sensitivity considerations?(10 marks) 2 (b) Explain flash type ADC with suitable diagrams(10 marks) 3 (a) Explain digital phase flip flop. Write its advantages and disadvantages(10 marks) 3 (b) Explain the construction and working principle of Weston type frequency meter(10 marks) 4 (a) Explai beat frequency oscillator and its advantages(10 marks) 4 (b) Explain analog storage oscilloscope. State the drawbacks of analog storage oscilloscope.(10 marks) 5 (a) How will you find the value of capacitance with the help of schering bridge? Explain with the help of derivation and vector diagram(10 marks) 5 (b) Explain the construction and working of electrodynamometer type power factor meter.(10 marks) 6 (a) Explain different methods of speed control of dc series motors.(10 marks) 6 (b) Derive the torque equation for 3 phase induction motors. Explain v/f method of speed control of induction motors(10 marks)

Write short note on (any two) :-

7 (a) Megger(7 marks) 7 (b) Variable reluctance stepper motor(7 marks) 7 (c) Derivation of torque equation for moving iron meters(7 marks) 7 (d) Gear wheel method in CRO(7 marks)