Mumbai University Previous year question papers
IV Sem Electronics Examination June 2010
Electronic and Electrical Measuring Instruments and Machine
N.S. : (1) Question NO.1 is compulsory.
(2) Attempt any four questions out of remaining six questions.
(3) Assume suitable data wherever required and state clearly.
(4) Figures to the right indicate full marks.
1. Answer any four of the following :-
(a) What are the advantages of electronic voltmeter over the other voltmeters?
(b) State the advantages, disadvantages and errors in PMMC instrument?
(c) Expain the applications and the limitations of the wheatstone bridge.
(d) Explain the working principle of DC motor.
(e) Explain the method of Lissajous patterns used for the frequency measurement.
2.(a) Explain the R/2R ladder technique of D to A conversion.
(b) Explain the various performance parameters of digital voltmeter.
3.(a) Explain the digital frequency meter with neat diagram. 10
(b) Explain digital phase meter using flip/flop. Write its advantages and disadvantages.
4. (a) Explain beat frequency oscillator and its advantages.
(b) Draw and explain the block diagram of digital storage oscilloscope.
5. (a) An energy meter is designed to make 100 revolutions of the disc for one unit of energy. Calculate the no of revolutions made by it when connected to a load carrying 20 A, at 230 V, at 0,8 p.t. for an hour. If it makes 360 revolutions actually, find the % error.
(b) Derive the torque equation for moving iron instruments. 10
6. (a) Which measurements can be carried out by Maxwell bridge? Derive the balance equation and expressions for the unknown components.
(b) Explain the operating principle of 3-phase induction motor. 10
7 Write short note on any three of the following :-
(a) Stepper motor
(c) FET Voltmeters
(d) Use of CRO in component testing.