# QUESTION PAPER 2

a) What is rectifier? With a neat sketch, explain the working of bridge rectifier. 5

b) Draw and explain the V-I characteristics of a pn junction. 5

a) A full wave rectifier uses two diodes, the internal resistance of each diode may be

assumed constant at 20 Ω The transformer r.m.s. secondary voltage from centre tap to each

end of secondary is 50 V and load resistance is 980 Ω Find :

b) What is zener diode? Explain how zener diode maintains constant voltage across the load.                                                                                                                                        5

a) Draw and explain the input and output characteristics of CE configuration. 5

b) Define α and β. Show that . 5

4.A transistor is connected in CE configuration in which collector supply is 8V and

the voltage drop across resistance  connected in the collector circuit is 0.5V.

The value of  If α=0.96, determine:

collector-emitter voltage ii.         base current                             10

Write short note on:                                                                                                        10

LASER diode  ii.  Transducer and its application

a) In a CB connection, α=0.95. The voltage drop across 2 Kresistance which is connected is 2V.Find the base current.                                                                                                4

b) Draw and explain the constructional diagram of cathode ray oscilloscope.             6

a) Explain the operation of tank circuit with neat diagrams. 6

b) In a certain RC oscillator circuit the value of R=220 k and C=250 pF. Determine

the frequency of oscillations.                                                                                        4

a) Explain the term calibration, accuracy and precision.             5

b) What are the different methods of measurement of flow.                                               5

a) What are the functions of filter circuit?  Explain capacitor filter with a neat circuit diagram and  waveforms      (4 Marks)

b) The four diodes used in abridge rectifier circuit have forward resistance which may be considered at 1 Ω and infinite reverse resistance.  The alternating supply voltage is 240 V r.m.s. and load resistance is 480 Ω calculate mean load current and power dissipated in each diode.                                                  (6 Marks)

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