University of Mumbai 2009-3rd Sem B.E Electrical and Electronics Engineering Basic Electronics - Question Paper

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Con. 2519-09.    (REVISED COURSE)     V264

(3 Hours)    [ Total Marks : 100

N.B. (1) Question No. 1 is compulsory.    ivi    

(2) Attempt any four questions out of remaining six questions.    H

1.    (a) Explain the operation of Zanier diode in the forward and reverse biased condition 10

and draw its characteristics.

(b) A 100 jaf capacitor when used as a filter has 12 V dc across it with a terminal 10 load resistor of 2.5 k ohm. If the rectifier is full wave and supply frequency is 50 Hz what is the percentage of ripple in the output ?

2.    (a) vWrite a notes on :    10

(i)    Thermal stabilization

(ii)    Compensation.

(b) Explain the working of a CE BJT voltage amplifier.    10

3.    (a) Draw the h-parameter model of a transistor CE amplifier and derive equation 10

for Av, Ri, Ro and Ai.

(b) Explain the effects of negative feedback on following :    10

(i)    Input impedance

(ii)    Voltage gain

(iii)    Output impedance

(iv)    Current gain.

4.    (a) Explain the construction, characteristics and working of a typical JFET used for 10

the voltage amplification.

(b) Explain the working of biasing circuit of JFET amplifier with resistive load which 10 will give stabilization of operating quiescent point against device variation. What will be the input impedance and output impedance for the amplifier ?

5.    (a) Explain the operation of a photo transistor with the help of suitable diagram. 10 (b) An amplifier with negative feedback gives an output of 12.5 V with an input of 10

1.5 V, when feedback is removed, it requires 0.25 V input for the same output.

Find

(i)    Value of voltage gain without feedback

(ii)    Value of p if the input and output are in phase and p is real.

6.    (a) Explain the AC analysis of dual input balanced output differential amplifier. 10 (b) Write a short notes on :    10

(i)    LED    (iii) Solar sell

(ii)    Photodiode    (iv) Optoisolators.

7.    (a) Explain the voltage doublers circuit with the help of suitable circuit diagram and 10

waveform.

(b) Write a short notes on any two :    10

(i)    Schottkey diode

(ii)    Varactor diode

(iii)    PIN diode.