Download SGBAU BSc 2019 Summer 3rd Sem Electronics Devices n Circuits Question Paper

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B.Sc. Part-II (Semester-III) Examination

ELECTRONICS

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(Electronics Devices and Circuits)

Time : Three Hours] [Maximum Marks : 80

Note :— (1) Question No. 1 is compulsory.

(2) Draw neat diagrams wherever necessary.

1. (A) Fill in the blanks with correct word : 2
   1. In ideal Op-Amp value of input impedance is __________

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   2. Bistable multivibrator has __________ stable states.
   3. D/A is known as __________
   4. Voltage gain of Non-inverting amplifier is __________
2. (B) Choose the correct alternative : 2
   1. In ideal Op-Amp bandwidth is :
      1. Zero

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      2. Minimum
      3. Infinite
      4. None
   2. The monostable multivibrator has __________ stable state(s).
      1. 2

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      2. 1
      3. 3
      4. 4
   3. One of the following is not an oscillator :
      1. Colpitts

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      2. Wein bridge
      3. Push pull
      4. Hartley
   4. Op-Amp IC 741 has total __________ pins.
      1. 2

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      2. 6
      3. 14
      4. 8

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3. (C) Answer the following questions in ONE sentence : 4
   1. What is feedback ?
   2. List the hybrid parameters.
   3. Define CMRR.
   4. What is oscillator ?

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EITHER

2. (A) Give the advantages and disadvantages of direct coupled amplifier. 4
3. (B) Draw hybrid equivalent circuit for CE transistor amplifier and derive the expression for
   1. Current gain
   2. Input impedance for CE-transistor amplifier. 8

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OR

1. (P) Explain the working of single tuned amplifier with circuit diagram.
2. (Q) State the advantages and disadvantages of RC coupled amplifier. 4

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3. (A) Explain the construction and working of Class B push pull amplifier. Find its efficiency. 8

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4. (B) Explain cross over distortion. How it is eliminated ? 4

OR

1. (P) Draw a circuit diagram of transformer coupled Class A amplifier and derive expression for its efficiency. 8
2. (Q) Give the classification of amplifiers. 4

EITHER

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4. (A) Explain Barkhausen criterion for sustained oscillations. 4
5. (B) Explain the construction and working of Hartley oscillator. 8

OR

1. (P) Explain the construction and operation of RC-phase shift oscillator using transistor. State its advantages. 8
2. (Q) State the advantages of negative feedback. 4

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EITHER

5. (A) Explain the working of Op-Amp as non-inverting amplifier and derive the expression for voltage gain. 6
6. (B) With suitable diagram explain the working of Op-Amp as summing amplifier. 6

OR

1. (P) Explain the concept of virtual ground in Op-Amp. 4

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2. (Q) Define :
   1. Common mode voltage gain
   2. Differential mode voltage gain.
3. (R) Draw the block diagram of Op-Amp and explain the function of each block. 6

EITHER

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6. (A) Explain the construction and working of Op-Amp as a monostable multivibrator. 6
7. (B) Explain how Op-Amp is used as damped harmonic oscillator. 6

OR

1. (P) Explain the working of Op-Amp as a Schmitt Trigger. 6
2. (Q) Explain the working of Op-Amp as an astable multivibrator. 6

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EITHER

7. (A) Explain the working of successive approximation type A/D converter. 8
8. (B) Explain the terms
   1. D/A Accuracy
   2. D/A Resolution. 4

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OR

1. (P) Describe the construction and working of Weighted Resistor type D/A Converter. 6
2. (Q) Explain the need of D/A and A/D converter. 4
3. (R) What is A/D and D/A converter ?

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