UNIT BASED ONLINE EXTERNAL EXAMINATION - OCTOBER – 2020 - ANALOG ELECTRONICS - 7BPH5C1

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ALAGAPPA UNIVERSITY
KARAIKUDI – 630 003
UNIT BASED ONLINE EXTERNAL EXAMINATION - OCTOBER – 2020
FIFTH SEMESTER SLOT – I

ANALOG ELECTRONICS 7BPH5C1

Total Marks: 50                                                                                           Time: 2.0 Hrs

SECTION A - MCQ - 20 x 1 = 20 Marks

1. To turn an intrinsic semiconductor into a p-type extrinsic semiconductor which one of the following materials can be mixed with it?

A. Silicon                                                                     B. Diamond

C. Phosphorous                                                           D. Boron         

2. The forward resistance of a diode has the following order of magnitude value

A. 103 Ω                                                                       B. 106 Ω

C. 10 Ω                                                                         D. 105 Ω                                                          

3. The forward voltage drop of a silicon diode is around

A. 5 V                                                                          B. 7 V

C. 0.7 V                                                                        D. 100 V

4. What is the special property of a diode, which makes it very useful?

A. Conduction in both directions                                B. Conduction in the forward direction only

C. Its high resistance                                                     D. Zero resistance      

5. The diode is /a/an

A. Linear device                                                          B. Android device

C.  None of the other three choices                            D. Non-linear device  

6. The main application of a Zener diode is

A. Amplification                                                          B. Rectification

C. Voltage regulation                                                  D. Voltage multiplication       

7. The main disadvantage of a half wave rectifier is

A. It uses only one diode                                             B. Ripple factor is high

C. Requirement of diode with high power rating    D. It’s too simple

8. The maximum theoretical efficiency of a full wave rectifier is

A. 80.2 %                                                                     B. 81.2 %

C. 40.6 %                                                                     D. 33.3 %

9. Ripple factor of a half wave rectifier is

A. 1.21                                                                         B. 3.14

C. 2.12                                                                         D. 5.34

10. A capacitor blocks

A. AC                                                                           B. DC

C. Voltage                                                                    D. Current

11. BJT stands for

A. Bi Junction Tetrode                                                            B.  By Jitter Triode

C. Bipolar Junction Transistor                                              D. None of the others

12. The transistor transfers current flow from 

A. Low resistance side to high resistance side           B. Low resistance side to low resistance side

C. High resistance side to high resistance side          D. High resistance side to low resistance side

13. Number of PN junctions in a transistor is/are

A. 1                                                                              B. 2

C. 0                                                                              D. 4

14. The depletion region is devoid of

A. Ions                                                                        B.  Mobile charges

C. Protons                                                                  D. Neutrons

15. A BJT has following three parts

A. Emitter, Base and Collector                                    B.  Gate, Source and Drain

C. Anode, Cathode and Electrode                               D. Emitter, Drain and Gate

16. The Base-Emitter voltage drop is approximately [for silicon transistors]

A. 0.9 V                                                                       B. 1.2 V

C. 0.6 V                                                                       D. 3.4 V

17. The schematic symbol for a NPN transistor shows the emitter arrow

A. to come out                                                            B. to go in  

C. No arrow is drawn                                                D. to go in and out

18. The base of a PNP transistor is

A. a p-type extrinsic semiconductor                           B. intrinsic semiconductor 

C. a c-type semiconductor                                          D.  an n-type extrinsic semiconductor

19. Current gain (β) of a BJT [in CE mode] has a typical value of, around

A. 300                                                                          B. 10

C. 1000                                                                        D. 1

20. The base, emitter and collector currents in an NPN transistor obeys the equation

A. IC = IE + IB                                                              B.  IC = IE - IB  

C. IB = IE + IC                                                               D. IC = IE + IB  

SECTION B - DESCRIPTIVE - 5 x 6 = 30 Marks

ANSWER ANY FIVE

21. What are intrinsic and extrinsic semiconductors? How are they formed?

22. Describe the working of a bridge rectifier with neat circuit diagram.

23. Derive an expression for the efficiency of a half wave rectifier.

24. Explain the working of an RC filter. What are its’ disadvantages?

25. Explain the working of a Zener voltage regulator with neat diagrams.

26. Describe the characteristics of a transistor in CE mode.

27. Derive the relationship between α and β.

28. Explain the potential divider bias in detail.