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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.