B.Sc. (Three Year) DEGREE EXAMINATION, MARCH/APRIL 2017.
End Semester Examination
Second Semester
Part II Electronics
ELECTRONIC DEVICES AND CIRCUITS
2 C 2312 A
Time 3 Hours Max. Marks 70
PART — A
Answer any FIVE of the following questions. 4 20 Marks)
1. Explain barrier potential of a P-N junction.
2. Discuss voltage-divider bias method.
3. Explain two transistor representation of SCR.
4. What are opto-isolators?
5. Explain the working of choke input filter.
6. Explain transistor as a switch.
7. Explain the working of photo diode.
8. Explain the list of 79XX voltage regulator.
PART — B
Answer ALL the following questions. 10 50 Marks)
9. Explain the construction and working of tunnel diode with V-I
characteristics.
Or
Explain the operation of zener-diode and its V-I characteristics. Give one
application of Zener diode.
10. Explain and analyse the hybrid equivalent circuit of CE transistor.
Or
Explain the input and output characteristics of common base configuration.

11. Explain the construction and working of JFET with the help of drain and
transfer characteristics.
Or
Explain the construction and working of UJT with V-I characteristics.
12. Explain the construction and working of a photo transistor.
Or
Explain IR emitters with a neat circuit diagram.
13. Explain the working of bridge rectifier and derive expression for ripple factor
and efficiency.
Or
Discuss Switch Mode Power Supply (SMPS).