Bangalore University Diploma Instrumentation & Control Engineering ELECTRONICS & COMMUNICATION ENGINEERING BOARD 2009 Question paper

II SEMESTER DIPLOMA EXAMINATION, MAY 2009
ELECTRONICS & COMMUNICATION ENGG. BOARD
FOR INSTRUMENTATION CONTROL ENGINEERING

SEMICONDUCTOR DEVICES

Time : 3 Hours Max. Marks : 100

Note : 1. Section - I is compulsory.

2. Answer any six full questions choosing two questions each
from Sections - II, III and IV.

SECTION - I

1. (a) Fill in the blanks :
(i) A FET is essentially a .......... driven device.
(ii) A semiconductor diode designed to operate in the break down region is called a ............ diode.
(iii) Schottkey diode has a ........... semiconductor junction.
(iv) LED emits light only when ............. biased.
(v) Out of three regions of a transistor ............ is more heavily doped than the other.
(b) Explain majority and minority carriers.

SECTION - II

2. (a) Explain conductor, insulator and semiconductor in terms of energy level diagram.
(b) What is dopent? List the types of dopents with examples.
(c) Explain the formation of PN junction.

3. (a) Explain the effect of temperature on barrier.
(b) Explain VI characteristics of semiconductor diode under forward and reversed bias.
(c) With the basic construction features explain the working of Gunn diode.

4. (a) Explain the following terms :
(i) Reverse breakdown voltage.
(ii) Peak Inverse voltage.
(iii) Knee voltage.
(iv) Max Power rating.
(b) Explain the working principle of PIN diode.
(c) Explain the working of varactor diode.

SECTION - III

5. (a) Explain the construction and working principle of PNP transistor.
(b) Explain CB configuration and its characteristics.
(c) Deduce the relation between alpha and beta.

6. (a) Explain output characteristics of transistor in CE mode and indicate cutt off, saturation and active region.
(b) Explain the working of transistor as a switch and amplifier.
(c) List the advantages of ICS.

7. (a) Describe the steps involved in fabrication of monolithic IC.
(b) What is Heat sink? How to select heat sink.
(c) Explain the construction of LASER DIODE? List the applications.

SECTION - IV

8. (a) Explain construction and operation of a N-channel JFET.
(b) Differentiate JFET and BJT.
(c) Explain drain characteristics of JFET with the suitable circuit diagram.

9. (a) Define the JFET parameters and deduce the relations between them.
(b) Describe the construction and working on N-channel enhancement MOSFET.
(c) What are the advantages of CMOS technology.

10. (a) Explain the construction and characteristics of photo diode.
(b) Explain the following terms :
(i) Photo emissivity.
(ii) Photo conductivity.
(iii) Photo voltaic effect.
(c) Explain construction and working of opto coupler.