Bangalore University Diploma Instrumentation & Control Engineering SEMICONDUCTOR DEVICES (Course Code EP, EC & IC) 2005 Question paper

Second Semester Diploma (Annual) Examination.
E & C Board
SEMICONDUCTOR DEVICES
(Course Code EP, EC & IC)

Time : 3 Hours Max. Marks : 100

Note : i) Question No. 1 of Section – I is compulsory
ii) Answer any six full questions choosing two questions each from Sections-II, III and IV.

Section - I

1.a) Fill in the blanks with appropriate word / words:
i) A semiconductor has ………….. temperature co-efficient of resistance.
ii) Varactor diode is always ……………. biased.
iii) A tunnel diode is a …………….. PN junction diode.
iv) The noise level in JFET is ............ as compared to ordinary transistor.
v) CMOS has a ............ power consumption.

b) Write short notes on burglar alarm and smoke detector.

Section - II

2. a) What is PN Junction? Explain the formation of depletion layer in a PN Junction?
b) What are donor and acceptor impurities? Explain with examples.
c) What is barrier potential? Give its value for germanium and silicon.

3. a) With the help of suitable diagram, explain the V-I characteristics of PN Junction diode.
b) What are an ideal diode and a real diode? Explain.
c) List the applications of a Junction diode.

4. a) Explain the output characteristics of a common base NPN transistor. Indicate the active, cut-off and saturation regions.
b) If a transistor has Ic = 4.8 mA, Ib = 100 mA and IE = 4.9 mA, calculate the values of a and b.
c) Write a short note on Heat sink.

Section - III

5. a) Explain the transfer and draw characteristics of a JFET.
b) Define the following terms for JFET
i) Drain Resistance (rd)
ii) Transconductance (gm)
iii) Amplification factor m
c)Explain the working of a transistor as a switch.

6. a) Explain the construction and operation of enhancement type MOSFET.
b) Compare JFET with MOSFET.
c) Explain the advantages of N-channel MOSFET over P-channel.

7. a)Explain the V-I characteristics of UJT and indicate how it exhibits negative resistance property.
b) List the applications of UJT.
c) Explain the working of CMOS inverter.

Section - IV

8. a)Explain the construction and working principle of a Tunnel diode.
b)Explain Opto coupler.
c)List the application of a PIN diode

9. a)Explain the construction, working principle and characteristics of a photo transistor.
b) Explain the working of a LASER.
c) List the applications of GUNN diode.

10. a) Explain the processes involved in the fabrication of monolithic ICs.
b) Define SSI, MSI, LSI and VLSI.
c) Write a short note on IMPATT diode.