Andhra University 2008 B.E MATERIAL SCIENCE - Question Paper

I Year B.E./B.Tech Degree exams

MATERIAL SCIENCE

(Common to EEE & ECE Branches)

Time : 3 hours Maximum : 75 Marks
ques. one is compulsory

ans any 4 from ques. two to 8

All ques. carry marks

18

1. a) explain the behavior of a P-N junction under forward and

reverse biasing. (3m)

b) discuss the operation of transistor as an amplifier

(3m)

c) Draw the h-parameter equivalent circuits of a transistor in

various configurations (3m)
d) describe the subsequent for a JFET

i) The Pinch-off voltage

ii) Drain resistance


iii) Transconductance (3m)

e) In a centre - tapped full-wave rectifier, 2 diodes with

10 , f R = W , rR= ¥ 0 Vg = are used. The load resistance

1000 . L R= WFind a) peak dc and rms load currents b) dc

output voltage and dc power if a 24 volts peak sinusoidal

signal is applied. (3m)

2. a) Draw the space charge, electric field and electrostatic


potential as a function of distance across an open circuited

PN junction and discuss the nature of these curves. discuss

the significance of potential barrier across the junction.

(8m)

Earning:   Approval pending.