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Register No.
SNS COLLEGE OF ENGINEERING
Kurumbapalayam(Po), Coimbatore – 641 107
Accredited by NAAC-UGC with ‘A’ Grade
Approved by AICTE & Affiliated to Anna University, Chennai
INTERNAL ASSESMENT EXAMINATIONS - I
COURSE: B.E – ECE
EC6201 – ELECTRONIC DEVICES
Sem &Class: II Sem ECE A &B
Duration: 2 Hours
Date: 7 Feb 2017
Maximum: 66 Marks
Answer ALL questions
PART A - (9 X 2 = 18 marks)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Define diffusion current.
Sketch the V-I characteristics of PN junction diode.
What is meant by Storage time?
What are the applications of PN diode?
Mention the two types of junction capacitances.
Write the equation for drift and diffusion current density.
Draw the input characteristics of CE transistor.
A transistor has β= 150,find the collector and base current ,if IE= 10mA
Write the difference between unipolar and bipolar transistor?
CO-I
CO-I
CO-I
CO-I
CO-I
CO-I
CO-II
CO-II
CO-II
K-1
K-1
K-2
K-1
K-1
CO-I
K-5
CO-I
K-4
CO-I
K-3
CO-I
K-5
12
CO-I
K-3
4
CO-I
K-4
2
2
2
2
2
2
2
2
2
K-2
K-2
K-4
K-2
PART B - (3 X 16 = 48 marks)
1.
(a)
(b)
(i)
Explain the operation of pn junction diode under zero voltage
applied bias condition and derive the expression for built in
potential barrier.
OR
With relevant expression and figures, describe diffusion and drift
current density.
(ii) Consider a Si PN junction at T= 300K with doping concentrations
of Na= 1016cm-3 and Nd=1015cm-3. Assume that ni = 1.5x1010cm3.
Calculate width of the space charge region in a PN Junction,
when a reverse bias voltage VR=5V is applied.
2.
(a)
Derive the PN diode current equation from the quantitative theory
of diode currents.
OR
(b)
(i) Write short notes on diode switching characteristics.
(ii) Describe the action of PN junction diode under reverse bias
condition.
1
16
12
4
16
3.
(a) (i)
Explain with neat diagram the operation of NPN transistor.
(ii) Compare the characteristics of CE,CB and CC configuration of
transistors.
OR
(b)
Draw the circuit for the CE Configuration of a NPN transistor and
explain brief its input and output characteristics.
*****
2
10
CO-II
K-3
6
CO-II
K-5
CO-II
K-5
16