Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 3rd Semester (Third Semester) 2017-2018 REC302 Electonic Devices And Circuits Question Paper
Paper ID:3008
B.TECH
(SEM III) THEORY EXAMINATION 2017-18
ELECTONIC DEVICES AND CIRCUITS
T ime: 3 Hours T 0tal Marks: 70
Note: 1. Attempt all Sections. If require any missing data; then choose suitably.
SECTION A
1. Attempt all questions in brief.
(a) Mention the advantages of negative feedback.
(b)What do you mean by Base Width Modulation in BJT.
(c)What is ?uorescence?
(d)How does direct recombination lifetime differ from indirect recombination lifetime?
(e) Brief the Avalanche breakdown mechanism.
(1) Differentiate EMOSFET with DMOSFET
(g) Find the current gain [3 in CE configuration of BJT, if (x = 0.98.
SECTION B
Q.2 Attempt any three of the following (7x3=21)
(a) Draw the CE amplifier with a resistance connected in Emitter and derive the
expression for different characterizing parameters.
(b) Discuss the various internal capacitances for BJ T and MOSFET.
(0) Explain the phenomenon of luminescence. What are its different types? How does
?uorescence differ from phosphorescence? Discuss its application as a ?uorescence
lamp.
(d) What is Einstein relation? Develop an expression to establish relation between
diffusion coefficient & mobility of carriers.
(e) Boron is implanted in to a n- type Si sample having donar concentration of 1016/cm3,
to form abrupt junction. If the acceptor concentration in P?type region is 4X1018/cm3,
determine the
(i) Width of the depletion region
(ii) depth of penetration on n-side & p-side at equilibrium. Take room temperature as 27?C;
n1: 1.5 X1010/cm3 & relative permittivity of boron as 11.8.
Section C
Q.3 Attempt Any one part of the following (7x1=7)
(a) Draw the four basic feedback topologies. Compare the Input and output resistance
among the feedback topolologies.
(b) Explain the working of common source amplifier with a resistance is connected in
source
Lead. Draw its small signal equivalent circuit. Deduce the expression for overall voltage
gain.
Q.4 Attempt Any one part of the following (7x1=7)
(a) Differentiate between direct and indirect band gap semiconductor. Also discuss
the variation of energy band with alloy composition.
(b)What do you mean by Fermi level? Discuss the effect of temperature & doping on
mobility. A Si sample is doped with 1017 As atoms/cm3. What is the equilibrium hole
concentration on P0 at 300K? Where is E: relative to Ei.
Q.5 Attempt Any one part of the following (7x1=7)
(a)Design the circuit shown in the fig to establish a drain voltage of 0. 1V what is the
effective resistance between drain and source at this operating point? Let Vf=1V,
and Kn(W/L)=1mA\V2.
Vbb = 5V
Rb
F???>Vb=0vl\l
(b) Construct P channel enhancement MOSFET. Draw and explain the I-V characteristics when VDs
is increased
Q6 Attempt Any one part of the following (7x1=7)
(a) How B] T can be used as a ampli?er and as a switch ? J ustify using required circuit
,waveform, mathematical expression.
(b) Mention the different biasing technique used in BJT. Explain any two of them.
Q7 Attempt Any one part of the following (7x1=7)
(a) Draw the high frequency hybrid- 71: model of MOSFET?
and Show that fT=gm/2 u(Cgs +ng)
(b) Mention the conditions for oscillation. Derive the expression for frequency of oscillation
in Phase shift Oscillator
This post was last modified on 29 January 2020