DipIETE – ET/CS (NEW SCHEME) - Code:
DE52/DC52
Subject: FUNDAMENTALS OF ELECTRICAL &
ELECTRONICS ENGINEERING
Time: 3 Hours
Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is
compulsory and carries 20 marks. Answer to Q. 1 must be written in the space
provided for it in the answer book supplied and nowhere else.
· Out of the
remaining EIGHT Questions answer any FIVE Questions, selecting at least TWO
questions from each part. Each question carries 16 marks.
· Any required data
not explicitly given, may be suitably assumed and stated.
Q.1 Choose the correct or the best alternative in the following: (2
10)
a. Electrostatics
deals with __________.
(A) static
charges (B) dynamic charges
(C) static
and dynamic charges (D) none.
b. Find the force on charge
due to charge 
where 
is at (0, 1, 2)m and 
at (2, 0, 0)m.
(A) 6 N (B) 5 N
(C) 10 N (D) 9 N
c. A
static magnetic field can originate from ________.
(A) varying
current
(B) permanent
magnet
(C) either
a constant current or a permanent magnet
(D) none
d. Find 
in circuit as shown in
Fig.1.
(A) 3A
(B) 1A
(C) 4A
(D) 6A
e. A
series R-L-C circuit consisting of 
and 
is connected across an
ac supply of 200 V rms. The rms voltage
across the capacitor is
(A) 
(B) 
(C) 
(D) 
f. For
an emitter current bias circuit with 
. What is the value of
?
(A) 
(B) 
(C) 
(D) 
g. For a
collector-to-base bias circuit 
, . The value of 
and 
are
(A) 
and 
(B) 
and 
(C) 
and 
(D) 
and 
h. One
of the commonest applications of Zener diode is a ___________.
(A)
rectifier (B)
simple voltage reference source
(C) clipper (D) emitter
follower
i. For
BJT to work as an amplifier, the Q-point should be in ______ region.
(A) saturation (B) cut-off
(C) active (D) none
j. A
certain transistor has current gain 
of 0.99 in CB
configuration. Calculate current gain in
CE configuration.
(A) 99 (B) 88
(C) 77 (D) 66
PART A
Answer atleast TWO questions.
Each question carries 16 marks.
Q.2 a. For
the circuit shown in Fig.2, determine the current in all branches for the
applied voltage (V). (4)
b. Find
the current i using the principle of superposition in Fig.3. (5)
c. Find
the following parameters given for the voltage, V = 200 sin 314t.
(i) Frequency (ii) Form factor
(iii) crest factor. (7)
Q.3 a. State
and explain Coulomb’s law of force between two point charges and mention the
units of quantities in the force equation. (4)
b. A metal rod wound with 3500
turns is 25 cm long and 2.5 cm in diameter.
It is bent into a closed ring and when a current of 0.6A is passed
through it, the flux density in it is
. Assuming that all the flux links with every turn of the coil.
Calculate:
(i) The relative permeability of metal.
(ii) The self-inductance of the coil.
(iii) emf induced in the coil, when the current
through the coil is interrupted and
the value of flux in iron portion falls to 8 percent of its original value in
0.0015 sec. (8)
c. Tabulate
the similarities and dis-similarities of the electric and magnetic circuits. (4)
Q.4 a. Explain
the principle of operation of DC motor with neat diagram. (5)
b. A
Lap-wound DC shunt generator having 80 slots with 10 conductors per slot
generates at no load an emf of 400V, when running at 1000 rpm. At what speed should it be rotated to
generate a voltage of 220 V on open circuit. (7)
c. Discuss the motor characteristic curves. (4)
Q.5 a. Explain
the classification of Transformers. (6)
b. An
8-pole attenuator runs at 750 rpm. It
supplies power to a 6-pole, 3-phase induction motor, which has a full load slip
of 3%. Find the full load speed of the
induction motor and the frequency of its rotor emf. (6)
c. The required no-load voltage ratio in a
single phase 50 Hz, core type transformer is
. Find the number of
turns in each winding if the flux is to be 0.06 Wb. (4)
PART B
Answer atleast TWO questions.
Each question carries 16 marks.
Q.6 a. Give
a brief note on conductor, insulator and semiconductor. (8)
b. Explain
the representation of p-type and n-type semiconductor materials along with
diffusion of charge carrier across pn-junction. (8)
Q.7 a. Sketch and explain with neat diagram and also
with relevant equations the working of full wave bridge rectifier. (8)
b. Sketch
a negative series clipper circuit and positive shunt clipper circuit. Show input and output waveforms and explain. (8)
Q.8 a. Sketch and explain the shape of the common
emitter input and output characteristics.
Explain how the characteristics are determined experimentally. (8)
b. For
an emitter current bias, derive an accurate equation for the collector current 
in terms of the supply
voltage and circuit resistors. (8)
Q.9 a. Sketch and explain the circuit of a two-stage
capacitor-coupled common emitter amplifier with necessary equations. (8)
b. Sketch
the circuit of a phase shift oscillator that uses an IC operational
amplifier. Show the amplifier input and
output waveforms and briefly explain how the circuit operates. (8)