DipIETE – ET (OLD SCHEME)
Code: DE07 Subject: NETWORK AND
TRANSMISSION LINES
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. 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. Maximum power
transfer theorem finds application in ________.
(A) power
Circuits
(B) communication
Circuits
(C) distribution
Circuits
(D) both power and
Communication Circuits
b. The integral of
a step function is _________.
(A) a
ramp Function (B) an impulse function
(C) a modified
ramp function (D) a sinusoid function
c. For
a symmetrical networks
(A) h11
= h22 (B)
h12= h21
(C) h11h22
–h12h21=0 (D) h11h22–h12h21=1
d. A constant k
band pass filter has band from 1000 to 4000 Hz. The resonant frequency of shunt
and series arm is _________.
(A) 2500
Hz (B) 1500 Hz
(C) 2000
Hz (D) 3000 Hz
e. A
prototype low pass filter has ____________.
(A) inductance
in both series and shunt arms
(B) inductance in series arm and
capacitance in shunt arm
(C) capacitance
in series arm and inductance in shunt arm
(D) capacitance in
both series and shunt arms
f. A
network has R and C in series.
inverse network will have __________.
(A) R and
L in parallel (B) R and L in series
(C) L and
C in parallel (D) L and C in series
g.
(A) steady
state
(B) transient state
(C) both
steady and transient state
(D) transient state
provided forcing functions do not exist
h. In a series
resonant circuit, the resonant frequency is __________.
(A) geometric
mean of half power frequencies
(B) arithmetic mean of half power
frequencies
(C) difference
of half power frequencies
(D) None of the above
i. The relation
AD – BC = 1 where A, B, C, D, are transmission parameters of a network is valid
for __________.
(A) every
network
(B) passive but not reciprocal network
(C) passive
and reciprocal network
(D) both active and
passive network
j. The
attenuation characteristics of a loaded line is similar to that of _______.
(A) low
pass filter (B) high pass filter
(C) band
pass filter (D) band stop filter
Answer any FIVE
Questions out of EIGHT Questions.
Each question
carries 16 marks.
Q.2 Distinguish between: (44)
(i)
Unilateral
& Bilateral elements.
(ii) Balanced & unbalanced network.
(iii)
Linear & non linear elements.
(iv) Active and passive
elements.
Q.3 Write
down the applications & limitations of: (4 4)
(i) Superposition Theorem
(ii) Thevenin’s Norton’s Theorem
(iii) Millman’s Theorem
(iv) Substitution Theorem
Q.4 a. Define
attenuators. Explain briefly symmetrical and asymmetrical attenuators. (2+4+4)
b. The
component values of a symmetrical lattice attenuator are given by: straight arm
resistance R1 = 245.45 ohms and crass arm resistance R2 =
366.6 ohms. Find the characteristics impedance and attenuation in (dB) caused
by the attenuator. (6)
Q.5 a. Explain
various types of losses in a transmission line. (8)
b. A
line has a = 0.005
nippers/km and b = 0.02 rad/km.
The line length is 10 km. find the total attenuation in (dB) and wave velocity.
The frequency is 1000 Hz. (8)
Q.6 a. What are the necessary
conditions for transfer functions? (8)
b.
Design a symmetrical p network having an Zoc = 750 ohms and Zsc = 480 ohms. (8)
Q.7 a. A
choke with an inductance of 20 H and a resistance of 16 ohms is commented
through a switch to a 24 V source of emf. (8)
(i) What is the initial current when the switch
is closed?
(ii) What is the initial rate of change of current
when switch is closed?
(iii) What is the final
steady state current?
(iv) What is the current at the instant of 1.25 sec
after switching?
b. A series circuit has a resistance of 4 ohms,
an inductive reactance of 1 H and a variable capacitor. It is connected to a 100
volts 50 Hz supply. Calculate: (8)
(i) Capacitance of capacitor at resonance.
(ii) Current at resonance.
(iii) Voltage across each
component.
(iv) Voltage magnification factor.
(v) Q of
the circuit.
Q.8 a. A
power supply gives a sinusoidal output of 12 V at a frequency of 1 KHz. The internal
resistance and inductance of the supply are 20 ohms and 10 mH respectively. Find: (8)
(i) The maximum power output that this supply
can deliver and the
parameters of the load for this
condition.
(ii) The maximum power output that this supply can
deliver to a
purely
resistive load.
b. Find
the
Q.9 Write short note on the following: (44)
(i) Lattice
Network.
(ii) Double Tuned circuit.
(iii)
Double stub matching.
(iv)
Convolution Integral.