Download PTU B-Tech ECE 2020 Dec 3rd Sem 76447 Network Theory Question Paper

Download PTU (I.K.Gujral Punjab Technical University (IKGPTU)) B-Tech (Bachelor of Technology) (ECE)-Electronics And Communications Engineering 2020 December 3rd Sem 76447 Network Theory Previous Question Paper

Roll No.
Total No. of Pages : 03
Total No. of Questions : 18
B.Tech. (ECE) (2018 Batch) (Sem.?3)
NETWORK THEORY
Subject Code : BTEC-304-18
M.Code : 76447
Time : 3 Hrs. Max. Marks : 60
INST RUCT IONS T O CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt any FOUR q ues tions.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt any T WO questio ns.
SECTION-A
Write briefly :
1.
State reciprocity theorem and its applications.
2.
Find convolution of f1(t)=2u(t) and f2(t)=e?3t u(t),where u(t) is a step function.
3.
Define hybrid parameters with equations and application,
4.
A series RL circuit has R=1K , L=10mH and C=2 F. Find the Transfer function of the
circuit.
5.
Define the necessary and sufficient conditions for a polynomial to be Hurwitz.
6.
Z parameters are Z11 = 10, Z22 = 20, Z12 = Z21 = 5. Find equivalent T network.
7.
Obtain the image impedance for a T-network for which the resistance of three arms are
equal to 3.
8.
Give the difference in properties of RC, RL and LC circuit.
9.
State the advantages of 3-phase supply over single phase.
10. For a series RC circuit excited by 10V ac voltage, with a time constant sec. Find the
voltage across C at time t.
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SECTION-B
11. For the given two port network calculate the hybrid parameters of Fig. 1.
1
2
I1
110
0
I2
5
12
1
2
5
1
'
2'
FIG.1
12. Find whether the given function is a positive real function?
2
2s 5s 1
F s
3
2
s 2s s 2
13. Find the Fourier transform of the pulse as shown in Fig. 2
V(t)
V0
T
2T
3T t
FIG.2
14. In the circuit shown, steady state is reached with switch open. Switch is closed at t=0.
Determine i(t) for t > 0. (Fig. 3)
10
S
t = 0
1H
2F
10V
FIG.3
15. A delta connected three phase load has 10 < 0?, 5 < ?90? and 2 < 90?. The supply voltage is
400V, 50Hz. Calculate the line currents for RBY phase sequence.
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SECTION-C
16. The driving point impedance is given by :
s 2
s 9
Z s
2
s 5 2
s 13
Obtain the Foster-I and Foster-II forms.
17. What do you mean by balanced and unbalanced loads? Explain Millman's theorem for
unbalanced loads with diagram and equations.
18. Obtain the trigonometric form of Fourier series expansion of the rectified sine wave of
Fig.4.
f t
( )
A
O
2
3
t
FIG.4
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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