Download PTU B.Tech 2021 Jan ECE 3rd Sem 78749 Network Theory Question Paper

Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January ECE 3rd Sem 78749 Network Theory Previous Question Paper

Roll No.
Total No. of Pages : 03
Total No. of Questions : 18
B.Tech. (ECE) (Sem.?3 )
NETWORK THEORY
Subject Code : UC-BTEC-304-19
M.Code : 78749
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.
Relate unit impulse, unit step and unit ramp signals?
2.
Draw waveform for the function f (t) = u (t) ? r (t ? 1) + r (t ? 2).
3.
Differentiate between series and parallel resonance.
4.
Draw h-model for BJT and write its characteristics equations.
5.
Under what conditions we can transfer maximum power to the load?
6.
How Routh-Hurwitz criterion is helpful in determining of system stability?
7.
What are Dirichlet's conditions for Fourier Series?
8.
Define image impedance for a 2-port network.
9.
What is current division rule?
10. What are transmission parameters? Give characteristic equations.
SECTION-B
11. Solve following differential equation using Laplace Transform
y ? 5y + 6y = 0, y (0) = 2, y (0) = 0
1 | M - 7 8 7 4 9
( S 2 ) - 6 9 4

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12. In reference to following star-delta equivalent circuits, determine Ra, Rb and Rc in delta
connections when R1 = 6, R1 = 18 and R1 = 3.
N3
N3
R3
R
R
b
a
R1
N
R
1
N2
2
Rc
N
N
1
2
FIG. 1
13. Determine Z-parameters for following 2-port network.
10
10
10
10
10
FIG. 2
14. Determine and plot output voltage V0 (t) in following circuit when input voltage signal is
given by Vi (t) = u (t) ? u (t ?1)
L
+
+
I
R
V
V
i
0
?
?
FIG. 3
15. Determine if following system H(s) is a stable system or not. Explain with reasons.
4
3
2
s 2s s 3s 4
H(s) =
5
4
3
2
s 3s 2s s 2s 1
2 | M - 7 8 7 4 9
( S 2 ) - 6 9 4

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SECTION-C
16. Derive conversion formulas for 2-port networks:
a) h-parameters into ABCD-parameters
b) ABCD-parameters into Z-parameters
17. Synthesize following 1-port networks
2
2
10(s 4) (s 25)
a) Z(s) =
using Foster-1 Form
2
s(s 9)
3
s 4s
b) Z(s) =
using Cauer-1 Form
4
s 20s 9
18. a) Design constant-k (T-section & -section) Low Pass Filters for given cut-off frequency
fc = 2000 Hz and design impedance Ro = 400.
b) What are the advantages and disadvantages of both constant-k and m-derived filters?
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.
3 | M - 7 8 7 4 9
( S 2 ) - 6 9 4

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