University of Mumbai 2007-4th Sem B.E Electrical and Electronics Engineering Electrical Networks-II - - Question Paper
(3 Hours} L"' 1 i Total MarTTrrW-X
N.B. (1) Question No. 1 Is compulsory. A/V
(2) Attempt any four from Ihe remaining questions.
1. (a) A series RL circuit with R* 10 ft and L * 0 2 H has constant voltage V = 50V applied at I = 0. 4
Find and draw the resulting current using Laplace transform method.
(b) Find z-parameters in terms of h-parameters. 4
(c) Explain the properties of positive real function. 4
(d) Explain following symmetries in Fourier Series. 4
(i) Half Wave Symmetry
(ii) Even Function Symmetry
(iii). Odd Function Symmetry.
(e) State the important properties of LC network function. 4
2. (a) The series RC circuit has sinusoidal source us 180 sin (2000t + 4) volts. An initial charge on 8
capacitor is 125 mC with polarity as shown in the figure. Determine tne current if Ihe switch is closed at a time corresponding to $ * 90. Use Laplace transform method.
3. (a) Determine trignometric and exponential form of Fourier Series for the foliov. ng periodic function. 12
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(b) Find the Laplace Transform of the following signal. | |
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*-4r |
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(o) For the network shown below determine the voltage across a capacitor when the switch is closed at t * 0. Assume there is no initial charge on capacitor. Use Laplace transform method. |
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(b) Determine Fourier Transform of the signal using suitable properties.
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fc |
4. (a) Check whether the following polynomial is Hurwitz or not P(j) * s7 + 2se + 2efi + 2s4 + 4s3 + 8s2 + 8s + 4.
(b) Check whether the following function is positive real function or not.
s(s2 f
)
F(s)
(s2 + l) (s2 + 6 j
(c) Poles aid Zeros are given for a function Z(s) as Poles 0 , - 2
10
10
Zeros -1 , - 3
and Z{) s 4 Determine Z{s) and synthesise it using any form.
5. (a) Find Y-paramters for the network shown below :
(b) Find Z-parameters for the network shown below :
10
+
6. (a) The transfer function is given by | r5
H(s)
( s2 +4)| s +5)
Determine its time domain response (using graphical method only),
(b) The Fourier Transform of a continuous time signal f(t) is given by
10
F(w)
jw +4
Determine Fourier Transform Y{w) If
(i) y (t) =e"* f(t)
(ii) y(t) = (2t - 3| f(t)
(c) Derive the condition for reciprocity and symmetry for ABCD parameters.
(d) Synthesise the following function using Caur II form.
sts2 +3)(S2 +5) (s2 +2 Ks2 +4)
Z<8)
7. (a) In the circuit shown below the network is in stady stae with switch 'S* is open. At t * 0, switch is 12 closed. Determine VA (0-), VA(0+) . V0(O-), VB(0*)- Also find VB(t) at t > 0.
I osi.
(b) In the circuit shown below, switch is initially at position A. On the steady state having reached, switch is changed to position B. Find current i(t) and Draw current waveform.
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Attachment: |
| Earning: Approval pending. |
