Osmania University (OU) 2006-1st Sem B.E Electronics & Tele-Communication Engineering 2/4 (E.C.E)(ESTER)SUPPLEMENTARY ,IL, Basic circuits analysis - Question Paper
B.E 2/4 (E.C.E)(I-SEMESTER)SUPPLEMENTARY EXAMINATION,APRIL,2006
Basic circuits analysis
Code No.: 10011
FACULTY OF ENGINEERING B.E. H/rV Year (ECE) I Semester (Supplementary) Examination, April 2006
basic ciRcyro analysis
Time : 3 HoursI [Max. Marks : 75
Answer all questions of Part A.
Answer five questions from Part B.
Part A - (Marks: 25}
1. A series R-C network with R=10 ohms and C=1F is existed by a dc voltage of 10 volts. Determine the steady state value of the voltage across capacitor and approximate time required to reach this value. 3
2. An inductance of 2H is shunted by 1 ohm resistor and this combination is connected in series with a capacitance of IF. Determine resonant frequency. 3
3. Two mutually coupled coils are connected in series such that mutual fluxes set up by them oppose each other. Determine the equivalent inductance if Lj = 1H, Lg'ss 4H and co-efficient of coupling K = 0.8. 2
4. Draw voltage - current characteristics of ideal and realistic voltage sources. Also, indicate their equivalent electrical circuits. 2
5. The applied voltage and the resulting current in an electrical circuit is given by v = 14.14 sin(wt + 60) and i = J2 sin(wt-30). Determine the power factor of the circuit and Volt-Amperes (VA) delivered to the circuit. 3
6. Define, (a) Q-factor (b) Selectivity (c) Band-width, with reference to resonant circuits. 3
7. An initially relaxed network consisting of 1 ohm resistor and a 2 Farad capacitor is existed' by a voltage u(f.) = 3e l. Determine the current immediately after the application of the voltage. What is the steady state value of this current? 3
8. The graph of electrical network has N nodes and B' branches. The number of links with respect to choice of a tree is given by,
(a) B-N+l (b) B+N (c) N-B+l (d) N-2B +1
Select the correct answer and justify the same. 2
). How do you differentiate between first order and second order circuits? Give examples. , : 1 2
10. If the current in an electrical network is given by, (t) = 2e~3(, what is the time constant of the circuit? 2
Part B - (Marks: 5 x 10 = 50)
1. (a) Obtain the currents ls and I2 for the circuit shown in Fig. 11(a)
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2 a
;42
J8 3 J4
Fig. 11 (a)
(b) In the network of Fig. 11(b), the switch K is closed and a steady state is reached in the network. At t = 0, the switch is opened. Find an expression for the current in inductor, tj (t). 5
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Fig. 11 (b) |
 |
20F
(b) The node equations of a network are given by. (0.45 - J 0.5) Yl - 0.25 V2 and -0.25 V} + (0.75 + j 0.5) V2 = 25 Z.900
(i) Draw the network which has above node equations.
10Z00
5
(ii) Draw the dual of this network.
13. (a) Prove that the resonant frequency of a parallel RLC circuit is the geometric mean of the two half power frequencies. 5
(b) For the network, shown in Fig. 13 (b), (i) Determine resonant frequency
(ii) If the voltage across capacitor is vc = 20 2 sin 0.5t, find the instantaneous current through inductor and applied voltage. 5
Pig. 13 (b)
14. (a) State and prove maximum power transfer theorem.
(b) In a linear RLC network, the following readings are taken At SQHz,
Dj = 5 exp (j 5)
1 12 exp (j 40) i~ 8 exp (j 10) ig = 10 exp (J 15)
v' = 15 exp (-j 20)
AtlQQEs ,
l>j = 10 ej20 v2 = 12 eJ 350 Uo = 5 ej5
i1 = 2 exp (j 25) i2- 10 exp {*j 10) i3 = 14.93 exp [J 68)
Determine U3 as it has not been recorded. 5
15. (a) State and explain superposition theorem. Can this theorem be applied to find power in the circuit? 4
(b) Find the Thevenin's and Norton's equivalent circuit across terminals AB of the network shown in Fig. 15(b).
Hence, find the load impedance that should be connected across terminals AB
of the network for maximum power transfer. What is the power supplied to
this load? _ To 6
a52 A '*
 |
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Fig. 15 (b) |
O B
16. (a) The current source connected to the network shown in Fjg. 16(a) is described by the equation, tj * 5 2 Sin 10001 Determine the effective current in each element and also the complex power for each element in the network and total complex power for the network* 5
100|AF
3 20mH %30Q
Fig. 16 (a)
(b) For the network shown in Fig. 16(b), find va{t} in the steady state if iv** 2 sin 21
 |
2a vaW | Fig. 16(b) |
17. (a) Explain the following terms, as they refer to Network Topology.
(i) Cutset (ii) Tree (lift Chord. 4
(b) Obtain the fundamental circuit matrix for the graph shown in Fig. 17(b). Choose the tree consisting of branches 6, 7% 8, 9. Write KVL & KCL equations for the graph. 4 6
Fig. 17 (b)
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Attachment: |
| Earning: Approval pending. |
