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Circuits and Networks : Question Paper Dec 2014 - Electronics & Telecomm (Semester 3) | Gujarat Technological University (GTU)

## Circuits and Networks - Dec 2014

### Electronics and Comm. Engg. (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) Define Charge, Current, Potential difference, Lumped parameter, Time invariant, Branch and Tree.(7 marks) 1 (b) Calculate the node voltages for all the nodes shown in figure: 1 using nodal analysis. (7 marks) 2 (a) State and explain the Maximum Power Transfer Theorem. Drive the condition for maximum power transfer to the load for DC and AC circuit.(7 marks)

### Answer any one question from Q2 (b) & Q2 (c)

2 (b) Draw the dual network shown in figure : 2. (7 marks) 2 (c) Explain the dot convention rule for the magnetically coupled Network shown in figure: 3. Also formulates KVL equations. (7 marks)

### Answer any two question from Q3 (a), (b) & Q3 (c), (d)

3 (a) For the circuit shown in figure: 4 find the voltages and currents for all circuit elements using mesh analysis. (7 marks) 3 (b) State and explain (1) Norton's theorem (2) Milllman's theorem.(7 marks) 3 (c) Find current in 20 ohm resistance in the circuit shown in figure: 5 using superposition theorem. (7 marks) 3 (d) State Thevenin's theorem. Calculate current passing through 60Ω resistance in the circuit shown in figure: 6, using thevenin's theorem. (7 marks)

### Answer any two question from Q4 (a), (b) & Q4 (c), (b)

4 (a) In the circuit shown in figure: 7, the switch "K" is closed at t=0. Assuming no initial current through inductor. Find current at t = 0.3 sec. Also find instant of time at which voltage across R equals voltage across L. (7 marks) 4 (b) Find laplace transform of f1(t)=sin ωt f2(t)=e-at cos ωt.(7 marks) 4 (c) In a circuit shown in figure: 8, the switch has been at position A for a long time and is moved to position B at t = 0. Obtain current i(t) at t > 0. (7 marks) 4 (d) Explain the concept of Poles and zeros and their significance.(7 marks)

### Answer any two question from Q5(a), (b) & Q5 (c), (d)

5 (a) Find h-parameters of the circuit shown in figure (7 marks) 5 (b) Derive expression of ABCD parameters in terms of Z and Y parameters.(7 marks) 5 (c) Derive relationship between incidence matrix (A), fundamental cut-set matrix (Qf) and fundamental tie-set matrix (Bf).(7 marks) 5 (d) For the network shown in figure: 10 draw the oriented graph and Obtain (1) the incidence matrix (2) tieset matrix and (3) f-cutset matrix. (7 marks)

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