Question Paper: Network Theory Question Paper - December 2013 - Electronics and Telecom Engineering (Semester 3) - Savitribai Phule Pune University (SPPU)
0

## Network Theory - December 2013

### SPPU Electronics and Telecom Engineering (Semester 3)

Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

### Answer any one question from Q1 and Q2

1 (a) Apply mesh analysis and determine the currents I1 and I2.
6 marks

1 (b) Explain the following terms with example:
i) Oriented graph.
ii) Tieset matrix.
iii) f-cutset matrix.
6 marks

2 (a) Consider the circuit given below:
i) Obtain Thevenin's equivalent circuit.
ii) What load should be connected between terminals A-B for maximum power- transfer to the load?
iii) Calculate the maximum power transferred to the load.
6 marks

2 (b) For the circuit and its graph shown below:
i) Write a tie-set schedule for the tree [4, 5, 6].
ii) Find the branch-impedance matrix.
iii) Obtain the loop impedance matrix.
6 marks

### Answer any one question from Q3 and Q4

3 (a) For the circuit shown below, find the voltage vc at t=200 μs. Find the expression for the current through capacitor ic(t).
6 marks

3 (b) Define the term Quality factor. Prove for a series RLC resonant circuit <msub><mi>f</mi><mn>0</mn></msub><mo>=</mo><msqrt><msub><mi>f</mi><mn>1</mn></msub><msub><mi>f</mi><mn>2</mn></msub></msqrt>[/itex]" role="presentation" style="font-size: 125%; text-align: center; position: relative;">f0=f1f2<math xmlns="https://www.w3.org/1998/Math/MathML" display="block"><msub><mi>f</mi><mn>0</mn></msub><mo>=</mo><msqrt><msub><mi>f</mi><mn>1</mn></msub><msub><mi>f</mi><mn>2</mn></msub></msqrt>[/itex]<script type="math/tex; mode=display" id="MathJax-Element-1"> f_0 = \sqrt{f_1 f_2} </script> 6 marks

4 (a) Derive the expression for the current i(t) for the series RL circuit shown below:
6 marks

4 (b) A series resonant circuit has a bandwidth of 100 Hz and contains a 20 mH inductance and a 20 μF capacitance. Determine:
i) f0
ii) Q0 and
iii) Impedance Z at resonance.
6 marks

### Answer any one question from Q5 and Q6

5 (a) For any symmetrical network, prove that the characteristics impedanceZ0 is the geometric-mean of open & short circuit impedances. 6 marks

5 (b) Design a constant-k T-type low pass filter with following specifications: Design resistance R0 = 560 ? and cut-off frequency fc = 2KHz. Also determine the frequency at which the attenuation offered by the filter is 17.372dB. 6 marks

6 (a) Design a symmetrical π attenuator with following specifications: Attenuation = 6dB and characteristic resistance of 6 dB. Draw a neat diagram of the properly terminated attenuator showing the component values. 6 marks

i) State the limitations of prototype filters.
ii) Explain how these limitations are overcome using m-derived filters.
iii) Draw the block diagram of composite filters.
6 marks

### Answer any one question from Q7 and Q8

7 (a) Find z-parameters for the two-port network shown below. State whether the network is symmetrical/reciprocal.
6 marks

7 (b) Consider the RC network shown below.
i) Draw the s-domain equivalent circuit.
ii) Find the transfer function <mi>H</mi><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo><mo>=</mo><mstyle displaystyle="true" scriptlevel="0"><mfrac><mrow><msub><mi>V</mi><mrow class="MJX-TeXAtom-ORD"><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo></mrow><mrow><msub><mi>V</mi><mi>i</mi></msub><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo></mrow></mfrac></mstyle>[/itex]" role="presentation" style="font-size: 125%; text-align: center; position: relative;">H(S)=Vout(S)Vi(S)<math xmlns="https://www.w3.org/1998/Math/MathML" display="block"><mi>H</mi><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo><mo>=</mo><mstyle displaystyle="true" scriptlevel="0"><mfrac><mrow><msub><mi>V</mi><mrow class="MJX-TeXAtom-ORD"><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo></mrow><mrow><msub><mi>V</mi><mi>i</mi></msub><mo stretchy="false">(</mo><mi>S</mi><mo stretchy="false">)</mo></mrow></mfrac></mstyle>[/itex]<script type="math/tex; mode=display" id="MathJax-Element-2"> H(S)= \dfrac {V_{out}(S)}{V_i (S)} </script> iii) Find the poles and zeros of the function H(s) and
iv) State whether the snystem is stable or not.
6 marks

8 (a) Find the four short circuit admittance parameters for the resistive two port network. Determine whether the network is symmetrical/reciprocal.
6 marks

8 (b) State and explain:
i) Driving point functions for one port networks.
ii) Driving point and transfer functions for two port networks.
6 marks

question paper pu • 121 views