EC-305 Network Analysis - Nov 2022 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aState and explain Kirchhoff's voltage and current law with an example.
   How to answer

   • Statement of KVL: algebraic sum of voltages around closed loop is zero
   • Statement of KCL: algebraic sum of currents at node is zero
   • Example circuit with explanation for each law
   • Equations and conclusion
2. 7 Marks
   bA series RLC circuit takes a maximum current of 0.3 A at 200 V, 50 Hz. If the voltage across the capacitor is 290V at resonance. Determine R,L,C and Q.

   

   How to answer

   • At resonance current is maximum and impedance is R
   • Calculate R = V/I
   • Use Vc = Q*V to find Q
   • Find L and C from Q and resonant frequency
3. 7 Marks
   aDerive the equation for Equivalent inductance, when two inductors are coupled in series opposing and mutual inductance exists between them.
   How to answer

   • Voltage equations for two coils with mutual term
   • Sign for series opposing connection
   • Total inductance expression L1+L2-2M
   • Final equivalent inductance equation
4. 7 Marks
   bDefine Incidence Matrix for the graph shown in Figure. Find the complete Incidence Matrix.

   

   How to answer

   • Definition of incidence matrix with entries 0,1,-1
   • Identify nodes A,B,C,D and branches 1-6 with orientations
   • Construct complete matrix of size nodes x branches
   • Present final matrix
5. 7 Marks
   aDefine and explain the following with an example:

   1. i)Graph and Subgraph
   2. ii)Oriented Graph
   3. iii)Tree of a Graph
   4. iv)Twigs and Links
   How to answer

   • Definition of graph and subgraph with example
   • Definition of oriented graph with example
   • Definition of tree of a graph with example
   • Definition of twigs and links with example
6. 7 Marks
   bDraw the parallel resonant circuit and derive the expression for resonant frequency
   How to answer

   • Parallel resonant circuit diagram with R,L,C
   • Condition for resonance: susceptance zero
   • Derivation steps for resonant frequency
   • Expression for f0
7. 7 Marks
   aFind the Norton's equivalent circuit for the following circuit

   

   How to answer

   • Find open-circuit voltage / short-circuit current at terminals a-b
   • Deactivate sources to find Norton resistance
   • Draw Norton equivalent with IN parallel RN
   • Mention values
8. 7 Marks
   bFind the voltage drop across $3\Omega$ resistor by Superposition theorem.

   

   How to answer

   • State superposition theorem
   • Consider 10V source alone with current source open
   • Consider 10A source alone with voltage source shorted
   • Add contributions to get voltage across 3 ohm resistor
9. 7 Marks
   aState and explain the Tellegen's theorem with suitable example.
   How to answer

   • Statement of Tellegen's theorem: sum of branch powers is zero
   • Explanation with KCL/KVL basis
   • Suitable example circuit with calculation
   • Conclusion
10. 7 Marks
    bFind the value of $i(0^+)$ using the initial value theorem for the function $I(s) = (2s+3)/[(s+1)(s+3)]$
    How to answer

    • Recall initial value theorem i(0+)=lim s->inf sI(s)
    • Substitute I(s)=(2s+3)/[(s+1)(s+3)]
    • Evaluate limit
    • Obtain i(0+) value
11. 7 Marks
    aIn the network shown in figure below, the switch K is moved from position 'a' to 'b' at t=0. Find the Particular solution for Current i(t).

    

    How to answer

    • Initial condition at t=0- with switch at 'a'
    • Transient equation for RL circuit after switching to 'b'
    • Solve first-order differential equation
    • Particular solution for current i(t)
12. 7 Marks
    bFor the waveform shown in figure below. Write the expression and find the Laplace transform.

    

    How to answer

    • Write time-domain expression using unit step functions
    • Break trapezoidal waveform into ramp segments
    • Apply Laplace transform to each segment
    • Simplify to get V(s)
13. 7 Marks
    aFind the Y-parameter of the circuit as shown in figure below

    

    How to answer

    • Write two-port equations for Y-parameters
    • Apply short-circuit conditions
    • Calculate Y11,Y12,Y21,Y22 with dependent source
    • Present Y-matrix
14. 7 Marks
    bDefine Hybrid parameters of a Two port network. Established the relation between Hybrid Parameters and ABCD Parameters.
    How to answer

    • Define hybrid h-parameters equations
    • Define ABCD transmission parameters
    • Derive conversion formulas
    • State final relations
15. 14 Marks
    Write a short notes on any Two:

    1. i)Image Parameter
    2. ii)Steady State Analysis
    3. iii)Controlled and un controlled sources
    4. iv)Dual Networks
    How to answer

    • Select any two topics from list
    • Give definition and key points for each
    • Add example or diagram where relevant
    • Conclude with applications