EC3251 Circuit Analysis Previous Year Question Papers - Anna University

UNIT I: DC Circuit Analysis

Part A (2 Marks)

• State Ohm's Law and its limitations.
• State Kirchhoff's Current Law (KCL) and Voltage Law (KVL).
• Define active and passive elements with examples.
• Explain the difference between a mesh and a loop.

Part B (13/16 Marks)

• Mesh Analysis: Find branch currents using loop equations (including dependent sources).
• Nodal Analysis: Determine node voltages using KCL.
• Kirchhoff's Laws: Application to complex DC circuits.
• Series & Parallel Circuits: Equivalent resistance and power calculations.

UNIT II: Network Theorems and Duality

Part A (2 Marks)

• State Superposition Theorem.
• Define Thevenin's and Norton's theorems.
• Condition for Maximum Power Transfer.
• Define Duality and list dual quantities.

Part B (13/16 Marks)

• Thevenin's Theorem: Find equivalent circuit and load current.
• Norton's Theorem: Conversion and application.
• Superposition Theorem: Solve circuits with multiple sources.
• Maximum Power Transfer: Derivation and numerical problems.
• Delta–Wye Transformation: Convert and solve networks.

UNIT III: Sinusoidal Steady State Analysis

Part A (2 Marks)

• Define Power Factor, Real Power, Reactive Power.
• What is a Phasor?
• Differentiate Apparent, Average, and Complex Power.

Part B (13/16 Marks)

• Phasor Analysis of R, L, C circuits.
• AC Power Analysis: Power factor, impedance triangle, phasor diagram.
• Series & Parallel RLC circuits.
• Steady-state response using phasor method.

UNIT IV: Transients and Resonance

Part A (2 Marks)

• Define Quality Factor (Q) and Selectivity.
• What is Resonant Frequency?
• Define Time Constant for RC and RL circuits.

Part B (13/16 Marks)

• Transient Analysis: RL, RC, RLC circuits (step response).
• Series Resonance: Frequency, bandwidth, Q-factor.
• Parallel Resonance: Condition and characteristics.
• Frequency Response of RLC circuits.

UNIT V: Coupled Circuits and Topology

Part A (2 Marks)

• Define Mutual Inductance and Coefficient of Coupling.
• What is an Ideal Transformer?
• Define Tree, Link, and Twig.

Part B (13/16 Marks)

• Coupled Circuits: Series aiding/opposing, mutual inductance problems.
• Transformers: Analysis using equivalent circuits.
• Network Topology: Incidence matrix, tie-set, cut-set.

Most Repeated / High-Weight Questions

Mesh & Nodal analysis numericals (Unit I), Thevenin + Superposition + Maximum Power Transfer (Unit II - very high weight), Phasor analysis + power factor (Unit III), Transients + resonance formulas (Unit IV), Transformer + mutual inductance (Unit V).