Superposition Theorem USEFUL FOR SOLVING LINEAR BILATERAL CIRCUITS

SUPERPOSITION THEOREM FOR ELECTRICAL CIRCUITS

1. Prepared by Dr. Sudheer Electrical Science –I Lecture 11 Superposition Theorem T1(4.5)

2. Prepared by Dr. Sudheer Electrical Circuit Theorems Superposition Theorem Thevenin's Theorem Norton's Theorem Maximum Power Transfer

3. Prepared by Dr. Sudheer Electrical Circuit Theorems Superposition Theorem: The Superposition theorem states that in any network containing more than one source , the current in, or the voltage across , any branch can be found by considering each source separately and adding their effects: omitted sources of e.m.f . are replaced by resistances equal to their internal resistances . Superposition theorem is applicable to linear circuits only and linear quantities only. Ex:- Superposition theorem is applicable to calculate current and voltage but not Power in any branch ( since it is a non-Linear quantity: P =I 2 R ). The superposition states that the voltage across (or the current through) an element in a linear circuit is the algebraic sum of the voltages across (or currents through) that element due to each independent source acting alone.

4. Prepared by Dr. Sudheer Not Considered sources/ Replacing with internal resistances Current source: We replace it by a current source where Voltage source: We replace it by a voltage source where An short-circuit i An open-circuit

5. Prepared by Dr. Sudheer Steps for Applying the Superposition Theorem Consider one independent source and replace all other independent sources with their internal resistances . Find the voltage or current in a branch due to the active source only. Repeat step 1 for each of the other independent sources. Find the total voltage or current in a branch is calculated by algebraically sum of all voltage or current obtained in steps 1 & 2.

6. Prepared by Dr. Sudheer Calculate current using Superposition Theorem Replacing the voltage sources with Their internal resistances

7. Prepared by Dr. Sudheer Circuit1 Circuit2

8. Prepared by Dr. Sudheer Calculate i using Superposition Theorem

9. Prepared by Dr. Sudheer Considering 12 V alone

10. Prepared by Dr. Sudheer Considering 24 V alone

11. Prepared by Dr. Sudheer Considering 3A alone

12. Prepared by Dr. Sudheer Calculate i using Superposition Theorem