5. Superposition

Superposition

The current in any given branch of a multiple-source circuit can be

found by determining the currents in that particular branch produced

by each source acting alone, with all other sources replaced by their

internal impedances. The total current in the given branch is the phasor

sum of the individual source currents in that branch.

The superposition principle 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.

Steps in Applying the Superposition

1.Turn off all independent sources except one.  Find the output (voltage or current) due to the active source.

2.Repeat step 1 for each of the other independent sources.

3.Find the total output by adding algebraically all of the results found in steps 1 & 2 above.

Example:

Note: In applying superposition in
this case, each source is
applied independently, and
the results are added to
obtain the solution.