2.7 : Superposition Theorem

The superposition principle is a fundamental concept stating that in a linear circuit, the voltage across (or current through) an element can be determined by summing the individual contributions of each independent source acting in isolation. When dealing with linear circuits containing multiple independent sources, this principle serves as a valuable tool for analysis. To apply the superposition principle effectively, one should focus on a single independent source at a time while deactivating all others. This approach yields the output (voltage or current) resulting from the active source.

The cumulative effect of all active sources can then be determined by algebraically adding their individual contributions. This simplifies the circuit analysis process. Notably, dependent sources remain unaffected as they are governed by circuit variables. It is worth noting that utilizing the superposition principle can lead to increased analytical effort. For example, when dealing with a circuit featuring three independent sources, one must analyze three separate, simplified circuits, each representing the contribution of an individual source. Despite this potential drawback, the superposition principle remains a valuable technique for simplifying complex circuits by replacing voltage sources with short circuits and current sources with open circuits.