Norton's Theorem is a principle in electrical circuit analysis that simplifies the study of complex linear circuits. It states that any linear electrical network with voltage and current sources and resistances can be replaced by an equivalent circuit consisting of a single current source, called the Norton current (I_N), in parallel with a single resistor, known as the Norton resistance (R_N). The Norton current is the short-circuit current that would flow through the terminals of the original circuit if they were shorted together, and the Norton resistance is the equivalent resistance of the circuit when all independent sources are deactivated (voltage sources shorted and current sources opened). This theorem is particularly useful for analyzing circuits with multiple sources and resistors, as it reduces the network to a simpler form, making it easier to calculate currents, voltages, or power delivered to a load. Norton's Theorem is closely related to Thevenin's Theorem, and the two are often used interchangeably depending on whether a current-source (Norton) or voltage-source (Thevenin) model is more convenient for the analysis.
