Q2Basic Electrical Engineering

Thevenin's theorem is a foundational principle of circuit analysis that states any linear, bilateral, active electrical network consisting of multiple independent/dependent sources and multiple resistances can be rigorously replaced by a highly simplified, equivalent electrical circuit.

This exact equivalent circuit uniquely consists of a single independent voltage source, denoted formally as Thevenin Voltage ($V_{th}$), connected strictly in series with a single equivalent resistance, denoted as Thevenin Resistance ($R_{th}$).

Mathematically, $V_{th}$ is evaluated as the absolute open-circuit voltage precisely across the defined load terminals, while $R_{th}$ is the equivalent internal resistance measured looking completely back into the circuit when all independent sources are systematically deactivated (voltage sources shorted, current sources opened).