Thévenin

Thévenin's theorem is a fundamental concept in electrical circuit analysis. It states that any linear electrical network with voltage sources and resistors can be replaced by an equivalent circuit consisting of a single voltage source and a single series resistor. This equivalent circuit is known as the Thévenin equivalent.

The voltage source of the Thévenin equivalent circuit is called the Thévenin voltage, often denoted as Vth. It represents the open-circuit voltage across the terminals of the original network. The series resistor is called the Thévenin resistance, denoted as Rth. It is calculated by deactivating all independent sources in the original network (voltage sources become short circuits and current sources become open circuits) and then finding the equivalent resistance seen from the terminals.

The primary utility of Thévenin's theorem lies in simplifying complex circuits. By reducing a complicated network to a simple equivalent, it makes it much easier to analyze the behavior of a load connected to those terminals. This is particularly useful when analyzing the response of a circuit to various loads without having to re-analyze the entire network each time. The theorem is applicable to linear circuits, meaning circuits where the relationship between voltage and current is linear, typically composed of resistors, independent and dependent voltage and current sources.