Thevenin's Theorem

Related concepts: Superposition

Thevenin’s theorem is usually used to find the current through a resistor load.

It involves the conversion of a linear circuit into a Thevenin circuit—a circuit composed of a Thevenin voltage and resistor—which is then combined back with the resistor load.

Its purpose is to make it easier to find the load resistor’s current

$$I_{R_L}=\frac{V_{TH}}{R_{TH}+R_L}$$

Thevenin’s Resistance

To find the Thevenin resistance:

1. Remove load resistor and current sources
2. Short the voltage sources
3. The combination of remaining resistance is the Thevenin’s resistance

Thevenin’s Voltage

To find Thevenin voltage:

1. Remove the resistor load
2. Find the voltage across the open terminals

Sources

1. Thevenin’s theorem
2. Thevenin’s theorem example 1
3. Thevenin’s theorem example 2