Thevenin's Theorem
To solving any problem by using Thevenin's theorem we will follow the steps as described below
A. Firstly we will eliminate the load resistor (The resistor we desire to calculate the unknown quantity that is current, voltage or power) from the circuit leaving behind an open circuit.
B. Determining the Vth at open terminals of the open circuit by any method.
C. Determining the Rth (The overall resistance in the Thevenin's circuit) by open circuiting all of current sources & short circuiting all of voltage sources.
D. After determining these two, re-inserting the load resistance RL in the circuit in series having Rth and considering the Vth like a battery in series along these two resistances.