Steps to solve Thevenins Theorem:
Equivalent circuits developed by thevenin's theorem are frequently called as thevenin's equivalent circuits.
We may explain thevenin's theorem by applying it to a two-terminal network by using following steps :
Here by applying thevenin's theorem you shall learn to determine the thevenin's equivalent circuit across the terminals where load RL is connected.
Create open circuit among the terminals for this remove RL in which current is to be determined.
Find out the open circuit voltage (Vth) between the terminals. So, voltage across R3 = i R3
(Voltage across R2 shall be zero as no current is following through it because of open circuit)
i = E / (r + R1 + R3)
Vth = Voltage across R3 only = (E / (r + R1 + R3)R3
Find out the internal resistance of the equivalent circuit (Rth) after replacing all of the sources in the original circuit along resistances equal to their internal resistances. While the original sources are viewed as ideal sources, voltage sources are replaced by short circuit and current sources are replaced by open circuit. After this total resistance among the terminals is calculate or measured.
Rth =( (r + R1 ) . R3 / r + R + R3 )+ R2
Replace the overall network by the Vth and Rth across the terminals (in which Rth is in series with Vth) or built thevenin's equivalent circuit across the terminals.
Connect load resistance RL back to its terminals from where it was eliminated.
Find out the current flowing through the load RL.
I = Vth / (Rth + RL)