Parts of Transformer - Electrical Diary

 What is Thevenin's Theorem?

Thevenin's theorem is a circuit theory that states any complex circuit or network can be reduced to a simple network that has a voltage source (Called Thevenin's Voltage) connected in series with total circuit equivalent resistance (Called Thevenin's Resistance) along with Load resistance.

By following the given step we can apply Thevenin's theorem 

• First Remove the Load Resistance from the Circuit.
• Calculate Open terminal Voltage Across Load terminal and called it V_th.
• Remove all Current Sources and Open the Terminal of the Current Source.
• Short the Voltage Source by its Internal Resistance
• Calculate The Circuit Total resistance across the Load terminal and called it R_th.
• Now redraw the circuit that consists of calculated Voltage(V_th) in series with Calculated Resistance(R_th).
• Connect the Load Across in series with the circuit.

Now we will take an Example and Solve it by using Thevenin's Theorem

Example:-
Solve the circuit given below and find the Current Flowing through the given circuit below

Step - Remove the load and short the Voltage source by its internal resistance

after removing load and short the battery by its internal resistance it will look like

from the above circuit it is clear that

Resistor  R₁  and R₂ are parallel and these two are in series  R₃with the Resistance of the circuit across terminal AB

 R_e=  R₁|| R₂ + R₃

 R_e= (100/2) + 100 = 50 +100 = 150Ω

R_e= 150Ω this is called Thevenin's equivalent Resistance (R_th)

Step - 2 Calculate the Open terminal Voltage across AB

Let V is voltage Across Terminal AB then 

By Voltage division Rule

 

Now Draw Thevenin's Equivalent Circuit like this

Let I is load current flowing through the load then 

Current Flowing through Load I = 0.2A