Norton’s Theorem states that it is possible to simplify any linear circuit to an equal circuit with a solitary current source and equivalent parallel resistance associated with a load. The simplified circuit is called Norton Equivalent Circuit.
This theorem is said to be the alternative of the Thevenin Theorem. Norton’s Theorem expresses that it is conceivable to improve any straight circuit to an equal circuit with a solitary current source and identical equal obstruction associated with a heap. The disentangled circuit is known as the Norton Equivalent Circuit.
Procedure to find Norton Equivalent Circuit
In the above figure, there are two resistance R1 and R2. These two resistances are connected in series. Series combination which is comprised of R1 and R2 is connected across one voltage source of emf E with internal resistance Ri.
As you can see in the above image, one resistive branch of RL and another resistance R3 is connected across the resistance R2.
We have to calculate current induced through RL by using Norton Theorem.
Let’s remove RL from both terminals A and B. This terminal works as a short-circuited by zero resistance.
Now find out the short circuit current or Norton equivalent current IN through points A and B.
The equivalent resistance of the network is given by,
To calculate internal resistance or Norton equivalent resistance RN of the network under consideration, remove the branch between A and B and also replace the voltage source with its internal resistance. Now the equivalent resistance as viewed from open terminals A and B is N,
As per Norton Theorem, when resistance RL is reconnected across terminals A and B, the network works as a source of constant current IN with shunt connected internal resistance RN and this is Norton equivalent circuit.