Norton's Theorem

Norton's theorem states that any linear two-terminal circuit can be replaced by an equivalent circuit consisting of a single current source in parallel with a resistor.

To implement Norton's theorem, remove the load resistor from the two load terminals: the remaining network will be substituted by the Norton equivalent circuit as seen from these terminals.

Norton's resistance can be determined by setting all independent sources to zero. The equivalent or input resistance between the terminals is Norton's resistance.

To find Norton's current, return all sources to their original positions. Then, calculate Norton's current by finding the short-circuit current between the marked terminals.

Finally, replace the network with the Norton equivalent circuit and connect the load resistor again.

The source transformation technique can be used to convert between Norton and Thévenin equivalent circuits.

Open circuit voltage, short circuit current, and input or equivalent resistance must be known to determine the Thevenin or Norton equivalent circuit.

The close relationship between Norton's and Thévenin's theorems and Ohm's law helps solve complex electrical circuits.