Norton Equivalent Circuits

A Norton equivalent circuit replaces any two-terminal linear network with a constant current source in parallel with an impedance. This simplified representation maintains the same electrical behavior as the original circuit. Norton's theorem is beneficial for analyzing and designing systems containing complex AC circuits by breaking them into smaller, manageable sections.

To find Norton impedance, replace all sources with their internal impedances and calculate the equivalent impedance of the resulting circuit. The Norton impedance equals the Thévenin impedance. This value represents the parallel impedance component in the Norton equivalent circuit and is essential for determining circuit behavior.

The Norton current is calculated using the relationship between Thévenin voltage and Thévenin impedance. The Thévenin voltage is determined by multiplying the source current by the Thévenin impedance. By substituting these values into the relationship, you can determine the Norton current flowing through the circuit.

Norton's theorem simplifies complex AC circuits by allowing you to replace each stage or section with its Norton equivalent circuit. This breaks down complicated networks into simpler, equivalent components consisting of a current source and parallel impedance. The overall system analysis becomes more manageable and easier to solve.

Both Norton and Thévenin impedances are calculated using the same method: replacing sources with their internal impedances and finding the equivalent impedance. Since both theorems describe the same two-terminal network from different perspectives—current source versus voltage source—their impedance values are identical.

To determine Norton current, first place sources back into the circuit after finding Norton impedance. Analyze the open-circuit voltage, which is the Thévenin voltage. Calculate the product of source current and Thévenin impedance, then use the relationship between Norton current, Thévenin voltage, and impedance to find the Norton current value.

The Norton equivalent replaces a complex two-terminal linear network with a simpler parallel configuration of a constant current source and impedance. This maintains electrical equivalence at the terminals while providing a more straightforward representation for analysis. The load impedance experiences the same voltage drop in both configurations.