Norton's Theorem Calculator

Norton's Theorem lets electrical engineers reduce any linear circuit to a simple equivalent — a current source in parallel with a resistance — making load analysis much faster. Enter your Thévenin Voltage (Vth), Thévenin/Norton Resistance (Rth), and Load Resistance (RL) into the Norton's Theorem Calculator to get the Norton Current (In). Secondary outputs include Norton Resistance (Rn), Load Current (IL), and Load Voltage (VL).

V

Open circuit voltage of the equivalent circuit

Ω

Equivalent resistance seen from load terminals

Ω

Resistance of the load connected to the circuit

Results

Norton Current (In)

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Norton Resistance (Rn)

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Load Current (IL)

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Load Voltage (VL)

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Frequently Asked Questions

What is Norton's Theorem?

Norton's theorem states that any linear circuit with voltage sources, current sources, and resistors can be simplified to an equivalent circuit consisting of a single current source in parallel with a single resistor. This simplification makes complex circuit analysis much easier.

How do you calculate Norton current?

Norton current (In) is calculated by dividing the Thévenin voltage by the Thévenin resistance: In = Vth / Rth. It represents the short-circuit current that would flow if the load terminals were connected together.

What is the relationship between Norton and Thévenin circuits?

Norton and Thévenin circuits are equivalent representations of the same circuit. The Norton resistance equals the Thévenin resistance, and the Norton current equals the Thévenin voltage divided by the Thévenin resistance.

How do you find the load current using Norton's theorem?

The load current is calculated using current division: IL = In × (Rn / (Rn + RL)), where In is Norton current, Rn is Norton resistance, and RL is load resistance. This formula shows how the Norton current divides between the Norton resistance and load resistance.

When should you use Norton's theorem instead of other circuit analysis methods?

Norton's theorem is particularly useful when analyzing circuits with current sources or when you need to find the current through different load resistances. It's also helpful when the circuit analysis involves parallel combinations of components.

What are the limitations of Norton's theorem?

Norton's theorem only applies to linear circuits containing linear components like resistors, voltage sources, and current sources. It cannot be used with non-linear elements such as diodes, transistors, or other semiconductor devices.

How do you determine Norton resistance?

Norton resistance is found by turning off all independent sources (replacing voltage sources with short circuits and current sources with open circuits) and calculating the equivalent resistance seen from the load terminals. This value is identical to the Thévenin resistance.