Superposition theorem

Objective

Show that the node voltage with both sources equals the sum of the voltages caused by each source alone.

Procedure

1. Run: note V(X) with both sources.
2. Set the 5 V source to 0 V, run, note V(X). Then restore it and set the 10 V source to 0 V.
3. Add the two partial answers.

Theory

In a linear circuit V = V(source 1 alone) + V(source 2 alone). Here the node X between R1, R2 and R3 is solved three times: both sources, then each with the other set to 0 V.

Questions to answer

1. Why does superposition fail for power?

Components used

2 × Battery / DC source, 3 × Resistor 220 ohm 1/4W

About the model

Ideal wires; component models as listed in the catalogue (no parasitics, no temperature drift). Built without a breadboard so the schematic stays readable.

More Basic Electrical Lab experiments

• Thevenin's theorem
• Norton's theorem
• Maximum power transfer
• Wheatstone bridge
• RL circuit time constant