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Kirchhoff's current law

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Objective

Verify that the currents into a node sum to zero.

Procedure

  1. Run and read the three branch currents.
  2. Change R3: I1 and I3 change, but I1 = I2 + I3 always holds.

Theory

KCL: Σ I(in) = Σ I(out). The 12 V source feeds R1 into a node that splits through R2 and R3 to ground: I1 = I2 + I3.

Questions to answer

  1. What happens to I2 when R3 changes?

Components used

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.

Open this experiment in the circuit simulator

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