Kirchhoff's Current Law

\sum I_{in} = \sum I_{out}

Sum of currents at a node is zero.

Variables

ΣI_in

Current in

Current entering node

ΣI_out

Current out

Current leaving node

Conservation of charge at junction.

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Electricity & Magnetism formulas, under Electric Circuits, alongside Electric Power, Electric Current, Resistance, Resistors in Series and Resistors in Parallel.
In the electricity & magnetism list it comes after Kirchhoff's Voltage Law and before Capacitance.
Electricity & Magnetism formula sheet, one of 48 formulas printed with symbol keys and SI units.
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What is the Kirchhoff's Current Law formula?

Kirchhoff's Current Law is written ΣI_in = ΣI_out. Sum of currents at a node is zero. It belongs to Electricity & Magnetism, under Electric Circuits.

What are the units in ΣI_in = ΣI_out?

In SI units, ΣI_i n is current in, measured in A; ΣI_o ut is current out, measured in A.

How is the Kirchhoff's Current Law formula derived?

Conservation of charge at junction. The result is ΣI_in = ΣI_out.