# Kirchoff's current law

**KCL (Kirchoff's Current Law)**reads:

Algebraic sum of electric currents flowing toward to a point or a branching of a circuit, equal to the current that out of the point.

Written by equation

Σ I = 0

See electric current branching scheme as in the circuit below

Currents toward to the point A marked as positive (+), the points are IA, IB and ID.

Currents out of the point A marked as negative (-), that is IC

The equation becomes:

IA + IB - IC + ID = 0

IA + IB + ID = IC

Example question:

In the circuit above, it is known that IA = 10 A, IB = 6 A, IC = 18 A. What ID current is given to the circuit?

completion:

IA + IB - IC + ID = 0

10 + 6-18 + ID = 0

ID = 18 - 16 = 2 A

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