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**CIRCUIT ANALYSIS AND TECHNIQUES**

Kirchoff's Current Law

The sum of currents flowing into the common point (a
node) at any instant is just equal to the sum of the currents flowing out.

The arrows define the reference direction for positive
current where current is defined by the motion of positive changes. The quantity
**i**, specifies the magnitude of the current and its algebraic sign with respect
to the reference direction.

By Kirchoff's current law, the algebraic sum of the
currents into a node **Σ****i**
at any instant is zero.

Σi = 0 = i1 +
i2 - i3 + i4