In a considered point of a circuit the algebraic sum of the currents flowing into a junction (or branch point) is zero. In the circuit below the currents flowing to the point are positive and the current flowing from the point are negative.
Formula 1
I1 + I2 + I3 + I4 + I5 = 0
Where:
I1, I2, I3, I4, I5 are the currents flowing to the junction P in amperes (A)
P is the junction point or branch point.
Note:
For the circuit given as example we can write:
I1 – I2 + I3 – I4 + I5 = 0
