Kirchhoff Voltage Law (KVL)

Kirchhoff Voltage Law states that ''The algebraic sum of all voltages (source voltage and voltage drops) is equal to zero around a close path''.

Kirchhoff Voltage Law Circuit

In the above circuit R1, R2 and R3 are three resistors connected in series across a voltage source V. VI , V2 and V3 are voltage drops across resistors R1, R2 and R3 respectively. So according to Kirchhoff voltage law

V + ( -V1 ) + ( -V2 ) + ( -V3 ) = 0

V - V1 - V2 - V3 = 0

V = VI + V2 + V3

This is called KVL ( Kirchhoff Voltage Law) equation.

V = VI + V2 + V3

Applied voltage = sum of all voltage drops


The source voltage is equal to the sum of all voltage drops.