# Kirchhoff’s Voltage Law Formula

Kirchhoff’s voltage law or KVL formula relates the behavior of voltage in a loop. A loop is a circular path formed by the combination of resistors.

Statement: The sum of voltage rise in a closed loop is equal to the sum of voltage drop in that loop. The mathematical equation which relates the KVL:

∑V

_{rise}= ∑V_{drop}Let’s consider the closed loop circuit with three resistors and a voltage source.

Example: A 5 V input source powers three series resistors. The voltage drop across first and third resistors is 2 volts respectively. Find the voltage across the second resistor.

∑Voltage_{rise} = ∑Voltage_{drop}

V_{in }= V_{1 }+ V_{2} + V_{3}

5 V = 2 V + V_{2} + 2 V

V_{2} = 5 V – 2 V – 2 V

V_{2} = 1 V