The sum of all the voltages around the loop is equal to zero. v1 + v2 + v3 + v4 = 0
This law is also called Kirchhoff's second law, Kirchhoff's loop (or mesh) rule, and Kirchhoff's second rule.
The directed sum of the electrical potential differences around any closed circuit must be zero.
KVL may also be stated as " the algebraic sum of various potential drops across an electrical circuit is equal to the electromotive force acting on the circuit"