Kirchhoff's voltage law, also known as KVL, is a fundamental law in the field of electrical engineering. It states that the sum of all voltage drops in a closed loop circuit is equal to the total voltage applied to the circuit. KVL is often referred to as Kirchhoff's second law, with the first being Kirchhoff's current law (KCL). Other synonyms for KVL include Kirchhoff's loop law, Kirchhoff's mesh law, and Kirchhoff's second rule. These variations all refer to the same fundamental principle of the sum of voltage drops equaling the applied voltage in a closed loop circuit.