Kirchhoff's circuit laws

Kirchhoff's first law, also known as Kirchoff's current law (KCL), states that at any node of the circuit, the sum of the currents flowing into the node is equal to the sum of current flowing out of the node.

Kirchhoff's second law, also known as Kirchhoff's voltage law (KVL), states that the sum of the voltage in a closed loop is always equal to zero.