Kirchhoff's laws [for Gustav R. Kirchhoff], pair of laws stating general restrictions on the current and voltage in an electric circuit. The first of these states that at any given instant the sum of the voltages around any closed path, or loop, in the network is zero. The second states that at any junction of paths, or node, in a network the sum of the currents arriving at any instant is equal to the sum of the currents flowing away.