KCL equation, that is, Kirchhoff's first law, also known as Kirchhoff's current law, is the embodiment of current continuity in lumped parameter circuits, and its physical background is the axiom of charge conservation. Kirchhoff's current law is a law to determine the relationship between the currents of any node and each branch in the circuit, so it is also called the node current law.

KVL equation, also known as Kirchhoff's second law and Kirchhoff's voltage law, is the embodiment of the singularity of potential in lumped parameter circuits when the electric field is a potential field, and its physical background is the conservation of energy. Kirchhoff's voltage law is a law to determine the relationship between voltages in any circuit, so it is also called loop voltage law.

Kirchhoff's law is the basic electrical law for solving complex circuits. 19 in the 1940s, due to the rapid development of electrical technology, the circuit became more and more complicated. Some circuits are network-like, and there are some intersections (nodes) formed by three or more branches in the network.

This complex circuit can not be solved by series-parallel circuit formula. Gustav robert kirchhoff (1824 ~ 1887), who just graduated from the University of Konigsberg, Germany, was only 2 1 year old, and put forward it in his paper 1. This law can quickly solve any complex circuit, thus successfully solving this difficult problem that hinders the development of electrical technology. ?

Kirchhoff's law includes Kirchhoff's first law and Kirchhoff's second law, in which Kirchhoff's first law is Kirchhoff's current law, abbreviated as KCL；; Kirchhoff's second law is called Kirchhoff's voltage law, or KVL for short.