根据基尔霍夫定律：节点上∑i=0和回路中∑u=0这两个公式，无论是在正旋稳态下还是在暂稳态电路中表达网络变量间的关系时都只取决于网络的布局即节点和支路的相互关系，而与支路的特性即支路由那些元件组成及其参数的量值都没有关系。因此当我们根据网络来建立节点电流方程及回路电压方程时，无须画出电路元件。这种节点与支路相互关系以表示电路结构的图，称为网络的图。在网络的图中，为建立KCL、KVL方程，取支路电压、支路电流关联参考方向，在图中的支路上标明。-According to Kirchhoff s Law: the nodes Σi = 0 and the loop Σu = 0 these two formulas, whether in the rotation is under steady-state or in the temporary steady-state expression of the circuit network, when the relationship between variables only depend on that is, the layout of network nodes and the relationship between the slip road, and with the slip characteristics of that slip by those components and their parameters are not related to money. So when we come to the establishment of the network node current equation and voltage loop equation, there is no need to draw circuit elements. Such nodes and the relationship between the slip to show the structure of the circuit diagram, known as the network plans. In the network map for the establishment of KCL, KVL equations, take the slip voltage, branch current associated reference direction of the branch in the figure marked on the road.