The formula of four factors is given in analyzing first - order circuits , the initial value is extend as far as 0 _ value and it is unanimously agreed other theory of circuit analysis 摘要给出了直流激励下的一阶电路的四要素公式,将经典分析的起点延伸到0 _ ,使经典电路分析与现代电路分析的起点一致,统一了动态分析理论。