通过简易的数学方法，比较直观地解析描述了RC 电路在周期为T、幅值为Um 和占空比为δ 的方波电压u 激励下的电容器C 上的响应电压uc 的变化情况，得出uc 在u 的上升沿和下降沿上的值将分别单调连续地收敛于Um (1-A1 )A2 / (1-A1 A2 )和Um(1-A1 )/ (1-A1 A2 )，其中A1 = e-Tδ / (RC)和A2 = e-T(1-δ)/ (RC). 同时也对各参数之间的关系进行了分析探讨.所得结论不但有助于理解和分析方波激励下的一阶RC 暂态过程的实验现象，也有助于改善实验设计时对参数的选择.

When a square wave voltage u with the period T，the amplitude Um and the duty ratio δ is used as the excitation，it is deduced explicitly by a simple method that the values of the response，uc，the voltage across the capacitor，on the rising edge and falling edge will converge monotonically and continuously to Um(1-A1 )A2 / (1-A1 A2)and Um(1-A1 )/ (1-A1 A2 )，respectively (where A1 = e-Tδ / (RC)，A2 = e-T(1-δ)/ (RC)).Moreover，the relationships among the parameters are also discussed. The results are not only useful for understanding and analyzing the experimental phenomena of the first-order RC transient process under square wave excitation，but also helpful for improving the experimental design.