由正弦电路的阻抗引发的思考

以容抗为例回顾了电抗的定义与实质,指出了容抗与电阻不同,容抗是电容的电压与电流的有效值（或幅值）之比,而不是电压与电流的瞬时值之比。文章着重指出了在激励频率为定值时,给定电容的容抗为常数,而其u（t）／i（t）却是时间的正切函数。该文指出了电阻与电抗、阻抗的区别,对正确理解和使用阻抗有帮助。

To Take Some Thinking by Impedance of Sinusoidal Circuit

This article reviewed the definition and the essence of the reactance by taking the capactive reactance for example.It points out the differences between the capacitive reactance and the resistance.Precisely,the capacitive reactance is the ratio of voltage's effective value(or amplitude) to current's value rather than their instantaneous values.This article also stresses that "u(t)/i(t)" is the tangent function of the time if capacitive reactance of the capcitance is a constant when assuming the frequency of the excitation is not variable,so showing us the differences to the resistance.This article offeres some help about how to make a sound understanding of them and correct using them as well.