电容器是储存电荷和电能的电子元件,是电路中被广泛应用的一种基本元件,若把一个已充电的电容器的两个极用导线短路而放电,则可见到放电火花,放电火花的能量是由充了电的电容器储存的电场能转化来的。那么,如何计算一个电势差为U、电容为C的电容器它所储存的电场能呢? 这可以从电容器带电的过程来分析。 如图1,可以等效地认为,电容器的带电过程就是 A capacitor is an electronic component that stores electric charge and electric energy. It is a basic component that is widely used in electric circuits. If the two poles of a charged capacitor are short-circuited and discharged by a wire, discharge sparks can be seen. The energy of the discharge spark is The electric field stored by the charged capacitor can be converted. So, how to calculate the electric field energy of a capacitor with a potential difference of U and a capacitance of C? This can be analyzed from the process of capacitor charging. As shown in Figure 1, it can be considered equivalently that the charging process of a capacitor is