Definition: it c***ists of a layer of insulating dielectric between two metal electrodes. When a voltage is applied between the two metal electrodes, the charge is stored on the electrode, so the capacitor is an energy storage element. Any of two conductors that are insulated and close to each other and form a capacitor. The parallel plate capacitor c***ists of the electrode plate and the dielectric of the capacitor [1]. Characteristics: 1. It has charge-discharge characteristics and the ability to prevent DC current from passing through, allowing AC current to pass through. 2. During charging and discharging, the charge on the bipolar plate accumulates, that is, the voltage is set up, therefore, the voltage on the capacitor can not be abrupt. Capacitor charging: two plates with the same amount of dissimilar charge, each plate with the absolute value of the charge is called capacitor charge.