When the electric field strength increases, the storage capacity of charges also increases accordingly, and the amount representing the electric field strength is the electric field strength E of the capacitor. The smaller the distance between conductor plates, the greater the electric field strength. After the capacitor is connected to the power supply, the charge from the power supply flows into the capacitor. At the same time, an electric field is formed between the conductor plates, and the electric field strength continues to increase until it reaches the limit value of the capacitor, and no new charge enters the capacitor. When the charge of the capacitor is saturated, the electric field strength formed between the conductor plates reaches its maximum value, and the capacitor can store energy. When the amount of charge stored in the capacitor reaches its maximum value, the power supply is disconnected from the capacitor, while the previously stored charge can be maintained indefinitely. When the power supply is reconnected to the capacitor, the stored charge begins to be released.