A capacitor is an energy storage component composed of two metal plates and an insulating dielectric layer sandwiched between them. Any two very close and insulated conductors will form a capacitor. When a voltage is applied to a conductor, the capacitor begins to store charge.
Capacitor charging process
The charging process is the process of storing electric charge in a capacitor. When a capacitor is connected to a DC power source, the charge on the metal plate connected to the positive pole of the power source will move towards the metal plate connected to the negative pole of the power source under the action of electric field force, causing the metal plate connected to the positive pole of the power source to lose its charge and become positively charged, while the metal plate connected to the negative pole of the power source becomes negatively charged (the charge size of the two metal plates is equal, the sign is opposite), and the capacitor begins to charge.
In a circuit, the movement of charges forms a current. Due to the repulsion of same-sex charges, the current reaches its maximum at the beginning of charge movement and gradually decreases; At the beginning of charge movement, the minimum charge of the capacitor is zero. During the process of charge movement, the amount of charge gradually increases, and the voltage between the two metal plates gradually increases. When it increases to equal the power supply voltage, the current decreases to zero after charging.
Discharge process of capacitors
The discharge process is the process by which a capacitor releases stored charges. When the charged capacitor is located in a closed channel without power supply, the charge on the negative metal plate will move towards the positive metal plate under the action of electric field force, neutralizing the positive and negative charges, and the capacitor begins to discharge.
In a circuit, the movement of charges forms a current. Due to the attraction of opposite sex charges, the current is at its maximum at the beginning of the discharge process and gradually decreases; At the beginning of the discharge process, the capacitance of the capacitor is at its maximum and then gradually decreases. When the charge decreases to zero, the current decreases to zero after discharge.
Since there is no current flowing through the circuit after the capacitor is charged, the capacitor can act as a barrier against direct current. In a direct current circuit, it can be considered an open circuit.
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