Capacitor principle - the mystery of capacitor charging and discharging process

Guide: The times are advancing, technology is developing, telecommunications technology is changing with each passing day, and the demand for consumer electronic products is growing. The capacitor industry is also advancing rapidly. China has now become a global capacitor manufacturing country. Let us know that we are proud of this. Let's take a look at the capacitor principle.

1. Capacitor Principle - - Introduction

Capacitor, the English name is capacitor, abbreviated as C, is a passive device that stores energy in the form of electric field. It exists in almost all electronic circuits, and can be used for DC-connected AC, coupling, bypass, filtering, tuning, etc. Multiple roles.

2. Capacitor principle - - structure

A capacitor is an energy storage component consisting of two metal plates and an interlayer of insulating dielectric. The basic structure and symbols are shown in the figure below. Any two conductors that are very close together and insulated from each other form a capacitor. When a voltage is applied to the conductor, the capacitor begins to store charge.

3. Capacitor principle - - charging process

The charging process is the process of storing the charge by the capacitor. When the capacitor is connected to the DC power supply, the charge on the metal plate connected to the positive pole of the power supply will flow to the metal plate connected to the negative pole of the power supply under the action of the electric field force. The metal plate connected to the positive pole of the power supply loses its charge positively, and the metal plate connected to the negative pole of the power supply is negatively charged (the two metal plates have the same charge and opposite signs), and the capacitor starts to charge.

In the circuit, the movement of the charge forms a current. Due to the repulsion of the same charge, the current is maximal at the beginning of the charge movement, and then gradually decreases. The charge of the capacitor is minimal at the beginning of the charge movement, and is zero during the charge movement. The charge is gradually increased, and the voltage between the two metal plates is gradually increased. When it is increased to be equal to the power supply voltage, the charging is completed and the current is reduced to zero.

4. Capacitor principle - - Discharge process

The discharge process is the process in which the capacitor discharges the stored charge. When the charged capacitor is in a closed path with no power supply, the charge on the negatively charged metal plate will be positively charged under the action of the electric field force. The plate runs away, neutralizing the positive and negative charges, and the capacitor begins to discharge.

In the circuit, the movement of the charge forms a current. Due to the attraction of the opposite charge, the current is maximum at the beginning of the discharge process, and then gradually decreases. The charge of the capacitor is maximum at the beginning of the discharge process, and then gradually decreases. When the charge is reduced to zero, the discharge is completed and the current is reduced to zero.

Since no current flows through the capacitor after the capacitor is charged, the capacitor can function as a DC-blocking circuit. In a DC circuit, it can be regarded as an open circuit.