Briefly analyze the characteristics and functions of capacitors

When it comes to capacitors, we all know that this is one of the most widely used and very important components in electronic product facilities. It is usually manufactured in series. In order to facilitate the choice of circuit designers, capacitors are arranged in series according to their working voltage and capacity. Therefore, capacitors are also known as general-purpose electronic components.

Capacitors work by storing a load in the electrodes and holding electrical energy (usually combined with an inductor) to form an LC oscillator circuit, the function of a capacitor is that the charge will move under an electric field, if there is a device between the wires, the charge will be moved Blocking, as charge builds up on the conductor, which results in the accumulation of charge.

Capacitors are one of the most commonly used electronic components in electronic devices. Therefore, it is widely used in locking, coupling, sliding, filtering, synchronizing circuits, power conversion and control circuits.

Characteristics and Functions of Capacitors

The structure of the capacitor is very simple. The two electrode plates face each other and are separated by an insulating material (called a dielectric) to form a capacitor. Different types of capacitors use different raw materials for their dielectrics.

The capacitance of a capacitor is determined by the size, shape, relative position of the two electrode plates that make it up, and the dielectric between them.

The function of a capacitor is to store charge or electrical energy. Utilize the characteristics of capacitors to charge, discharge, cut off direct current and pass alternating current, and are used in the circuit for AC coupling, filtering, decoupling, DC blocking, AC bypass, tuning, energy transfer, and oscillating circuits.

(1) In a DC circuit, when the voltage on the circuit is higher than the voltage at both ends of the capacitor, the capacitor is charged (when the capacitor is charged, there is current flow), until the voltage built on the capacitor is the same as the circuit's voltage. voltages are equal. At this point, the capacitor is "filled" (current will stop flowing when the capacitor is fully charged).

(2) If the voltage on the capacitor is higher than the voltage of the circuit, the generator discharges (when the generator discharges, the current flows in the other direction) until the voltage on the capacitor is equal to the voltage of the circuit ( When the capacitor discharge ends, the current will stop flowing).

When the capacitor is connected to the AC circuit, because the magnitude and direction of the voltage of the external circuit are 0, +, 0, -, 0... There has always been a round-trip alternating current flow. Therefore, the capacitor is like a special resistor to the alternating current, it can pass the alternating current.

It should be seen that the reason why the capacitor can pass alternating current is because the voltage of the external circuit is constantly changing, so that the capacitor can be charged and discharged alternately, not the insulating medium in which the current can really pass.