[Repost] Classification and characteristics of various capacitors

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[Repost] Classification and characteristics of various capacitors [Copy link]

Capacitors are commonly used electronic components in electronic equipment. The following is a brief introduction to the structure and characteristics of several commonly used capacitors for your reference.

1. Aluminum electrolytic capacitor:

It is made of an aluminum cylinder as the negative electrode, filled with liquid electrolyte, and a curved aluminum strip as the positive electrode. It also needs to be treated with DC voltage to form an oxide film on the positive electrode as a medium. Its characteristics are large capacity, but large leakage, poor stability, positive and negative polarity, suitable for power supply filtering or low-frequency circuits. When using, do not connect the positive and negative poles in reverse.

2. Tantalum-niobium electrolytic capacitor:

It uses metal tantalum or niobium as the positive electrode, dilute sulfuric acid and other liquid as the negative electrode, and the oxide film generated on the surface of tantalum or niobium as the medium. Its characteristics are: small size, large capacity, stable performance, long life. High insulation resistance. Good temperature performance, used in equipment with higher requirements.

3. Ceramic capacitor:

Ceramic is used as the medium. A silver layer is sprayed on both sides of the ceramic substrate, and then the silver film is fired to make the electrode. Its characteristics are: small size, good heat resistance, low loss, high insulation resistance, but small capacity, suitable for high-frequency circuits. Ferroelectric ceramic capacitors have a larger capacity, but larger losses and temperature coefficients, and are suitable for low-frequency circuits.

4. Mica capacitor:

Use metal foil or spray silver layer on mica sheet as electrode plate. After the electrode plate and mica are stacked layer by layer, they are die-cast in bakelite powder or sealed in epoxy resin. Its characteristics are: small dielectric loss and large insulation resistance. Small temperature coefficient, suitable for high-frequency circuits.

5. Film capacitor:

The structure is the same as that of paper dielectric capacitors, and the dielectric is polyester or polystyrene. Polyester film capacitors have a higher dielectric constant, small size, large capacity, and good stability, and are suitable for bypass capacitors. Polystyrene film capacitors have low dielectric loss and high insulation resistance, but a large temperature coefficient and can be used in high-frequency circuits.

6. Paper dielectric capacitors:

Two pieces of metal foil are used as electrodes, sandwiched in extremely thin capacitor paper, rolled into a cylindrical or flat cylindrical core, and then sealed in a metal shell or insulating material shell. Its characteristics are small size and large capacity. However, the inherent inductance and loss are relatively large, suitable for low-frequency circuits.

7. Metallized paper dielectric capacitor:

The structure is basically the same as that of paper dielectric capacitors. It is a layer of metal film on the capacitor paper instead of metal foil. It is small in size and large in capacity. It is generally used in low-frequency circuits.

8. Oil-immersed paper capacitors:

It is a paper capacitor immersed in specially treated oil, which can enhance its withstand voltage. Its characteristics are large capacitance and high withstand voltage, but large size. In addition, in practical applications, first, different types of capacitors should be selected according to different uses; second, the nominal capacity of the capacitor, allowable error, withstand voltage value, leakage resistance and other technical parameters should be considered; third, for electrolytic capacitors with positive and negative polarity, the positive and negative poles should not be connected in reverse during welding.

DestinyX

Hello, could you explain the equivalent model of capacitor in detail?