Advantages and disadvantages of four common capacitors are explained

1. Aluminum electrolytic capacitor (CD)

Structure: polar aluminum electrolytic capacitor is made by winding aluminum foil (positive pole) with oxide film and pad paper soaked with electrolyte together with laminated cathode (negative pole) foil. The outer package is tubular and vertical. And a blue or black plastic cover is provided outside the aluminum shell.

Advantages: large capacity range, ranging from 1 to 10,000 microns, rated operating voltage range from 6.3v to 450v.

Disadvantages: dielectric loss, large capacity error (maximum allowable deviation +100%, -20%) poor high temperature resistance, storage time is easy to fail.

Purpose: it is used for filtering, decoupling, signal coupling, time constant setting and dc isolation in dc power supply circuit or medium and low frequency circuit. Note: do not use in ac power circuits. The polarity cannot be reversed when the filter capacitor is used in dc power supply.

2 porcelain dielectric container (CC)

Structure: ceramic material is used as the medium, coated with a layer of metal (silver) film on the ceramic surface, and then sintered at high temperature as an electrode. Porcelain dielectric containers are divided into 1 type of dielectric (NPO, CCG); 2 types of dielectric (X7R, 2X1) and 3 types of dielectric (Y5V, 2F4) porcelain dielectric containers.

Features: type 1 porcelain dielectric container has the advantages of small temperature coefficient, high stability, low loss and high pressure resistance. The maximum capacity is not more than 1,000pf, commonly used CC1, CC2, CC18A, CC11, CCG series.

Purpose: mainly used in high frequency circuits.

Characteristics: two or three kinds of ceramic dielectric containers are characterized by high dielectric coefficient, large capacity (up to 0.47 microns), small volume, loss and insulation properties are different from those of the first kind.

Purpose: widely used in middle and low frequency circuits as isolation, coupling, bypass and filter capacitor use. Commonly used CT1, CT2, CT3 and other three series.

3 polyester capacitor (CL)

Structure: polyester capacitor is a non-polar capacitor with positive temperature coefficient (i.e., when the temperature increases, the capacitance increases) made of polarizable polyester film as the medium.

Advantages: high temperature resistance, high pressure resistance, moisture resistance, low price.

Purpose: generally used in medium and low frequency circuits. Commonly used models are CL11, CL21 series.

4 polystyrene capacitor (CB)

Structure: there are two types of foil type and metallized type.

Advantages: foil insulation resistance, small dielectric loss, stable capacity, high precision, but large volume, poor heat resistance; The metallized type has better moisture resistance and stability than the foil type, and can heal itself after breakdown, but the insulation resistance is low and the high-frequency characteristics are poor.

Purpose: generally used in medium and high frequency circuits.

Commonly used models are CB10, CB11 (non-sealing foil), CB14~16 (precision), CB24, CB25 (non-sealing metallization), CB80 (high-pressure), CB40 (sealing metallization) and other series.