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Type of Capacitors

With the rapid growth of electronic information technology, the updated speed of digital electronic products is getting faster and faster. The sales of consumer electronic products such as flat-panel TVs, notebook computers, digital cameras, and other products continue to grow, which drives the growth of the capacitor industry.

Aluminum Electrolytic Capacitors

A capacitor with a thin oxide film as the medium is wound by absorbent paper impregnated with paste electrolyte between two aluminum foils. Because the oxide film has unidirectional conductivity, the electrolytic capacitor has polarity. It has the following characteristics:

  1. Large capacity, able to withstand larger pulsating current.
  2. The capacity error is large, the leakage current is large, and the ordinary one is not suitable for application under high frequency and low temperature, and it is not suitable to use the frequency above 25KHz.
  3. Low-frequency bypass, signal coupling, power supply filtering.

Tantalum Electrolytic Capacitors

The sintered tantalum block is used as the positive electrode. The electrolyte uses solid manganese dioxide. The temperature characteristics, frequency characteristics, and reliability are better than ordinary electrolytic capacitors, especially leakage current is very small, the storage performance is good, the life is long, the capacity error is small, The volume is small, and the maximum capacitor voltage product can be obtained per unit volume. It has poor tolerance to pulsating current. If it is damaged, it generally shows a short-circuit state and is often used in small parts.

Self-healing Shunt Capacitor

The structure is similar to that of paper capacitors, but low-loss materials such as polyester and script vinyl are used as the medium. Features are as follows:

  1. Good frequency characteristics and low dielectric loss.
  2. Can not be made into a large capacity, poor heat resistance.
  3. Filter, integration, oscillation, timing circuit. Ceramic dielectric capacitors, through-core or pillar structure ceramic dielectric capacitors, one of its electrodes is a mounting screw. The lead inductance is extremely small, the frequency characteristic is good, the dielectric loss is small, and it has a temperature compensation function.
  4. Can not be made into a large capacity, vibration will cause capacity changes.
  5. Suitable for high-frequency bypass.

Ceramic Capacitor:

A high-dielectric constant capacitor ceramic is extruded into a round tube, a wafer or disc is used as the medium, and silver is plated on the ceramic by firing and infiltration as a click. It is divided into high-frequency porcelain and low-frequency porcelain. Capacitors with positive capacitance temperature coefficients are used in high-stability oscillating circuits as loop capacitors and pad capacitors.

Low-frequency ceramic capacitors are limited to bypass or DC blocking in circuits with lower operating frequencies, or occasions where stability and loss are not high. Such capacitors are not suitable for use in pulse circuits because they are easily broken down by pulse voltage.

High-frequency Ceramic Capacitor

Mica capacitors used in high-frequency circuits can be divided into foil type and silver type in terms of structure. The silver electrode is formed by directly plating a silver layer on the mica sheet by vacuum evaporation or firing. Because the air gap is eliminated, the temperature coefficient is greatly reduced, and the capacitance stability is higher than that of the foil type. The frequency characteristic is good, the electric charge value is high, the temperature coefficient is small, it can not be made into a large capacity. It is widely used in high-frequency appliances and can be used as a standard capacitor.