A capacitor is a device that holds an electric charge. Capacitor is one of the electronic components used in a large number of electronic equipment, widely used in the circuit of the direct alternating, coupling, bypass, filtering, tuning loop, energy conversion, control and other aspects. What are the commonly used capacitor classifications?

First, aluminum electrolytic capacitor

A capacitor made of absorbent paper impregnated with a paste electrolyte wrapped between two aluminum foils, with a thin oxide film as the medium. Because of the unidirectional conductive nature of the oxide film, the electrolytic capacitor has polarity.

Large capacity, can withstand large pulsating current.

Large capacity error, large leakage current; Ordinary is not suitable for application at high frequency and low temperature, and is not suitable for use at frequencies above 25kHz.

Low frequency bypass, signal coupling, power filtering.

Two, tantalum electrolytic capacitor

Sintered tantalum block was used as the positive electrode and solid manganese dioxide was used as the electrolyte.

Temperature characteristics, frequency characteristics and reliability are better than ordinary electrolytical capacitors, especially the leakage current is very small, good storage, long life, small capacity error, and small size, unit volume can be obtained under the maximum capacitor voltage product.

Poor tolerance to pulsating current, if damaged, it is easy to short circuit.

Ultra-small highly reliable parts.

Three, monolithic capacitor (multilayer ceramic capacitor)

A number of ceramic film billet coated with electrode paddle material, laminated after a wound into an indivisible whole, and then coated with resin outside

A new type of capacitor with small volume, large capacity, high reliability and high temperature resistance, and a low frequency monolithic capacitor with high dielectric constant also has stable performance, small volume and high Q value

Large capacity error

Noise bypass, filter, integral, oscillating circuit paper capacitor

Generally, two aluminum foams are used as electrodes, and the capacitor paper with a thickness of 0.008 ~ 0.012mm is separated and overlapped.

The manufacturing process is simple, the price is cheap, and a large electric capacity can be obtained

Four, ceramic capacitors

A high dielectric constant capacitor ceramic (barium titanate titanium oxide) is extruded into a tube, wafer or disk as the medium, and silver is plated on the ceramic as the electrode by burn-in method. It is divided into two kinds of high frequency porcelain and low frequency porcelain.

A capacitor with a small positive capacitance temperature coefficient, used as a loop capacitor and a pad capacitor in highly stable oscillation circuits.

Low FREQUENCY PORCELAIN DIELECTRIC CAPACITORS ARE limited to be used as bypass or DC isolation in low operating frequency circuits, or in situations where stability and loss requirements are not high (including high frequency). Such capacitors are not suitable for use in pulsed circuits because they are prone to breakdown by pulsed voltages.

Fifth, high frequency porcelain dielectric container

Suitable for high frequency circuit mica capacitor

In terms of structure, it can be divided into foil type and silver type. The silver electrode is directly plated on the mica by vacuum evaporation method or burning method. Because the air gap is eliminated, the temperature coefficient is greatly reduced, and the capacitance stability is higher than that of the foil type.

Good frequency characteristics, high Q value and small temperature coefficient

Can't make a large capacity

Widely used in high frequency electrical appliances, and can be used as a standard capacitor glass glaze capacitor

It is made by spraying a special mixture with a concentration suitable for spraying into a film, and then the medium is sintered with a silver layer electrode to form a "monolith" structure

Performance comparable to mica capacitor, can withstand a variety of climatic environments, generally can work at 200℃ or higher temperature, rated operating voltage up to 500V, loss tgδ0.0005 ~ 0.008

Six, fixed capacitor

Fixed capacitor detection method

A. Detection of small capacitors below 10pF Because the fixed capacitor capacity below 10pF is too small, measuring with a multimeter can only qualitatively check whether there is leakage, internal short circuit or breakdown. When measuring, the multimeter R×10k block can be selected, and the two pins of the capacitor can be arbitrarily connected with the two watch pens, and the resistance value should be infinite. If the resistance value is measured (the pointer swings to the right) is zero, it means that the capacitor is damaged by leakage or internal breakdown.

B. Detect whether the fixed capacitor of 10PF ~ 001μF has charging phenomenon, and then judge its quality. R×1k block is selected as the multimeter. The β values of both triodes are above 100, and the penetration current should be small. Can choose 3DG6 and other types of silicon triode composite tube. The red and black stylus of the multimeter are connected to the emitter e and collector c of the compound tube, respectively. Because of the compound triode amplification effect, the measured capacitor charge and discharge process to be amplified, so that the multimeter pointer swing amplitude is increased, so as to facilitate observation.

The above is the understanding of the classification and use of the common capacitors we use, only for reference.