Capacitor classification principle: main types and types, characteristics and descriptions

The capacitor is presented in the form of an electronic component, consisting of 2 plates, between which there is a dielectric. The classification of capacitors is based on the material for the manufacture of plates, the type of dielectric and other criteria. The part in question is used in radio and electronic devices for the purpose of performing various tasks.

Types of products

The devices help determine the optimal oscillation frequency on the generators. Experts in the field of electronics know what capacitors are. The standard classification is based on a dielectric with its own characteristics.

Taking this criterion into account, the following models are distinguished:

• vacuum;
• with solid, gas and liquid dielectrics;
• electrolytic.

In terms of volume, variable, constant and trimming devices are distinguished. In the first models, capacitance changes due to voltage and temperature. Fixed capacitors have constant capacitance throughout their service life. Trimmer counterparts can change the capacity. They are used for one-time or periodic adjustment of the circuit.

Taking into account the scope of application, the following types of capacitors are distinguished:

• low volt;
• high voltage;
• pulse;
• starting (start the motor);
• overwhelming interference.

Models from other classes can be found less often in practice.

In electronics, users and professionals alike can come across a paper device. This type of capacitor is used in low and high frequency circuits. The dielectric at its base is a special capacitor paper. The device has low mechanical strength. It is often mounted in a metal case, which serves as the mechanical basis of the entire structure.

The metal-paper analogue has high hermetic characteristics and significant specific capacity. At the same time, it differs from other types by high-quality electrical insulation. It uses a metal vacuum deposited on the dielectric itself.

Electrolytic devices are characterized by the presence of a thin layer of metal oxide. It is formed electrochemically on the cover. Dry or liquid electrolyte is used as another cover.

The material used to create the metal electrode:

• tantalum;
• aluminum.

Experts understand the term "electrolyte" as an aluminum unit with a liquid cover. Most of the devices in this group are polarized.

When polarity is reversed, an irreversible chemical reaction occurs within the device. This leads to its destruction.

Specialists believe that the product will explode due to gas released inside it. Supercapacitors are also considered electrolytic capacitors. They are characterized by a high electrical capacity - several thousand Farads.

Aluminum and tantalum

For the production of the positive electrode, aluminum can be used, and for the dielectric, aluminum trioxide. A capacitor of this composition operates only at low frequency, while it has a large capacity, moderately low resistance and inductance.

Tantalum products are equipped with a tantalum metal electrode. The dielectric is tantalum pentoxide.

The capacitor has the following properties:

• increased resistance to external influences;
• compactness;
• slight leakage current.

In addition to standard products, modern solid-state capacitors can be found in the circuits. In them, the oxide film is replaced by a polymer dielectric. Such models are not bloated. They do not leak charge.

Due to its high physical properties, the part has a large pulse current, low resistance, and stable temperature. To find out what a polymer capacitor looks like, you can disassemble the filter from a switching power supply. The modern device often replaces the tantalum or electrolytic analogue installed in DC-DC converters.

Film devices

Products in which the dielectric is a plastic film in the form of polyester, polypropylene or polycarbonate are called film products. The electrodes are sprayed onto the film. In some models, they are made of rolled foil. Sometimes the foil is pressed together with the dielectric film. Polyphenylene sulfide is used from modern materials for the production of dielectric.

Film devices are characterized by the following properties:

• correct operation at high current;
• good tensile strength;
• small capacity;
• small leak;
• wide application in resonant circuits.

Some types of film have good temperature properties and high resistance to electrical breakdown.

Ceramic and air

For the manufacture of the device, special ceramic raw materials can be used, which have different properties, including high electrical permeability. Due to the latter characteristics, the device has small parameters. In terms of its capacity, it can compete with the electrolytic analogue. At the same time, the ceramic capacitor is capable of operating with different polarizations.

Due to the small parameters of the case, the device has a special marking. If air is used as the dielectric, the capacitor will work well at high frequency. Such models are used to configure devices.

Common parameters

When buying a capacitor on your own, special attention is paid to its technical characteristics. The main parameter is the capacity. If the value of the indicator does not exceed 9999 pF, there are no units of measurement on the diagram. If the capacitance exceeds the indicated figures, but not more than 9999 μF, the unit of measurement is indicated on the diagram.

Additionally, the nominal voltage is indicated: 5-1000 V and more. Experts advise buying a capacitor with a margin of rated voltage. Otherwise, dielectric breakdowns may occur. The device itself will fail. Additional parameters include operating temperature, current. On the modern market, you can buy capacitors with one and three phases. They are designed for indoor and outdoor installation.