What are the capacitors? Types of capacitors, their characteristics
Many people are interested in whether capacitors have types.There are many capacitors in electronics. Indicators such as capacity, operating voltage and tolerance are basic. No less important is the type of dielectric from which they consist. In this article, we will consider in more detail which types of capacitors are in the form of a dielectric.
Classification of capacitors
Capacitors are commoncomponents in radio electronics. They are classified by a set of indicators. It is important to know which models, depending on the nature of the change in the value, represent different capacitors. Types of capacitors:
- Devices with a constant capacity.
- Devices with a variable type of capacity.
- Constructing models.
The type of dielectric of the capacitor can be different:
- metal paper;
By the method of installation, these devices are designed for printed and mounted mounting. In this case, the types of SMD-capacitor case are:
- metal (aluminum).
It should be noted that instruments made of ceramics, films andnon-polar species do not have a marking. The indicator of their capacity varies from 1 pF to 10 mF. Electrolyte types are in the form of barrels in an aluminum casing and are marked.
The tantalum type is made in cases of rectangular shape. Such devices come in different sizes and colors: black, yellow and orange. They also have code marking.
Electrolytic capacitors from aluminum
The basis of electrolytic capacitors fromaluminum are two thin stranded aluminum strips. Between them is the paper containing the electrolyte. The capacity indicator of this device is 0.1-100 000 uF. By the way, this is its main advantage over other species. The maximum voltage is 500 V.
The disadvantages include increased leakage current and a decrease in capacitance with increasing frequency. Therefore, in the boards, the ceramic is often used together with the electrolytic capacitor.
It should also be noted that this type is differentpolarity. This means that the output of the device with a minus sign is under negative voltage, in contrast to the opposite output. If you do not adhere to this rule, then most likely, the device will fail. Therefore, it is recommended to use it in circuits with the presence of a constant or pulsating current, but in no case is not variable.
Electrolytic capacitors: types and applications
Types of electrolytic capacitors are represented by a wide range. They are:
- polymeric radial;
- with low leakage current;
- standard configuration;
- with a wide range of temperatures;
- with the presence of hard output;
- low impedance.
Where are electrolytic capacitors used?Types of capacitors made of aluminum are used in various radio engineering devices, computer parts, peripheral devices such as printers, graphics devices and scanners. They are also used in construction equipment, industrial instruments for measurement, in the field of weapons and space.
There are also clay capacitors of the KM type. They are used:
- in industrial equipment;
- when creating instruments for measurement, which are distinguished by high-precision indicators;
- in radio electronics;
- in the sphere of the military industry.
Devices of this type are distinguished by a highlevel of stability. The basis of their functionality are the pulse modes in circuits with alternating and unchanging current. They are characterized by a high level of adhesion of the plates from the ceramic and a long service. This is ensured by a low value of the coefficient of capacitive temperature variability.
KM capacitors with small dimensions have a high capacitance value, reaching 2.2 μF. Change of its value in the range of operating temperature for this species is from 10 to 90%.
Types of ceramic capacitors of group H, asthe rule is used as adapters or blocking devices, etc. Modern clay devices are made by pressing under pressure into a complete block of the finest metallized ceramic plates.
A high level of strength of this material makes it possible to use thin blanks. As a result, the capacity of the capacitor, proportional to the volume index, increases sharply.
KM devices are of high cost. This is explained by the fact that in their manufacture precious metals and their alloys are used: Ag, Pl, Pd. Palladium is present in all models.
Capacitors based on ceramics
The disk model has a high level of capacity. Its value ranges from 1 pF to 220 nF, and the highest operating voltage should not be above 50 V.
The advantages of this type include:
- low current losses;
- small size;
- low induction rate;
- ability to function at high frequencies;
- high level of temperature stability of capacity;
- The possibility of working in circuits with a constant, variable and pulsating current.
The basis of the multilayer device consists of alternating thin layers of ceramics and metal.
This view is similar to a single-layer disc.But such devices have a high capacity. The maximum operating voltage on the housing of these devices is not indicated. As well as on a single-layer model, the voltage should not be higher than 50 V.
Devices operate in circuits with a constant, variable and pulsating current.
The advantage of high-performance ceramic capacitorsis their ability to function under a high voltage level. The range of the operating voltage ranges from 50 to 15000 V, and the capacitance value can range from 68 to 150 pF.
Can function in circuits with a constant, variable and pulsating current.
Modern tantalum devices are an independent subtype of the electrolytic species of aluminum. The basis of the capacitors is tantalum pentoxide.
Capacitors have a small indexvoltage and are used in case of need to use a device with a large capacity indicator, but in a small-sized case. This type has its own peculiarities:
- small size;
- the maximum operating voltage is up to 100 V;
- increased level of reliability with long use;
- low leakage current;
- wide range of operating temperatures;
- the capacitance index can range from 47 nF to 1000 uF;
- devices have a lower level of inductance and are used in high-frequency configurations.
The minus of this kind is concluded in a high sensitivity to an increase in the operating voltage.
It should be noted that, unlike the electrolytic form, a line on the body marks a positive terminal.
Types of buildings
Which varieties have tantalum capacitors? Types of capacitors from tantalum are allocated depending on the material of the body.
- SMD package.For the manufacture of housing devices that are used for surface mounting, the cathode is connected to the terminal by means of an epoxy resin with a silver filler content. The anode is welded to the electrode, and the stringer is cut off. After the device is formed, it is printed on it. It contains an indication of the nominal capacity of the voltage.
- When this type of housing is formedThe anode conductor must be welded to the anode itself, and then cut off from the stringer. In this case, the cathode terminal is soldered to the base of the capacitor. The condenser is then filled with epoxide and dried. As in the first case, it is labeled
Condensers of the first type are more reliable. But all types of tantalum capacitors are used:
- in mechanical engineering;
- computers and computers;
- equipment for television broadcasting;
- electrical household appliances;
- a variety of power supplies for motherboards, processors, etc.
Search for new solutions
To date, tantalum capacitorsare the most in demand. Modern manufacturers are in search of new methods to increase the level of strength of the product, optimize its technical characteristics, as well as a significant price reduction and unification of the production process.
For this purpose, they try to reduce the cost on the basis of constituent components. The subsequent robotization of the entire production process also contributes to a fall in the price of the product.
An important issue is the reduction of the device's housing while maintaining high technical parameters. Experiments have already been carried out on new types of enclosures in a reduced version.
Capacitors made of polyester
The capacity indicator of this type of device can range from 1 nF to 15 uF. The spectrum of the operating voltage is the index from 50 to 1500 V.
There are devices with different degrees of tolerance (permissible capacity deviation is 5%, 10% and 20%).
This species has a stable temperature, high level of capacity and low cost, which explains their wide application.
Capacitors with variable capacitance
Types of variable capacitors havea certain principle of work, which consists in the accumulation of charge on plates-electrodes, isolated through a dielectric. These plates differ mobility. They can move.
A moving plate is called a rotor, and a stationary plate is called a stator. If their positions change, both the intersection area and, as a consequence, the capacity indicator of the capacitor will change.
Condensers come with two types of dielectrics: air and solid.
In the first case, the role of the dielectric isordinary air. In the second case, ceramics, mica and other materials are used. To increase the capacity of the device, the stator and rotor plates are assembled into blocks fixed on a single axis.
Air-insulated type capacitorsThey are used in systems with constant capacity adjustment (for example, in radio tuning tuners). This type of device has a higher level of durability than ceramic.
The most common type are building capacitors. They belong to the variable type, but they have less wear resistance, since they are less regulated.
The types of capacitors of this category in the base contain metallized ceramics. Metal functions as an electrode, and ceramics acts as an insulator.