What is a capacitor and what is it for?

Explaining what a capacitor is, we must clearly represent the physical foundations of the work and design of this indispensable element of every serious electronic device.

A capacitor is an element of an electrical circuit consisting of two conductive plates, each of which contains an opposite electric charge. The plates are separated by a dielectric, which helps them maintain this charge.

There are several types of insulating materials used in capacitors, including ceramics, mica, tantalum and polystyrene. Widely used in the manufacture of capacitors are also insulators, such as air, paper and plastic. Each of these materials effectively prevents the capacitor from interfering with each other.

What is capacitor capacitance?

The concept of "capacitor capacitance" characterizes its ability to accumulate an electric charge. The unit of measurement of capacitance is Farad.

If the capacitor maintains a charge of 1 pendant at a potential difference between its 1 volt covers, then it has a capacitance of one Farad. In fact, this unit is too large for most practical applications. Typical capacitance values when using capacitors fall within the ranges of MF (10-3 F), microfarad (10-6 F) and picofarad (10-12 F).

What are the capacitors?

In order to understand what a capacitor is, it is necessary to consider the main types of this component, depending on the purpose, application conditions and the type of dielectric.

Electrolytic capacitors are used in circuits where high capacity is required. Most of these elements are polar. The usual materials for them are tantalum or aluminum. Aluminum electrolytic capacitors are much cheaper and have a wider application. Nevertheless, tantalum has a significantly greater volumetric efficiency and has excellent electrical characteristics.

Tantalum capacitors have a tantalum oxide as a dielectric. They are characterized by high reliability, good frequency characteristics, wide range of operating temperatures. They are widely used in electronic equipment, where a high level of capacity is required at small dimensions. Due to their advantages, they are produced in large quantities for the needs of the electronics industry.

The disadvantages of tantalum capacitors include sensitivity to current pulsations and overvoltages, and also the relative high cost of these products.

Power capacitors, as a rule, are used in high voltage systems. They are widely used to compensate for losses in power lines, as well as to improve the power factor in industrial electrical installations. Are made of high-quality metallized propylene film with the use of special impregnation with non-toxic insulating oil.

They can have the function of self-destruction of internal damages, which gives them additional reliability and prolongs the service life.

Ceramic capacitors have ceramics as a dielectric material. They feature high functionality in terms of operating voltage, reliability, low losses and low cost.

Their range of capacities varies from several picofarads to about 0.1 μF. Currently, they are one of the most widely used types of capacitors used in electronic equipment.

Silver mica condensers replaced the previously widespread mica elements. They have high stability, a sealed housing and a large capacity per unit volume.

The wide use of silver-mica condensers is hampered by their relative high cost.

In paper and metal capacitors, the plates are made of thin aluminum foil, and as a dielectric, special paper impregnated with a solid (molten) or liquid dielectric is used. They are used in low-frequency circuits of radio devices at high currents. They differ in relative cheapness.

What is the use of a capacitor?

There are a number of examples of the use of capacitors for a wide variety of purposes. In particular, they are widely used for storing analog signals and digital data. Capacitors of variable capacity are used in telecommunications to regulate the frequency and configuration of telecommunications equipment.

A typical example of their use is the use in power supplies. There, these elements perform the function of smoothing (filtering) the rectified voltage at the output of these devices. They can also be used in voltage multipliers to generate a high voltage that is many times greater than the input voltage. Condensers are widely used in various kinds of voltage converters, uninterruptible power supplies for computer equipment, etc.

Explaining what a capacitor is, one can not help saying that this element can serve as an excellent storage of electrons. However, this function actually has certain limitations because of the imperfection of the insulating characteristics of the dielectric used. Nevertheless, the capacitor has the property of storing electric energy for a long time when it is disconnected from the charge circuit, so it can be used as a temporary power source.

Due to their unique physical properties, these elements have found so wide application in the electronic and electrical industries that today it is rare which electrotechnical product does not include at least one such component for any purpose.

Summarizing, it can be stated that the capacitor is an invaluable part of a huge number of electronic and electrical devices, without which further progress in science and technology would be unthinkable.

That's what a capacitor is!