Capacitors

A capacitor is one of the basic passive electronic components. Its task is to store energy in the electric field. The amount of stored energy is described by the capacitance of the capacitor, which is expressed in farads (F). The capacitance measured in full farads is not very common. Typically, capacitors have the capacitance of micro- (µ), nano- (n), pico- (p) farads.
The second basic parameter of a capacitor, apart from its capacitance, is its maximum operating voltage. Due to its design, a capacitor is susceptible to the so-called breakdown. Therefore, each capacitor has a parameter that defines the maximum voltage that can appear between its terminals. After exceeding it, a breakdown may occur, resulting in a short-circuit of the capacitor.

Capacitor – design and principle of operation

Capacitors are made of two conductors (capacitor plates) separated from each other by a non-conductive dielectric material. It can be any insulating material such as: air, plastic, ceramics, paper. The operation of a capacitor is based on Coulomb's law. According to that law, the media on both plates of the capacitor interact with each other. Media with the same charge repel each other, while those with the opposite charge attract each other. The effect of such a phenomenon is the presence of opposite charges on the capacitor plates. Their number is equal on both sides. Thanks to the dielectric material contained between the plates, the flow of charges is impossible, and this results in the formation of an electric field.

Types of capacitors

There are many different types of capacitors available on the market, including customized designs for specific tasks. Some of the types of capacitors available at TME are described below. Ceramic capacitors and MLCCs – these are some of the most common electronic components. What is interesting, the number of such capacitors manufactured in a single year is about one trillion. Ceramic capacitors owe their name to the ceramics used as an insulating material. MLCCs (multi-layer ceramic capacitors) are a subtype of conventional ceramic capacitors. An MLCC is a ceramic capacitor made in a multi-layer process. Ceramic capacitors do not have a specific polarisation, so they can be used in AC circuits, they are also available in both THT (through-hole mounting) and SMD (surface mounting) versions.

Electrolytic capacitors – the second most common type of capacitors are electrolytic designs. Thanks to the use of electrolyte, they offer much larger capacitance than ceramic capacitors. Almost all of them require appropriate polarisation – incorrect incorporation of such a capacitor into a circuit may even result in its explosion. These capacitors are also available in THT and SMD versions.

Trimmer – it is a variable capacitor, also called a tuning capacitor or tuning condenser. As the name suggests, the capacitance of such a capacitor can be freely adjusted. Trimmers were used in older designs of radios. At TME, several modern SMD trimmers are available.

Supercapacitors – they are a type of electrolytic capacitors and are able to store huge amounts of energy. Thanks to a special design, their capacitance reaches up to 3kF. In practice, it can be said that supercapacitors combine features of conventional capacitors and rechargeable batteries. Charging speed is their great advantage.