What is a capacitor?

A capacitor is a two-terminal electrical component. Together with the inductor and resistor, the capacitor is one of the most crucial passive components in a circuit. It is not easy to find any type of circuit without this component.

Capacitors are remarkable for their ability to store energy as a fully charged electric battery. Caps are what engineers refer to them and they possess all sorts of critical applications in circuits. Typical applications include local voltage spike suppression, energy storage, and complex signal filtering. Capacitance is the known effect of a capacitor.

How is a capacitor made?

The schematic symbol for a capacitor in engineering is a close resemblance to how it's made. A capacitor is made with two metal plates and an insulating material called the dielectric. The metal plates are placed in parallel, which is also close to each other. The dielectric sits between them to ensure their total separation. 

The insulating materials for making dielectric include ceramic, plastic, paper, glass, rubber, or any materials that can impede the current flow.

The plates are made of conductive materials such as Tantalum, silver, aluminum, or other metals. Each of them is connected to a terminal wire, which is what eventually connects to the rest of the circuit.

What are different types of capacitors?

  • Ceramic capacitors

  • Aluminum and Tantalum electrolytic

  • Supercapacitors

  • Other types: film capacitors, variable capacitors

How does a capacitor work?

How the capacitor is constructed decides how many farads it has and indicates the capacitance of the capacitor.

A larger capacitance requires a larger capacitor. Plates with more overlapping surface areas provide more capacitance, while more distance between the plates indicates less capacitance. The material of the dielectric even affects how many farads a cap has. The equation to calculate the total capacitance of a capacitor is the following: C=εr*A/(4*pi*d).

Where εr is the dielectric's relative permittivity (a constant value determined by the dielectric material), A is the area where the plates overlap, and d is the distance between the plates.

What are the applications of a capacitor?

Many capacitors in circuits, especially in integrated circuits, are decoupling. These capacitors are to suppress high-frequency noise in power supply signals. Capacitors take small voltage ripples as the higher ones would harm the ICs out of voltage supply. These components have another name as bypass caps, that act as a power source which bypasses the power supply.

Capacitors can also filter the power supply, filter signal, store and supply energy. Compared to a battery, they have much lower energy and capacity. However, the charge and discharge rate as well as their life span are more significant.

Capacitors can be applied to various sectors including military, medical, commercial applications, and many more across aluminum, film, tantalum, ceramic, and paper dielectrics. Capacitors are indispensable in most circuits, hence, play an essential role in the electronic and embedded world.

Who manufactures capacitors?

There are many capacitor makers around the world but the Japanese brands have received the most recognition from capacitor users. Some of the international well-credited manufacturers of capacitors are TDK, Rubycon, Samsung, Taiyo Yuden, Panasonic and Vishay. Apart from these giants, there are also Arcotronic (Kemet), Stelco (Sumida), ASC, Cal Chip, CDE, Faratronic, and Genteq (GE), who also produces high-quality capacitors.

Where to buy capacitors?

Apart from the manufacturers of capacitors, purchasers can rely on the electronics distributor networks. At BD Electronics Ltd. we offer a high-quality service and delivery of industry-leading, high-performance capacitance solutions to our customers worldwide. A comprehensive line of surface-mount and through-hole capacitor technologies is available to order from BD Electronics LTd. BD Electronics Ltd. has developed a strong network of suppliers and partnerships with various manufacturers within the industry. This allows us to meet all of the customer demands of capacitors with a short lead time. At BD Electronics Ltd. we can provide our customers with professional service and the most reasonable quotes in the market together with a rapid delivery of the goods while maintaining the highest standards of the components' form, fit, and functionality.

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