Capacitors are used in a wide range of electronic devices and have been an essential component for a long time. In this blog, we take a look at what defines a capacitor and what the different types of capacitor are.
What is a capacitor?
A capacitor is a passive, two-terminal electronic component that is used to store electrical energy in an electric field. It consists of one or more pairs of conductors which are separated by an insulator, a non-conducting substance known as a dielectric.
What is capacitance?
The effect of a capacitor is known as capacitance, which refers to the ability of a system to store an electric charge.
What are the different types of capacitors?
We have outlined some of the most common and popular types below:
An electrolytic capacitor is a polarized capacitor which uses an electrolyte – a liquid or gel containing a high concentration of ions – to achieve a larger capacitance (ability to store electric charge) than other types. Most commonly, they are made from tantalum or aluminium. Since they are polarized capacitors, they can only be used in DC (direct current) circuits. They are typically used in power supplies and domestic appliances.
You may have heard of or used tantalum capacitors before, but these are actually a subcategory of electrolytic capacitors. They are made of tantalum metal and covered by a layer of oxide which acts as the dielectric. They are stable and reliable, with a long shelf life.
A film capacitor is a capacitor that uses a thin plastic film as the dielectric. Film capacitors are a non-polarized type of capacitor, meaning they are suitable for AC (alternating current) use. There are various types of film capacitor, including polyester, polystyrene, metallized, polypropylene and PTFE – all of these using different materials for the film. They are widely used in a variety of applications within the electronics industry because they are low cost and stable. Film capacitors are durable and long-lasting and are unlikely to fail.
A ceramic capacitor is a non-polarized capacitor which uses a ceramic material as the dielectric. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes. They are popular due to their small size and, since they are not polarized, they can be used in AC devices.
The most common type of ceramic capacitor used in the electronics industry today are the multilayer chip capacitor (MLCC) and the ceramic disc capacitor. The MLCC is the capacitor which has the highest volume of production, although there have been shortage issues recently. MLCCs are also frequently used in printed circuit boards (PCBs).
Mica capacitors refer to those that use mica, a group of natural materials, as the dielectric. The main type is silver mica capacitors which are made by combining two sheets of mica coated with the metal. They are very stable and their capacitance changes little over time. They are also popular because they can be used at high frequencies and mica doesn’t react with moisture or other substances.
We hope this brief guide to the different types of capacitor has been useful! If you are interested in capacitors, you can view our passive components range or simply browse using our product search function.