Aluminum Electrolytic Capacitors

An aluminum electrolytic capacitor, also known as an electrolytic cell, is a type of capacitor that utilizes an electrolyte, often aqueous electrolyte, as the dielectric material. It is formed by the combination of two layers of metals that hold an electrolyte between them. The two layers are usually an aluminum oxide film coated with an electrolyte, and a metalized inner layer, with an additional cathode at the bottom of the device.

The aluminum electrolytic capacitor has become a popular choice among many electronics applications due to its excellent electrical characteristics; with its cost benefit and compliance with many international safety standards, it is quickly becoming the choice for many of today’s applications. Aluminum electrolytic capacitors are available in a wide range of packages, ranging from tiny surface mount components to large cylindrical sizes.

Application Fields of Aluminum Electrolytic Capacitors

There are many applications that use aluminum electrolytic capacitors due to their excellent electrical parameters as well as their cost benefit. Some of the most common application fields for aluminum electrolytic capacitors include:

• Circuitry applications which require a large capacitance range
• Analog and radio frequency (RF) circuits
• Decoupling and bypassing circuitry
• High frequency telecommunication systems
• Automotive electronics
• High power electronic ballasts
• Power supplies (AC/DC, switch mode)
• Portable electronic devices

Aluminum electrolytic capacitors can be used in a variety of other applications as well, such as signal processing, filtering, storage, modulation, and even military applications.

Working Principle of Aluminum Electrolytic Capacitors

The basic working principle of an aluminum electrolytic capacitor relies on two layers of metal that sandwich a thin sheet of dielectric material. The two layers are typically a thin aluminum oxide film, and a metal layer. The metal layer is either connected or "sprayed" with an electrolyte, which in turn acts as the dielectric material in the capacitor.

When an electric current is applied to the capacitor, the metal layers are forced together, creating a stable electric field between them. The electric field is used to store electrical energy, and the capacitor is able to hold this energy and release it when there is an increase in current. The capacitance of the device is then determined by the thickness of the dielectric layer between the metal layers and its distance away from each other.

The aluminum electrolytic capacitor is then able to store electrical energy for long periods of time, and can be used to control electrical flow in circuits. It is also very efficient at providing power when it is needed, and is used in a variety of applications such as stabilizing power in AC and DC motors, decoupling and bypassing circuitry, high frequency telecommunication systems, and much more.