Group Ao Electronics analyzes the concept and application of aluminum electrolytic capacitors for yo
Article Source：QUNIO ELECTRONICS
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issuing time：2019-04-09
A capacitor is a "container" that can store electric charge. However, this "container" is a special substance, a charge, and its stored positive and negative charges are equally distributed on two conductor plates that are not directly conducting. So far, we can describe the basic structure of the capacitor: two conductor plates (usually metal plates) are separated by a dielectric.
The role of capacitors in electronic circuits is generally summarized as: AC, DC blocking. Capacitors are usually an integral part of the electronics by filtering, bypassing, coupling, decoupling, and turning electrical. In the days when LSIC and VLSIC have become popular, capacitors are still widely used in circuits of various functions as discrete passive components, and their important role in the circuit can be seen. As an important application field of capacitors, capacitors can be charged and discharged instantaneously compared with energy storage components such as batteries, and the charge and discharge current is basically unlimited, which can provide high power for equipment such as welding machines and flash lamps. Instantaneous pulse current. Capacitors are also often used to improve the quality factor of circuits, such as capacitors for energy-saving lamps.
The core of the aluminum electrolytic capacitor is formed by stacking four layers of an anode aluminum foil, an electrolytic paper, a cathode aluminum foil, an electrolytic paper, etc.; after the core is impregnated with an electrolyte, the aluminum shell and the rubber cover are sealed to form an electrolytic capacitor. Compared with other types of capacitors, aluminum electrolytic capacitors exhibit the following obvious features in structure:
1. The working medium of the aluminum electrolytic capacitor is to form a very thin layer of aluminum oxide (Al2O3) on the surface of the aluminum foil by anodizing. The oxide dielectric layer and the anode of the capacitor are combined into a complete system. Dependent, not independent of each other; we usually refer to capacitors whose electrodes and dielectrics are independent of each other.
2. The anode of the aluminum electrolytic capacitor is an aluminum foil on the surface of the Al2O3 dielectric layer. The cathode is not the negative foil that we are accustomed to, but the electrolyte of the capacitor.
3. The negative foil plays an electrical role in the electrolytic capacitor because the electrolyte as the cathode of the electrolytic capacitor cannot be directly connected to the external circuit, and the electrical path must be formed by the other metal electrode and other parts of the circuit.
