Aluminum and plastic cover sealed together to form an electrolytic capacitor. Compared with other types of capacitors, electrolytic capacitors in the structure exhibits the following distinctive features:
(1) an aluminum electrolytic capacitor working medium by means of anodic oxidation for generating a surface layer of thin aluminum foil of aluminum oxide (Al2O3), the oxide dielectric layer and the capacitor anode are combined into a complete system, both interdependent, not independent of each other; we usually refer capacitor electrode and dielectric are independent of each other.
Aluminum electrolytic capacitor winding core is made of aluminum foil anode, electrolytic paper, aluminum foil cathode electrolytic paper 4 layers from overlapping; core impregnation after the electrolyte, with
(2) aluminum electrolytic capacitors are formed on the surface of the anode foil Al2O3 dielectric layer, the cathode is not accustomed to think of our negative foil, but the capacitor electrolyte.
(3) the electrical leads from the negative foil in an electrolytic capacitor, an electrolytic capacitor as cathode and the electrolyte can not be directly connected to an external circuit, must form an electrical path through the metal electrode and the other portion of the other circuits.
An anode foil (4) aluminum electrolytic capacitor, the cathode foil are usually aluminum foil etching, the actual surface area much greater than the apparent surface area, which is an aluminum electrolytic capacitor generally has a large capacitance of the reasons. Since the aluminum foil having a plurality of fine pits, often need to use a liquid electrolyte can more effectively utilize the actual electrode area.
(5) Since the dielectric oxide film is an aluminum electrolytic capacitor is obtained by anodic oxidation of the way, and its thickness is proportional to the applied voltage of the anodic oxidation, so that, in principle, the dielectric layer thickness of the aluminum electrolytic capacitor can be artificially precise control.
Electrolytic capacitor uses
1. DC blocking: the role is to prevent direct and let pass through the exchange.
2. Bypass (decoupling): provides a low impedance path for the exchange of certain circuit elements in parallel.
3. Coupled: As connection between the two circuits, to allow communication signals and transmitted to the next-stage circuit
4. Filtering: This is very important for DIY, the capacitance on the video card basically this effect.
5. Temperature compensation: for the impact on other components is not enough to bring the temperature adaptability, and to compensate, improve the stability of the circuit.
6. Timing: capacitors and resistors used in conjunction to determine the time constant of the circuit.
7. Tuning: The frequency-dependent circuit tuning systems, such as mobile phones, radio, TV.
8. Rectifier: on or off-closed conductor switching element at a predetermined time.
9. Storage: store electrical energy, for the time must be released. Such as camera flash, heating equipment.