Tantalum Capacitor and Aluminum Electrolytic Capacitor Selection and Application (II)

Application Considerations for Aluminum Electrolysis in Power Circuits

(1) Prevent halogen corrosion

Aluminum electrolytic capacitors are very sensitive to chlorine, bromine, etc. If halogen-containing fluxes, cleaning agents, fixatives, fumigants are used, halides may infiltrate into the capacitor through the sealing rubber plug, which can easily cause corrosion of the capacitor anodes. Accelerating capacitor fails after power-up. Therefore, the relevant sensitive halogen components used in the production process must be strictly controlled.

(2) Storage environment control and periodic activation

It is necessary to control the storage environment and time of the electrolytic capacitor and perform regular electrification. After aluminum electrolysis is stored in a high temperature environment for a long time, a chemical reaction occurs between the capacitor anodized film and the electrolyte, resulting in a decrease in with stand voltage and an increase in leakage current. When suddenly powered on, the capacitor voltage approaches the rated voltage, which may cause pressure failure or excessive leakage current to cause overheating failure. Corresponding to the single capacitor, especially the high-voltage capacitor, it needs to be activated after long-term storage. It is recommended to connect the 1KΩ protection resistor in series, gradually pressurize it to the rated voltage, and maintain it for about 1 hour, so that the capacitor anodized film can be repaired and the leakage current can return to normal level. .

(3) Reasonably layout the device on the PCB to keep the aluminum electrolytic capacitor away from the heat source

(4) According to product characteristics, select solid capacitors

For example: In the application of low voltage and high current output, use aluminum solid capacitors. Aluminum solid capacitors have extremely low ESR and high ripple current capability, making them ideal for low-voltage, high-current rectification and filtering applications.