About the polarity of aluminum electrolytic capacitors
Aluminum electrolytic capacitors have polarity due to an internal structure that comprises an anode foil with withstand voltage and a cathode foil with essentially no withstand voltage.
Refer to the FAQ article for details about the internal structure and reverse voltage application.
If the polarity is accidentally reversed, a chemical conversion reaction occurs on the cathode foil surface, which has low withstand voltage. This can lead to problems such as gas generation, heat generation, pressure valve operation, or rubber seal separation.
Aluminum electrolytic capacitors have printed characters to indicate the cathode, so please pay sufficient attention during mounting.
- Cathode indicator for surface-mount products
(side printed with black text on the case indicates the cathode)
- Cathode indicator for radial-lead type products
The side with the white band on the sleeve or with the shorter lead line (excluding parts with processed terminals) is the cathode.
For products often mounted via manual insertion, we offer a line of products featuring terminals designed to prevent incorrect insertion.
LIN terminal
(change the board hole direction based on the +/-)
IJ terminal design
(use an elliptical shape for the board hole on the cathode side)
About the processed terminals for radial lead type capacitors.
If you have any questions or inquiries that do not apply to the above, please contact us at the following address.