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About the polarity of aluminum electrolytic capacitors

Aluminum electrolytic capacitors have polarity due to an internal structure that comprises an anode foil with a relatively high withstand voltage and a cathode foil with a relatively low withstand voltage.

Refer to the FAQ article for details about the internal structure and reverse voltage application.

Accidentally applying electrodes in the wrong direction has the potential to activate the pressure valve or cause rubber seal separation due to gas or heat generated by chemical reactions involving the cathode foil, which has a low withstand voltage.

Aluminum electrolytic capacitors have printed characters to indicate the cathode to ensure sufficient caution during mounting. We also recommend measures such as image inspections.

  • Cathode indicator for surface-mount products
the case indicates the cathode
(side printed with black text on the case indicates the cathode)
  • Cathode indicator for radial-lead type products
Cathode indicator
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.
Terminal code LI
LIN terminal
(change the board hole direction based on the +/-)

About terminal type snap-in type capacitors.

Terminal code IJ
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.

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