Electronic – Packaging polarity indication of a supercapacitor (polarity indicated by arrows)


I obtained some supercaps from an auction site.
As is often the case for low cost components from such sources, these do not have supplied data and such branding as there is does not appear traceable.

I would like to know if there is a standard for polarity for such devices and how likely it is that generic devices such as this one follow the "standard".
My samples have an arrow on the label which may indicate polarity, but this is uncertain.

To make my query specific, but also liable to be generally useful, here is a set of closely related questions:

  • What is the polarity of this supercapacitor (4F, 5.5V)?

  • How was the polarity determined in this case?

  • Is there a standard for polarity for such capacitors?

  • What does the arrow indicates?

image of two-cell stacked coin-like supercapacitor

Some details of specific product here

Including this diagram:

enter image description here

Best Answer

Since the product you purchased has no background information, you can't be certain. However, the convention for these stacked-disk type capacitors is polarity mark points to negative lead. This is the same as is the convention with conventional electrolytic capacitors.

For example, the Eaton KR-5R5V474-R:

Digkey image of the KR-5R5V474-R

Has its datasheet show:

device drawing of the KR-5R5V474-R showing polarity indication

Similarly, for the Panasonic EEC-S0HD224H:

Digikey image of the EEC-S0HD224H

Has the same arrow convention considering the asymmetric leads with polarity indicated in its datasheet:

device drawing of the EEC-S0HD224H showing polarity indication