Two layers Supercapacitor farad capacitor polarity?

[Folxs]

Hi, I got supercap but I can't find where he have "+" and "-"? There are only triangle arrows on the side - what does it mean? Maybe it mean, that "-" is on the top?
I read somewhere that supercaps may have no polarity, is it true?

[keeney123]

Re: Two layers Supercapacitor farad capacitor polarity?

Usually the arrow points to the negative terminal. However if it is a old cap it could go either way. The below is a test that can be done although the author does not guarantee 100 % success in the measurement.

Try this.
I have used the following method for many years with complete success. This does not mean that it is sure to work for you but that it has a good chance of doing so. When an aluminum electrolytic capacitor is operated with correct polarity the case operates at a slightly positive voltage relative to the negative terminal.
If the capacitor is operated with reverse polarity the case voltage is substantially more positive than when polarity is correct.
A PCB with many capacitors on can be checked by measuring Vcase relative to ground for capacitors with their negative lead grounded. (Otherwise measure Vacse to v- for that cap).
Reverse polarity capacitors will have substantially higher Vcase-Vnegative. This works extremely well in practice. (I have never seen this effect commented on anywhere else).
Testing:
Use a voltage less than half of the capacitor's working voltage.
(1) Apply voltage to capacitor pins and measure voltage from -ve pin to case.
(2) Reverse voltage and repeat.
The arrangement which has the LOWER voltage on the case relative to the negative pin is the correct one.
eg say you used a 2V supply.
In orientation 1 the case was at say +0.5V relative to negative.
In orientation 2 the case was at say 0.15V relative to negative.
Orientation 2 is correct.
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answered Aug 24 '12 at 20:53

Russell McMahon

[Folxs]

Re: Two layers Supercapacitor farad capacitor polarity?

Thanks for Your reply! It is very valuable knowledge for me, and I definitely will use it in the future. But in this case, we can see - that one side of cap is one polarity pin. So there is no case of cap, like in a cap, that have two legs on one side.
I think, that this arrows show that "-" is on the top of cap. I will give him 5.5V in this situation and observe
P.S. It havent 1.5F, I knew that is fake - good quality LCR meter shows only 2mF