Question about capacitor



  • Hi, I'm not sure if troubleshooting forum is the right place as this is just a question. If not, please tell me.

    So I just found out an error with some of my temperature node.
    I did solder the capacitor backward on the radio.

    Node were working great and nothing exploded.
    I noticed it when I "copied" one I have to create another one.

    I soldered them in the right direction now, so I guess everything is right now.

    But my question is : should it have exploded ? From what I know and read about capacitor is that if they are wired backwards, the will blow up. I've been using this sensor from at least 2 months now.

    Is it because is such a low voltage ?

    Thank you



  • That's a good question. I assume that you have used an electrolytic capacitor, right? If it would have been a ceramic type: no worries, they don't have a polarity.
    The answers I could find in the internet for electrolytic capacitors varied quite a bit, but the consensus seems to be that they like to blow up in such cases, provided a high enough voltage. So I have two theories why yours didn't: either you have used a capacitor rated for a higher voltage and the 3.3V wasn't enough to destruct it. Or the current through the capacitor was limited because the 3.3V regulator could not provide more.

    Anyways I have read that you should replace such a capacitor that has been subjected to a reverse polarity to be sure because it could have taken long-term damage.



  • @mathea90 With such low voltage and current they are very unlikely to explode. Now if we had 12v at 3A it would be different story! Stick to ceramic if you can, they are used in mobile phones etc and offer low ESR as well. The best option IMO.



  • Thanks to both of you. I did solder it back. I will replace them just to be sure.


 

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