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So I went to a local electronics retailer, Communica in Cape Town yesterday. I had a small shopping list including:

  • 10x 10µF Ceramic Capacitor
  • 10x 0.1µF Ceramic Capacitor

The vendor didn't have any unpolarised capacitors, so he gave me the ones, as in the photo attached.

enter image description here

I immediately but respectfully commented, that this is a POLARISED electrolytic capacitor, and the sales chap cut me short, saying, it's unpolarised.

Am I subconsciously smoking something here? I admit I haven't been involved in electronics too long to have earned any badges, but I'm pretty sure that both the salesmen I asked are wrong.

I need the caps for decoupling in a USB + PIC32 MCU circuit (see image below), so I also think that 100V tolerance is a bit overkill, 10V will probably do, right?

enter image description here

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    \$\begingroup\$ Um, those big "NP" letters on the sleeve generally mean "Non-Polarized" ... Jamicon has a line of non-polarized electrolytic caps for audio applications. \$\endgroup\$
    – Adam Lawrence
    Commented Jun 5, 2013 at 19:48
  • \$\begingroup\$ Fair enough, but why are the legs of different lengths? I was under the impression NP = Negative Pole? \$\endgroup\$
    – josef.van.niekerk
    Commented Jun 5, 2013 at 19:49
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    \$\begingroup\$ Most likely they're using the same leads that they would use in a polarized capacitor, to cut down on costs. \$\endgroup\$
    – Adam Lawrence
    Commented Jun 5, 2013 at 20:35
  • \$\begingroup\$ NP = No Problem? \$\endgroup\$
    – Phil Frost
    Commented Jun 5, 2013 at 20:45

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Let's see: We have name Jamicon printed on the capacitor as well as NP. A simple search of Jamicon capacitors brought me to the website of Jamicon Electronics Corporation. Going to Capacitor->Product search menu brings us to the search interface.

I don't see any NP series capacitors, so I went to advanced search and used voltage and capacitance as inputs. It didn't produce any relevant results (the TK series, which it produces isn't what we have, from the datasheet description), so I went back to the basic search and checked capacitor descriptions.

I noticed term bi-polar in some of them and downloaded datasheets for the first one I saw. As it so happened, the datasheet was for NK series capacitor. The datasheet showed a picture of capacitor with NP mark and had Non Polarity in big letters on the first page and Standard non polarity series for using in polarity reversal circuits. in description.

So I guess that the capacitor isn't polarized. Also note that it doesn't seem to have the traditional polarized stripe on the body.

I hope that the thought process explained here will help you in future searches for part descriptions.

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  • \$\begingroup\$ The thought process definitely helps, thanks for taking the time to answer. \$\endgroup\$
    – josef.van.niekerk
    Commented Jun 5, 2013 at 20:00

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