Tantalum cap with no polarity marking

[Chris_PL]

Hi everyone!

Any idea how to determine polarity on this thru-hole 4.7u/25V tantalum cap? There's absolutely nothing on it except manufacturer's logo, rating numbers i.e. 4.7 / 25 and legs are perfectly equal in length. I know that tantalum caps are often a "trap for young players" because they have markings on (+) instead of ( - ), but I already know this (it took a few blown caps though  )

[free_electron]

positive is side where the logo is printed. logo is asymmetrical from center.

but, this could be a better solution: Open window first then take a rubber band and put it around your index and middle finger. Hook the capacitor body over the rubber band so the body points away from you , the rubber band is between the legs and the legs point towards you.  Now spread index and middle finger in a v-shape, and using the other hand stretch the rubber band by pulling the capacitor legs towards you holding the hand with the rubber band on it at a steady distance from your body.
Aim through window and release the capacitor legs .... 

problem solved..

[ConKbot]

You can test by charging the cap In both polarities through a  high value resistor. ( couple hundred k ohms)  Which ever polarity has a higher voltage on the cap is the correct polarity.  The lower voltage means more leakage current in that orientation.

[c4757p]

Tantalum caps aren't just a trap for young players, they're smelly turds for anyone. Who cares which side is which, chuck it in the bin.


(I say, as I'm designing tantalums into something at this very minute. OK, they're not that bad...)

[Bored@Work]

Solder it into the circuit. Turn the circuit on. If you got the polarity wrong it'll blow up. If you got the polarity right it might blow up, too. In any case, problem solved.