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Polarity of Tantalum Caps

Started by tenwatt, April 01, 2011, 10:52:34 AM

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tenwatt

So I have this Tantalum cap that I'm putting on my Egodriver board.  How do I tell which side is positive?  My common sense guess is the right side, in the picture below, because it has the positive sign in the small lettering above that lead.  But that's my uneducated guess.

Not too bright....

gtr2

Usually the positive lead is slightly longer as well, but that doesn't look like the case based on your picture. Unless you already trimmed the leads.

Josh
1776 EFFECTS STORE     
Contract PCB designer

tenwatt

Quote from: gtr2 on April 01, 2011, 11:16:10 AM
Usually the positive lead is slightly longer as well, but that doesn't look like the case based on your picture. Unless you already trimmed the leads.

Josh
Nope, I didn't trim them yet.  I actually knew that believe it or not. :)

So am I correct in my assumtion of the print on the cap.  It doesn't look like it is really labeling the lead as much as it's just describing the cap.
Not too bright....

gtr2

1776 EFFECTS STORE     
Contract PCB designer

oldhousescott

The bar or stripe indicates the positive lead on a tantalum cap. Exactly the opposite of an electrolytic.

tenwatt

The third page here gave me my answer.  It's not so clear looking at the cap but the drawing here really helped.

http://www.kemet.com/kemet/web/homepage/kechome.nsf/vapubfiles/F3100_TaDipRad.pdf/$file/F3100_TaDipRad.pdf
Not too bright....

bigmufffuzzwizz

Quote from: oldhousescott on April 01, 2011, 01:02:57 PM
The bar or stripe indicates the positive lead on a tantalum cap. Exactly the opposite of an electrolytic.

Took me awhile to spot this the first time. Some of them also have a nice miniature plus sign.
Owner and operator of Magic Pedals