Identifying polarity

[rrs]

Hi guys I have a tricky one.

I have an Axel Electrolytic that has me a little weary on the polarity. Whilst it has the negative markings down the side with what looks ile arrows pointing to one end It also has has the Long lead on that end (normally positive) and short on the other.

I cannot identify any other features and the datasheet only says "Negative terminal identified" under MARKINGS.

Im 90% sure the negative is the way of the arrows but would like to be much more surer than that.

http://www.mouser.com/ds/2/427/138aml-239889.pdf
It's the blue one above in the picture

 

[Gareth Connor]

With reference to the linked photo, the neg leg is on the LEFT, it connects to the can, the arrow points towards neg.

 

[CJ]

hook your DMM to the cap while set in ohms

red clip lead = pos

black = neg

clip leads will match polarity of cap of ohms slowly go up to megohms

if resistance drops instead, then cap is hooked up backwards with multimeter

flip leads and try again

if you need the physics and chemistry behind this, wait for a propeller head to post up,  ;D

 

[audiomixer]

Nice one CJ, will have to try this.....

- Michael

 

[mjrippe]

I have come across at least one cap where the "wrapper" was put on backwards with the "-" aimed at the positive lead.  Fortunately I saw it before installing it.