I think I've seen every type of polar component mis-marked of the years
- keeps you on your toes.  Seems to me I remember something  about the
smoke from fried tantalums being toxic so it might be prudent to add
ventilation to the safety precautions.

>-----Original Message-----
>From:  Raymond Klein [SMTP:[log in to unmask]]
>Sent:  Thursday, June 03, 1999 12:45 PM
>To:    [log in to unmask]
>Subject:       Re: [TN] Tantalum caps and the big bang
>
>Ron,
>
>In the past 20 or so years I've seen about 6 lots of tant caps the were
>polarity mis-labeled. They get quite hot and pop. One even smoked a trace
>on the PWB. (My fault for making it too thin).
>
>You can test caps by putting them directly across a DC supply at 1/2 the
>rated voltage. The supply should be able to supply at least 1 amp. If the
>cap gets hot in a few seconds its "+" lead (what ever its marking) is
>connected to the "-" lead of the power supply. Wear safety goggles as com
>caps can fail spectacularly. Also be careful touching them as they can
>raise a blister.
>
>Good luck - Ray Klein
>
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