How to determine polarity of electric wires.
July 27, 2011 12:38 AM Subscribe
I have two DC electric wires: one is positive, one is negative. Without buying anything, how can I tell which is which?
posted by brenton to Science & Nature (16 answers total) 6 users marked this as a favorite
Assume it's .5amp and 12 volt. This actually isn't just a theoretical situation though: I snipped the DC end of an AC adapter and now I can't remember which was which. The wires are identical. My plan is to use it as a car battery tender/charger, but I don't want to put it on backwards.
But also I'm interested in what cool science tricks there might be for detecting positive/negative. Go science tricks!