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two chargers with different colored wires?

I have 2 chargers. My dog ate the original so I bought another, which my husband dropped in a cup of mountain dew. The plug in end was wet and won't work now. I want to put the wire from the new one to the plug in part of the old one. But the wires are different colors. One is red and black the other is red and green. Can I put the red and green together safely??

The usual way to determine the polarity of a DC voltage is by using a DC voltmeter, which is the same thing as a multimeter
http://en.wikipedia.org/wiki/Multimeter
on its DC voltage setting.

That is to say there is no way to say for certain which color wire the manufacturer decided to use for which polarity.  That's a choice that's left to the manufacturer.

That being said, there is sort of a loose convention, more like a tradition, of making black negative and red positive.  So that's probably the way the one with red and black wires was built.

So what about the one with one red wire and one green wire?  Well, I'll guess that for that one red is positive, and green is negative. But that's just a guess.

Like I said at the beginning,  a voltmeter would be very helpful for figuring out which wire is which, and that's the usual way things like this are done.
rboone2 (author) 2 years ago
Figured it out myself. The green wire is actually the ground wire so it goes with the black wire. and the black wire goes to the red wire.
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