I have found out that my dc barrel is tip positive. after cutting the the barrel I realized that there is on insulation inside the black insulation itself to identify which one is positive and which one is negative.
the only thing I can find out it, one wire has – – – – – on it, and the other has 300v 80C 14guage F11 A, and so on. Could the – – – – mean its positive 12v DC?
Best Answer
"Zip cord" or cable that has two conductors connected together via the insulating jacket, is frequently used for things like DC power supplies (wall warts), speaker cable, etc. Sometimes it will have a stripe, a texture, or printed characters on one side. The "- - -" should not be taken to mean negative. It's merely a marking. Always check which wire is connected to tip or ring using a continuity meter, and of course a volt meter to determine polarity provided by the supply.