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How can I tell which wires on my 12V DC adapter are positive and negative if I've cut off the plug end?
I have a 12V DC adapter, and I needed to use it in an electronics project. I cut the round plug end off of it so I could use a breadboard for my project before I go and get a PCB fabricated. How can I determine which wire is positive and which is negative. I don't wanna blow up any Capacitors!
6 Answers
- Sa TLv 51 decade ago
For you to ask it means that you do not have a meter of any kind. Look at the colour of the wires. They are ususally either red & black or white&black. Black is then the negative. If you cannot tell by the colour, then, use method suggested by Irv S. If you have a diode you can test with a lamp in series. If you have a diode and no lamp, use your own tongue in series. One way will just tickle your tongue, the other will chock it -harmlessly. [Assuming you know which way round you forward-bias a diode]
- Anonymous1 decade ago
Do you have a multimeter? If so, plug in the adapter and measure the voltage across the 12 volt output. If you guess the positive and negative right the output will read +12V and if wrong, it will read -12V.
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- 4 years ago
I m using a 12 v dc adapter ,so I need to know which one is positive and negative
I don't hav Multimeter ....
So plz answer me
