Wires from a small plug-in transformer


Old 07-14-14, 05:25 PM
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Wires from a small plug-in transformer

There are two wires coming out of the transformer. One has a stripe and one does not. It is a DC output of 12V. Which one is positive and which one is negative. I have used these transformers to trickle charge small rechargeable batteries before.Just for get which is + or -.
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Old 07-14-14, 05:42 PM
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There is no set rule. It could be either polarity. Sometimes it's shown on the wall wart.
If not.... you'll need a voltmeter to check.
Old 07-14-14, 08:06 PM
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You can use a potato if you don't have a meter. How to Use Potato to Test the Polarity of a Battery

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