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I purchased a power adapter so that I could put a different plug on it, but when I cut the wire and stripped it, it didn't have a colored jacket on it. The brick does not have a diagram on it, so I have no way of knowing which is positive, and which is negative.

I have a multimeter, and set it to AC Voltage, and touched the red lead to one wire, and the black to the other. it was a positive voltage reading. I switched the leads and wires, and I got a postive voltage again. This is the power adapter I used:

Power Adapter

This is the multimeter I'm using:

Multi-Meter

Thank you

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This adapter is just a fused transformer in a box. It gives an isolated ac voltage output. There is no polarity in such a system. One wire will have a sinusoidally varying voltage around the other, sometimes positive, sometimes negative. Therefore you may connect the wires either way.

If you want a dc output, with one wire having a constantly positive voltage above the other, you bought the wrong item.

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