Reply to "How to determine DC positive wire and negative wire from a wall plug transformer?"

SteveHOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

With a digital meter set to DC Volts, touch its leads to the DC wall wart output wires and observe the reading on the meter display. If the reading is positive, then the red positive meter lead is connected to the power supply positive wire. If the meter shows a minus in front of the voltage reading, then the positive meter lead is connected to the power supply negative wire.

Note that an analog meter is different and the meter needle will try to move backwards if polaity is reversed.

8/14/229:18 AM

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