How to Wire a 12 Volt DC to 120 Volts

In order to wire a 12 volt DC appliance into a 120 volt AC circuit, it s necessary to use a power converter. A power converter or adapter converts the incoming AC voltage into a lower DC voltage. AC adapters are widely used to allow for 12 volt DC equipment, such as car audio devices and scanners, to be plugged into a 120 volt residential power supply. Without the converter, the high voltage of the residential circuit would severely damage the 12 volt equipment.

Some power converters can be plugged directly into a 120 volt receptacle.
  1. Inspect the power converter. Some converters have an outlet plug on one end and can be plugged directly into a residential receptacle. Converters that do not have outlet plugs should have the 120 volt terminals clearly labeled.

  2. Connect the black, or hot, wire of the power source to one of the 120 volt terminals. Connect the white, or common, wire to the remaining 120 volt terminal.

  3. Look at the other side of the converter. Determine which of the 12 volt terminals is negative. This should be marked on the converter.

  4. Connect the negative wire of the device that the converter will power, usually a black wire, to the negative output terminal of the converter. Connect the positive wire, usually red, to the positive output terminal of the power converter.


  • Do not attempt to wire a converter into a circuit with the power supply connected. This could result in serious injury and damage to equipment.
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