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How to Convert 240V to 120V

When you plug a device into a wall electrical outlet in a North American building, the voltage that the electrical outlet supplies is between 110 and 120 volts AC. For many other parts of the world, the voltage from a wall outlet is between 220 and 240 volts AC. Some electronic devices have a "dual-voltage" power supply that you can use with voltage inputs between 100 and 240 volts AC. However, not all electrical devices will operate properly under these circumstances. One way to solve this problem is by using a transformer to convert the voltage.

Things You'll Need

240-volt AC power supply
240v/120v transformer
Electrical wire
Electrical pliers
Soldering iron
Electronic solder
Solder-type spade terminals
Screwdriver
120-volt power receptacle

Instructions

- 1
  Cut four pieces of wire using the electrical pliers, with each piece being six inches long. Strip 1/2 inch of insulation from each wire end using the stripping edge of the pliers.
- 2
  Place one end of the first wire segment over one of the terminals on the transformer's primary side. Melt a small drop of solder to both the terminal and the wire, and smooth out the soldered joint until it is shiny and free of lumps. Solder one end of the second wire to the remaining transformer primary terminal.
- 3
  Solder one end of the third wire to one of the transformer secondary terminals. Solder one end of the fourth wire to the remaining transformer secondary terminal.
- 4
  Place the first spade terminal over the loose end of the third wire and solder the terminal to the wire. Place the second spade terminal over the loose end of the fourth wire and solder the wire to the terminal.
- 5
  Loosen one of the screws on the power receptacle's left-side terminal. Place the spade terminal connected to the third wire into the space between the screw head and the metal receptacle terminal. Tighten the screw so it holds the spade terminal snugly to the receptacle terminal, using the screwdriver.
- 6
  Loosen one of the screws on the power receptacle's right-side terminal. Place the spade terminal connected to the fourth wire into the space between the screw head and the metal receptacle terminal. Tighten the screw so it holds the spade terminal snugly to the receptacle terminal.
- 7
  Attach the loose end of the first wire to one of the AC power supply terminals. Attach the loose end of the second wire to the remaining AC power supply terminal. To use this circuit, turn on the AC power supply and plug a 120-volt device into the power receptacle.

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