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How to Alter AC Voltage to a Lower Value Other Than a Transformer

A circuit that uses alternating-current (AC) electrical energy may not be able to directly use the voltage from a wall outlet. For many applications, voltage reduction is handled by a step-down transformer. However, if a suitable transformer is not available or is not desirable for use in the circuit, you may also choose to reduce the voltage of the AC signal by using resistors.

Both AC and DC power follow the principles explained by Kirchhoff's Circuit Laws. An electric circuit can be wired using resistors to create a voltage tap at the desired voltage level. This type of circuit is called a voltage-divider circuit.

Things You'll Need

Electrical wire
Electrical pliers
Electronic solder
Soldering iron
2 solder-type ring terminals
2 100-kiloohm resistors
12-volt AC power supply
Digital multimeter

Instructions

- 1
  Cut four lengths of electrical wire, with each wire segment being 6 inches long. Strip 1/2 inch of insulation from the ends of each wire.
- 2
  Place one of the ring terminals over one end of the first wire. Melt a small drop of solder to both the terminal and the wire end. Use the tip of the soldering iron to smooth out the soldered joint until it is shiny and free of lumps. Use this procedure to solder the remaining ring terminal to one end of the second wire.
- 3
  Twist together one end of the third wire with one of the leads from the first resistor and solder this joint.
- 4
  Twist the free lead from the first resistor together jointly to one of the leads on the second resistor, and with the loose end of the first wire. Solder this electrical joint.
- 5
  Twist one end of the fourth wire together jointly with the loose end of the second wire, and with the unoccupied lead from the second resistor. Solder this electrical joint.
- 6
  Connect the loose end of the third wire to one of the electrical terminals on the power supply. Connect the loose end of the fourth wire to the remaining electrical terminal on the power supply. Turn on the power supply.
- 7
  Turn on the multimeter and set the measurement scale to "Volts AC." Attach the red multimeter probe to the ring terminal at the end of the first wire. Attach the black multimeter probe to the ring terminal at the end of the second wire. Check the multimeter display; the voltage between the two ring terminals will be 6 volts AC.

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