A step-down transformer is used to decrease the voltage of an AC signal while increasing the electrical current. A step-down transformer uses transient electromagnetic fields applied across electrical windings to accomplish the voltage conversion. The proportion of the number of windings on each side of the transformer determines how much the voltage is decreased. For example, a 2:1 transformer will yield half as much voltage on the output side of the transformer when compared to the voltage on the input side of the transformer.

Cut a piece of wire 20 inches long. Strip off half an inch of insulating material from both ends of the wire.

Cut a piece of wire 14 inches long. Strip off half an inch of insulating material from both ends of the wire.

Wrap the 20-inch wire tightly around the bottom of the steel rod. Leave two four-inch electrical leads loose.

Wrap the 14-inch wire tightly around the top of the steel rod. Leave two four-inch electrical leads loose.

Connect one of the leads from the 20-inch wire to one of the terminals on the power supply. Connect the other lead from the 20-inch wire to the remaining terminal on the power supply.

Place one of the probes from the multimeter on one of the leads from the 14-inch wire. Place the remaining probe from the multimeter on the other lead from the 14-inch wire. Turn the multimeter on, and set the scale to “Volts AC.”

Turn on the power supply. The voltage across the 14-inch wire should be approximately 3 volts AC.