How Electrical Transformers Work

What is an Electrical Transformer?

A transformer is a device for changing the voltage of electricity. In popular use, it refers to the type of transformer that steps high voltage electricity down to the level necessary for domestic use. If you have electrical feed wires on telephone poles in your neighborhood, look around. Transformers in America often appear as large cylinders perched atop a telephone pole, with three or four feed cables running into nearby houses.

Mutual Induction

A transformer changes voltage by means of mutual electromagnetic induction. The electrical current running through the primary coil/circuit is used to create a magnetic field. Changes in the current will result in changes in the magnetic field, which in turn will alter the voltage of the secondary coil/circuit. The transformers used in residential areas are always used to take the high voltage electricity used to transmit power from generating plants, and take them down to the lower voltage used in homes and businesses.

Energy Efficiency

One of the amazing things about transformers is that they are perhaps the most energy efficient machines ever designed by man. Most designs suffer very little power loss in changing voltages. The least efficient designs are actually those found in the common power adapters, such as the one attached to laptop computers. However, even these transformers are more than twice as energy efficient as an internal combustion engine, for example.