The transformer is one of the most useful of all pieces of electrical equipment, and one of the most vital to the power industry. The most often seen type of transformer is known as a three phase pole mounted step down transformer, and this type of transformer is an electrical device used to transfer energy from one circuit to another through the process of magnetic coupling. In order for this energy transfer to take place, no relative motion of the transformer parts is necessary. In addition, transformers are often used to convert energy from high voltage to low voltage, to change the impedance or to provide for electric isolation between the circuits.

The transformer is an essential part of the power grid and the transmission of power, and the transformer is able to provide for an economical way of transmitting power over the long distances needed in today's world. In fact, it was the transformer that was largely responsible for power generating companies choosing alternating current for energy generation.

One of the earliest experiments in developing telephone used a device called an audio frequency transformer. This device, which at the time was called a repeating coil, played an instrumental role in the development of the telephone. In today's world the audio frequency transformer has largely been replaced by other technology, but it these transformers are still used in some electronics.

The device we know as a transformer can be virtually any size, from the thumbnail sized transformer inside a microphone to the huge units that are used by power generating companies to connect far flung parts of the power grid. No matter how big or how small, however, the transformer operates according to the same basic principles, using similar parts and similar technology.

Even though technology has changed quite a bit since the first transformers came onto the market, the transformer today remains an essential part of the power grid. When a transformer fails, many power customers are likely to be affected, and power companies work their hardest to keep their many transformers up and running 24 hours a day and seven days a week.

The power of the transformer has certainly improved our lives in a number of important ways, from heating our homes to lighting our way in the darkest night. Transformers and the power lines they connect to have allowed virtually every person in the country to enjoy a steady and reliable stream of electric power for their appliances and their lives.