Transformers convert alternating current (AC) from one voltage to another without changing the frequency. When American William Stanley, Jr. (1858-1916) invented this master of conversion (based on an idea of Lucien Gaulard and John Dixon Gibbs) in 1885, he paved the way for televisions, computers, battery chargers, and lamps. As a result, Stanley was invited to go and work for the entrepreneur George Westinghouse.
Transformers take advantage of Michael Faraday's principle of mutual inductance, which enables one coil to induce a current in another coil. The ratio between the input and output currents is determined by the number of loops in the two respective coils. Thus a current can be raised from low voltage to high voltage with relative ease, the significance of which is driven by the fact that a low voltage transmitted over a large distance will dissipate much of its energy, whereas high voltages retain most of their energy.
As wonderful as it would be to have hundreds or even thousands of volts of current streaming through our walls, it would be very dangerous, and for this reason it was recommended that Stanley's invention be used to return the current to appropriate voltages. Had the current been transmitted at these lower voltages, it would have been leaking energy like a hosepipe made out of teabags.
Stanley's transformers were first put to use in March 1886 when they powered businesses along the main street in Great Barrington, Massachusetts. They were a huge success, and the basic design is still in use well over a hundred years since they first appeared, even though the appliances they power have themselves been transformed again and again.
