There are many different kinds of transformers, each made with different materials.

A typical power transformer begins with a core made from thin sheets of silicon transformer steel, coated with insulating varnish, and cut into “E”, or “I” or “C” shapes depending on the design of your proposed transformer. Typically there is a bobbin of insulating paper or plastic that insulates the inner windings from the iron of the core.

The transformer windings are placed on the bobbin. They maybe composed of copper, aluminum, or other conductive wire, and insulated with enamel or another similar insulating finish. Layers of insulating paper or plastic may be used to separate the primary from secondary windings, and to wrap the outer windings for protection. The transformer maybe finished with flying wire leads, or have terminal lugs of bolts installed for external connections.

Finally, bolts and mounting brackets may be applied to the core to facilitate mounting the finished transformer. Some transformers have their windings potted in epoxy for durability and noise reduction.