Each type of electrical transformer fills a specific role.

Electrical transformers change the voltage of an electrical current that passes through them. They use a magnetic core wound with wire to alter the voltage, usually either increasing it or decreasing it as needed. There are multiple types of electric transformers, each filling a different role in the circuits they are installed in.

Step-Up Transformer

Step-up transformers provide a higher output voltage than input voltage, creating an overall voltage increase when a current passes through them. The amperage of the current is reduced in the process.

Step-Down Transformer

Step-down transformers are the opposite of step-up transformers, providing a lower output voltage than their input voltage. An overall voltage decrease occurs when current passes through, though current amperage is increased.

Isolation Transformer

Isolation transformers transfer a current from a primary circuit to a secondary one without adjusting voltage. The current becomes isolated in the secondary circuit, preventing interference and potentially damaging voltage buildup.

Buck Boost Transformer

Buck boost transformers cause small increases in voltage, similar to a step-up transformer but with a much smaller change.

Three-Phase Transformer

Three-phase transformers use three cores linked in a specific sequence to adjust currents passing through electrical lines. The use of three cores allows larger amounts of current to be adjusted at a faster pace. These transformers are available in step-up, step-down and other varieties.

Single-Phase Transformer

Single-phase transformers regulate current that is supplied by a variable power supply, providing a constant current to simple devices such as light bulbs and heaters.

Voltage Transformer

Voltage transformers are designed to provide adjustments to specific voltage levels. They are available in low-voltage, medium-voltage and high-voltage varieties.

Autotransformers

Autotransformers feature only a single winding of wire around their core with three or more electrical connection points along the wire. These connection points allow different electrical systems to be connected by a single transformer, even if the systems are operating at different voltages.

Other Types

Other transformer types include oil-filled transformers that use oil as an insulator and coolant; dry transformers, which are air-cooled; and industrial control transformers that adjust voltage to meet the needs of motor controls and other industrial control circuits. Custom transformers and transformers designed for use in specific equipment also exist.