Power transformers convert power-level voltages from one level or phase configuration to another.

Signal transformers transfer information from one circuit to another by electromagnetic induction.

Toroidal transformers typically consist of copper wire wrapped around a cylindrical core.

Audio transformers are involved in the transmission of voice or sound signals.

RF transformers transfer energy from one circuit to another by electromagnetic induction.

Current transformers are used to step down current in a very predictable fashion with respect to current and phase.

Voltage and potential transformers are used to measure voltage in electric circuits.