What is the role of the primary circuit in a transformer?

The primary circuit in a transformer is crucial because it is the component where the input voltage is applied. When an alternating current flows through the primary winding, it generates a magnetic field. This magnetic field creates a magnetic flux in the transformer core, which is essential for the operation of the transformer. As this magnetic flux links with the secondary winding (the other set of coils), it induces an alternating voltage in the secondary circuit according to Faraday's Law of Electromagnetic Induction.

Understanding this role is fundamental to grasping how transformers work, as the transformation of voltage levels between the primary and secondary circuits relies on the primary circuit’s function of inducing this magnetic flux. This concept is integral to the operation of transformers, used widely in electrical systems for voltage regulation and distribution.