By 'coupled circuits' we mean two or more circuits, often in the form of multi-turn coils sharing a magnetic circuit, where the magnetic flux produced by the current in one coil not only links with its own winding, but also with those of the other coils.

What is meant by coupled of coils?

An electric circuit is said to be a coupled circuit, when there exists a mutual inductance between the coils (or inductors) present in that circuit. Coil is nothing but the series combination of resistor and inductor. In the absence of resistor, coil becomes inductor.

What does a coupled inductor do?

Coupled Inductor: - A coupled inductor is an inductor with two or more windings on the same core which takes advantage of magnetic coupling to influence the behavior of each winding on the other.