Transformers operate based on which principle?

Transformers operate fundamentally based on the principle of electromagnetic induction. This principle states that a changing magnetic field can induce an electromotive force (EMF) in a conductor. In the context of transformers, when alternating current flows through the primary winding, it creates a magnetic field that varies with time. This changing magnetic field then induces a voltage in the secondary winding through the magnetic flux linking both windings.

While mutual inductance refers to the interaction between the two windings that allows for this transfer of energy, it is underpinned by the broader principle of electromagnetic induction. Thus, the correct understanding focuses on electromagnetic induction as the essential operating principle of transformers as it encompasses the dynamics of how voltage is induced between the two coils.

In contrast, resistance heating relates to the loss of energy as heat due to resistance in electrical components, and capacitive reactance involves the opposition to the change of voltage in a capacitor. Neither of these principles directly describes how transformers function in transferring electrical energy.