The energy transfer between windings without direct electrical connection relies on what type of coupling?

• A. Inductive coupling
• B. Capacitive coupling
• C. Resistive coupling
• D. Electrostatic coupling

Answer: (A)

When windings transfer energy without a direct connection, it happens through inductive coupling. The primary current creates a changing magnetic field that links both windings on a common magnetic path (often a core). This varying magnetic flux threads the secondary winding and induces a voltage proportional to the turns ratio, which is the essence of transformer action. The core and tight coupling maximize this magnetic link, letting most of the energy flow through the magnetic field rather than through a conductor. Capacitive or electrostatic coupling would transfer energy via electric fields between conductors and is not the primary mechanism for power transfer in typical transformers, while resistive coupling would require a direct conductive path, defeating isolation. So the energy transfer relies on inductive coupling through mutual inductance.