The basis for transformer operation is the use of alternating current due to what phenomenon?

The basis for transformer operation is the use of alternating current due to what phenomenon?

• A. Mutual inductance
• B. Capacitance
• C. Inductance
• D. Resistance

Answer: (A)

Transformers work through electromagnetic induction between two windings that share a magnetic path. The key phenomenon is mutual inductance: a changing current in the primary coil creates a changing magnetic flux that links both windings, so the secondary coil experiences a induced voltage proportional to the turns ratio. Alternating current is essential because it keeps the magnetic flux continuously changing; with direct current, the flux builds up and then becomes steady, so after the initial transient there’s no changing flux to induce a sustained voltage in the secondary. Capacitance involves electric fields and energy storage in a capacitor, not the transfer between coils. Inductance describes a coil’s opposition to changes in its own current, but by itself doesn’t couple energy to the other winding. Resistance just causes heating and losses. So the best explanation is mutual inductance as the enabling mechanism for transformer action.

Transformers work through electromagnetic induction between two windings that share a magnetic path. The key phenomenon is mutual inductance: a changing current in the primary coil creates a changing magnetic flux that links both windings, so the secondary coil experiences a induced voltage proportional to the turns ratio. Alternating current is essential because it keeps the magnetic flux continuously changing; with direct current, the flux builds up and then becomes steady, so after the initial transient there’s no changing flux to induce a sustained voltage in the secondary. Capacitance involves electric fields and energy storage in a capacitor, not the transfer between coils. Inductance describes a coil’s opposition to changes in its own current, but by itself doesn’t couple energy to the other winding. Resistance just causes heating and losses. So the best explanation is mutual inductance as the enabling mechanism for transformer action.