Which device provides energy transfer between isolated circuits using magnetic coupling?

Which device provides energy transfer between isolated circuits using magnetic coupling?

• A. Transformer
• B. Capacitor
• C. Resistor
• D. Inductor

Answer: (A)

The concept here is transferring energy between isolated circuits using magnetic coupling. A transformer does this by having two windings wrapped on a shared magnetic core. When alternating current flows in the primary, it creates a changing magnetic flux that links to the secondary winding. This changing flux induces a voltage in the secondary proportional to the turns ratio, allowing power to move from one circuit to another while keeping the circuits electrically isolated. This magnetic coupling is key: it enables energy transfer without a direct electrical connection. A capacitor couples energy through electric fields and isn’t primarily about magnetic transfer. A resistor wastes energy as heat and doesn’t transfer energy between distinct circuits. An inductor alone stores energy and can couple to another coil, but true energy transfer between isolated circuits with magnetic coupling relies on the transformer’s two winding arrangement on a core.

The concept here is transferring energy between isolated circuits using magnetic coupling. A transformer does this by having two windings wrapped on a shared magnetic core. When alternating current flows in the primary, it creates a changing magnetic flux that links to the secondary winding. This changing flux induces a voltage in the secondary proportional to the turns ratio, allowing power to move from one circuit to another while keeping the circuits electrically isolated.

This magnetic coupling is key: it enables energy transfer without a direct electrical connection. A capacitor couples energy through electric fields and isn’t primarily about magnetic transfer. A resistor wastes energy as heat and doesn’t transfer energy between distinct circuits. An inductor alone stores energy and can couple to another coil, but true energy transfer between isolated circuits with magnetic coupling relies on the transformer’s two winding arrangement on a core.