Which term refers to the rotating part of an electrical machine that carries current and interacts with the magnetic field to produce torque?

• A. Amplifier
• B. Autotransformer
• C. Bridge circuit
• D. Armature

Answer: (D)

The rotating current-carrying component that sits in the magnetic field to produce torque is the armature. In a motor, the armature windings (or conductors on the rotor) carry current and interact with the magnetic flux from the stator or field windings. This interaction creates magnetic forces on the conductors; the sum of these forces generates torque, causing rotation. The other options describe devices or networks (an amplifier, a transformer winding, or a bridge circuit) that don’t represent the rotating, current-carrying part of an electrical machine, so they don’t fit as the term for what produces torque.