Devices in the x-ray circuit that operate on the principle of mutual induction are called

• A. Rectifiers
• B. Generators
• C. Timers
• D. Transformers

Answer: (D)

Mutual induction occurs when a changing current in one winding induces voltage in a second winding that is magnetically linked to it. In x-ray equipment, the device that uses this principle is the transformer, which has primary and secondary windings on a common core. When alternating current flows in the primary, it creates a changing magnetic flux that links both windings, inducing voltage in the secondary. The voltage ratio follows the turns ratio (Vp/Vs = Np/Ns), enabling the circuit to step the line voltage up to kilovoltage for the x-ray tube (or down for other parts of the circuit) while keeping power roughly conserved.

Rectifiers use diodes to convert AC to DC; timers control exposure duration; generators produce electricity via induction in a rotating coil, not through two closely coupled windings transferring energy. So the device that operates on mutual induction in the x-ray circuit is the transformer.