The transformer uses the principle of what?

The principle used by a transformer is mutual inductance. This principle involves the transfer of electrical energy between two windings or coils through a magnetic field. When alternating current flows through the primary coil, it generates a changing magnetic field around it. This magnetic field then induces a voltage in the nearby secondary coil due to the proximity and the nature of the magnetic lines of force.

The efficiency of transformers relies heavily on this principle, as it allows them to step up or step down voltage levels while maintaining power within the limits of energy conservation. The design of transformers is fundamentally based on mutual inductance, which enables them to effectively convert electrical energy from one voltage level to another with minimal losses.

Resistive heating refers to energy loss in the form of heat due to the resistance in electrical components, which is not the operational principle of a transformer. Capacitive coupling typically involves the transfer of energy through electric fields rather than magnetic fields, making it distinct from how transformers function. Linear transformation relates more to mathematical concepts or signal processing, rather than the physical principles employed by transformers in electrical engineering. Hence, the focus on mutual inductance in the operational principle of a transformer is crucial to its design and application in electric motor control systems.