SACA Motor Control Practice Exam – Complete Study Resource 2025

The fundamental principle of a transformer is based on mutual inductance, which is a key concept in the operation of transformers. Mutual inductance refers to the process by which a change in current in one coil (the primary winding) induces a voltage in another coil (the secondary winding) through a shared magnetic field. This interaction allows transformers to transfer electrical energy between circuits while stepping voltage levels up or down.

Transformers rely on alternating current (AC) because it creates a changing magnetic field, which is essential for inducing voltage in the secondary coil. When current flows through the primary winding, it generates a magnetic field, and as this magnetic field fluctuates due to the alternating current, it passes through the secondary winding, inducing a voltage there according to Faraday’s law of electromagnetic induction.

While electromagnetic induction is related to the operation of transformers and is indeed a broader concept that encompasses how transformers work, mutual inductance specifically denotes the interaction between the primary and secondary coils that is central to transformer function. Thus, the focus on mutual inductance highlights the unique relationship and energy exchange between the coils that makes a transformer effective for voltage transformation.