Primary Coil: The primary coil is the input winding of a transformer that is connected to the source of alternating current. It induces a changing magnetic field that is transferred to the secondary coil.
Mutual Inductance: Mutual inductance is the property that allows the changing magnetic field in the primary coil to induce a voltage in the secondary coil, enabling the transformation of voltage and current levels.
Transformer Ratio: The transformer ratio is the ratio of the number of turns in the secondary coil to the number of turns in the primary coil, which determines the voltage and current transformation between the input and output.