How can a transformer with two windings change impedance?

Impedance (Z) is defined as the ratio of voltage to current in a circuit (Z = E / I). A transformer works by changing the voltage and current ratio between its primary and secondary windings based on its physical turns ratio. For instance, if a transformer steps down the voltage, it steps up the current proportionally to maintain the same overall power transfer. Because the voltage-to-current ratio is physically altered from one side to the other, the impedance presented at the primary is a mathematical transformation of the load impedance connected to the secondary. This unique property is why transformers are frequently used for impedance matching between different stages of a radio circuit.