An inductor can reduce voltage through its reactive impedance, which interacts with other circuit impedances to create an AC voltage drop. To measure an inductor's value, an LCR meter is the simplest tool, but alternatives like a signal generator, resistor, and oscilloscope can also be used. The phase shift observed in a resistor-inductor series circuit indicates when the inductor's reactance equals the resistor's value. Additionally, an inductor has a DC resistance that contributes to voltage drops in both AC and DC circuits. Understanding these principles is essential for effective circuit design and analysis.