Inductor in een AC-circuit

Consider an inductor connected across an alternating current voltage source. Using Kirchhoff's loop rule, the instantaneous voltage across the inductor can be determined.

Recalling the EMF across the inductor and considering the voltage around the loop as zero, the potential difference across the inductor can be established, and, by integrating the equation, the current through the inductor can be determined.

When the current and voltage quantities are plotted together, the current through the inductor lags the voltage across the inductor by a quarter of a cycle.

The relationships between instantaneous current and voltage can be represented using phasor diagrams, where both the phasors rotate at the same angular frequency, with the current phasor lagging behind the voltage phasor by π by 2 radian.

The ratio of peak voltage to peak current gives the inductive reactance of the inductor and is measured in ohms.

The inductive reactance of the inductor depends directly on the frequency of the alternating current source, with a high frequency leading to high inductive reactance and vice versa.