In a purely capacitive circuit, how does the current behave in relation to the voltage?

In a purely capacitive circuit, the behavior of current in relation to voltage is characterized by the current leading the voltage. This is due to the nature of capacitors, which store energy in an electric field when charged. When an alternating voltage is applied to a capacitor, the capacitor begins to charge and discharge.

As the voltage increases, the current flows into the capacitor, causing it to charge. During this phase, the current reaches its peak before the voltage does, which is indicative of the current leading the voltage. This phase difference is essential for understanding how capacitors interact with alternating currents and is a fundamental concept in AC circuit analysis. The current peaks before the voltage because it takes time for the capacitor to change its charge state, effectively creating a lead in the phase relationship between current and voltage.

Thus, the correct understanding of this dynamic in a purely capacitive circuit is that the current indeed leads the voltage.