When does current lead voltage in devices?

The correct answer is capacitive devices because these devices store electrical energy in an electric field, which creates a phase shift between voltage and current. In capacitive devices, the current leads the voltage; this is attributed to the way capacitors charge and discharge.

When an AC voltage is applied to a capacitor, the current reaches its maximum value before the voltage does. This occurs because the capacitor allows current to flow as it charges up, and the change in the electric field inside the capacitor can cause the current to increase before the voltage across it has peaked.

In contrast, inductive devices operate on a different principle where the current lags behind the voltage due to the magnetic fields created in coils or inductors. Transformers are essentially inductive components as they rely on the principle of electromagnetic induction to transfer energy between circuits, leading to a lag of current compared to voltage.

Hence, the unique behavior of capacitive devices, where the current leads the voltage, clearly establishes why this is the correct answer.