When a purely resistive load is applied, how does current behave in relation to voltage?

In an AC circuit with a purely resistive load, the current is in phase with the voltage. This means that both the voltage and current waveforms reach their maximum and minimum values at the same time. There is no phase difference between the two, which is indicative of a purely resistive load, as resistors do not store energy as inductive or capacitive components do.

When the resistive load is applied, it converts electrical energy into thermal energy without any time delay. This behavior allows the current to directly follow the voltage changes, reflecting that they rise and fall together. Thus, for purely resistive loads, the relationship is characterized by a cosine function for both voltage and current, effectively showing that they are synchronous in their cycles.

In circuits that involve inductance or capacitance, the phase relationship between voltage and current changes, leading to either the current lagging behind or leading the voltage. However, for a purely resistive load, the current maintaining phase with the voltage is a fundamental characteristic of how resistors operate in an AC circuit.