What is the phase difference between voltage and current in a purely resistive AC circuit?

In a purely resistive alternating current (AC) circuit, the relationship between voltage and current is characterized by their phase difference. In this case, voltage and current are in phase, which means they reach their maximum and minimum values simultaneously. This situation is represented by a phase difference of 0 degrees.

When dealing with resistive components, such as resistors, all the supplied energy is converted into heat, and there is no reactive component to cause a phase shift. Therefore, in a purely resistive circuit, the characteristics of voltage and current are perfectly aligned, resulting in both waveforms oscillating together in time. This is a fundamental principle in AC circuit theory that is critical for understanding how resistive loads behave in electrical systems.

In contrast, other types of circuits, such as those with inductive or capacitive components, do exhibit phase shifts of 90 degrees or even 180 degrees, but in a purely resistive circuit, this alignment denotes a phase difference of 0 degrees.