What type of loads creates a nonsinusoidal waveform?

Nonlinear loads create nonsinusoidal waveforms because they draw current in a non-linear manner relative to the voltage supplied. In electrical circuits, linear loads, such as resistors, consume power in a predictable manner, maintaining a direct proportional relationship between voltage and current, which leads to sinusoidal waveforms in steady-state operation.

On the other hand, nonlinear loads—examples of which include diode rectifiers, switching power supplies, and certain types of electronic devices—do not maintain this proportionality. As a result, they can produce harmonics and distortions in the current waveform, leading to shapes that deviate from pure sine waves. These distortions can be represented as additional frequencies beyond the fundamental frequency, creating a complex waveform characterized by sharp spikes or flat sections, unlike the smooth transitions seen in sinusoidal waveforms.

While capacitive and inductive loads are also essential components in circuits, they typically influence phase relationships but do not inherently cause the waveform to become nonsinusoidal unless combined with nonlinear characteristics. Therefore, the defining trait of nonlinear loads is what fundamentally distinguishes their waveform characteristics from those of linear loads.