How is a sine wave characterized in AC voltage or current?

A sine wave is characterized by a smooth periodic oscillation, which is a fundamental aspect of alternating current (AC) voltage and current. This smooth oscillation reflects the continuous and cyclical nature of AC power, where the voltage rises and falls in a sinusoidal pattern.

The sine wave shape results from the mathematical function of sine, which perfectly describes how electrical energy transitions from positive to negative values in a predictable manner over time. This predictable oscillation allows for more efficient transmission and use of electrical energy. The gentle arcs of the sine wave contribute to lower stress on electrical equipment, reducing wear compared to waveforms with sharp changes.

In contrast, irregular fluctuations do not accurately represent the orderly nature of a sine wave, while constant voltage levels would describe a DC voltage rather than AC. Similarly, sharp peaks and troughs might suggest a waveform with distortion, which is not representative of the smooth, continuous variation inherent in a sine wave.