Zero crossing

It is a commonly used term in electronics, mathematics, acoustics, and image processing.

At audio frequencies, such as in modern consumer electronics like digital audio players, these effects are clearly audible, resulting in a 'zipping' sound when rapidly ramping the gain or a soft 'click' when a single gain change is made.

Early light dimmers and similar devices generated interference; later versions were designed to switch at the zero crossing.

In the field of industrial radiography, it is used as a simple method for the segmentation of potential defects.

[1] In the field of NLP, the rate of zero crossings observed in a spectrogram can be used to distinguish between certain phonemes such as fricatives, voiceless stops, and vowels.