Välähdystaajuus

Välähdystaajuus, often translated as flicker frequency or flash frequency, refers to the rate at which a light source, typically a fluorescent lamp or older display, cycles on and off. This rapid switching is often imperceptible to the human eye, creating the illusion of continuous light. However, under certain conditions, such as fatigue or when viewed indirectly, the flicker can become noticeable as a subtle pulsation or shimmering.

The frequency of these flashes is determined by the electrical power supply of the region. In countries with a 50 Hz power grid, the flicker frequency is usually around 100 Hz, as the lamp turns on and off twice per AC cycle. In 60 Hz regions, the flicker frequency is typically 120 Hz. This higher frequency makes the flicker less likely to be perceived.

While modern technologies like LED lighting and higher refresh rate displays have significantly reduced or eliminated perceptible flicker, older technologies, particularly certain types of fluorescent lighting, could produce flicker that some individuals found distracting or even caused discomfort, headaches, or eye strain. The study of flicker frequency and its effects is relevant in fields such as lighting design, display technology, and visual ergonomics.