The stroboscopic effect was observed and documented as early as the early 19th century by the English physician Peter Marc Roget. His observations led to the development of stroboscopy, an optical method for making fast, periodic motion sequences visible.
This works, for example, by means of a rotating disk with slits or by illuminating the object with a sequence of short light flashes. The resulting stroboscopic effect makes moving objects appear to be at rest or in a different state of motion than they actually are. On the one hand, this can be used to make fast-moving processes appear slowed down or as a still image.
On the other hand, the stroboscopic effect poses a great danger. Flickering lighting can lead to incorrect perception or estimation of rotation or direction of rotation when working with machines with moving parts, as the periodic light effect is superimposed on the periodic motion of rotating or reciprocating machine parts. To avoid accidents that may result, lighting systems should be designed to avoid pulsing of the light. This is done by using less flickering light sources or by operating discharge lamps with electronic ballasts. The use of DC-supplied incandescent lamps or the operation of incandescent lamps with a high supply voltage is also suitable for avoiding dangerous stroboscopic effects.