This is the 100HZ ripple of fluorescent lamp stroboscopic, which only appears in fluorescent lamp circuits with inductive ballasts, because the mains frequency is 50 Hz, resulting in 100 flashes per second. Although the fluorescent powder on the inner wall of the lamp tube has a certain afterglow time, it will quickly darken even within one hundredth of a second, leading to stroboscopic phenomenon. Although people's eyes are not easy to detect, long-term exposure to this light source is harmful to their eyes, especially when using old fluorescent lamps, and this stroboscopic effect is more obvious. Injury to eyes: When working and studying under a stroboscopic light source with changing light intensity, the visual system needs to constantly adjust the pupil size of the eyeball to ensure the stability of retinal illumination and the clarity of imaging. In this way, working in this environment for a long time will definitely make the pupil sphincter tired due to excessive use, thus causing damage to the optical system of the eyeball. Secondly, because the adjustment frequency of the pupil sphincter can't keep up with the speed of light intensity flicker, the light intensity reaching the retina will inevitably fluctuate. In this visual environment, in order to adapt to this changing light intensity, the retina needs to constantly adjust the dynamic distribution of its neural network activities in space and time, so as to keep the retina in different adaptive States to adapt to different light intensities. Therefore, working and studying under the flickering light source will inevitably lead to adverse consequences due to the frequent activities of retinal neurons, such as changes in the pH value of the retina and the accumulation of harmful substances in the metabolites of neurons, thus causing damage to the retina. In addition, the light intensity flicker will also interfere with the processing and comprehensive analysis of images by the visual center, thus forming glare and optical illusion. If the factory workshop has stroboscopic effect, the harm is very serious, which will make people have an illusion. For example, an object that rotates at a normal high speed will be considered to rotate slowly or even reverse, and a ball that flies at a high speed will be considered to be intermittent. For example, in a workshop with rotating objects, when the rotating frequency is an integer multiple of the flashing frequency of lights, the rotating objects look like static, which often causes accidents. Do a simple test with the photo state of the mobile phone or the camera state, and the stroboscopic flicker of the ordinary desk lamp or fluorescent lamp on the screen is obviously visible.