Flash reason of Led lamp

When people are in a lighting environment, they do not seem to be able to clearly feel flicker. In fact, except for warning flashing signs or lamp failures, people do not have much intuitive feelings about the concept of stroboscopic. When observing the rotating fan blades, you will find that the blades sometimes "stationary" and sometimes "rotating", and the driving car tires will also have this phenomenon, which can be explained as the visual persistence caused by the stroboscopic light source. 

     Cause of stroboscopic: stroboscopic of light source essentially means that the light emitted by the light source changes with a certain frequency and period over time, and changes with time between different brightness and color. If there is no suitable electronic circuit for the lamp driver, such as ballast, driver or power supply, the light source will produce stroboscopic. The greater the fluctuation of output luminous flux, the more serious the stroboscopic.

 The technical mechanism of stroboscopic generation includes not only the factors of power supply, but also the factors of technical performance of electric light source and unreasonable lighting design. For many lighting fixtures, the working current of the light source must fluctuate with the fluctuation of the input voltage, which directly causes the fluctuation of the light output to produce stroboscopic.

Stroboscopic criterion

 IEEE released IEEEPAR1789:2013 Draft Risk Assessment-Potential health effects of flicker from LED lighting in April 2013

 The judgment criteria for no stroboscopic file pair are:

 (1) The frequency is lower than 9Hz, and the limit value of undetectable fluctuation depth is 0.288%;

 (2) The frequency is in the range of 9-3120Hz, and the limit value of undetectable fluctuation depth is: frequency × 0.032%；

 (3) If the frequency is greater than 3120Hz, it is considered that there is no stroboscopic, and the assessment is exempted.