“This way of checking the quality of lighting in our home, or anywhere else, is extremely simple, cheap, and mobile
Light flickering can be a common issue and may occur with various types of bulbs, including incandescent, fluorescent, and LED lights. Numerous studies have shown that flickering, although high frequency and then totally invisible, It can also cause headaches, eyestrain and nausea. Incandescent, halogen or fluorescent lamps (as well as LED if poorly designed), turn on and off a hundred times a second and produce light with a flicker at a certain frequency. Here are some general reasons why lights might flicker and potential solutions:
Faulty or Loose Switch,
Voltage Fluctuations
Dimmer Switch Compatibility
Loose Wiring or Poor Connections
And most often with LED lamps, LED Driver Issues
The shape of the electricity in the public network has a frequency of 50 Hz (or 60 Hz in some countries).
Old incandescent bulbs are powered directly from the mains so they flash at the same frequency of 50Hz, but their flicker is imperceptible because they are actually heaters, and can not quickly follow the change, which in this case is a positive feature, and there is not visible flickering. In some cases, LED bulbs were powered by a half-wave voltage, obtained by using a one diode, and their flicker is at a frequency of 50 Hz and with high intensity, because LEDs are electronic elements that currently monitor the change of voltage, unlike incandescent bulbs. Even today some lamps use this principle, and we should certainly avoid them. Now consider a type of high power LED used in spotlight. In this type of LED, the power supply is located on the cooling plate itself, and probably uses the “pulse width modulation” principle without a filter capacitor. Тhe signal is almost rectangular with a large difference between the minimum and maximum amplitude. This type of lamp should be avoided in the home, and can only be used for outdoor lighting.
Commercial flickering measuring instruments are very expensive, from a few hundred to several thousand dollars.”