The same happens with my tablet if I set the brightness to the minumum on Android. If I see it a little above the minimum, the buzzing stops. I guess it is because of their pwm implementation, which may use a lower refresh frequency when the screen is at lowest..
Thank you very much for your answer, Veaceslav. It confirms the issue doesn’t relate to my device, but to the model.
The solution I’ve found is to set brightness at 25% and then use an app that creates a filter to reduce brightness (Screen Filter). The result is fairly good, but I think the battery drain is highter than setting brightness to 0%. Does anybody knows a better app for this, or maybe a better solution?
Well, I also noticed the buzzing in windows at 0%. The problem is that windows will increment your brightness to only 4 levels: 0%, 25%, 50%, 100%.
But you can go to settings and set it to other values. I managed to get it at 16% without buzzing. I don’t think that there is a better solution, because it relies in hardware(google pwm to understand how do they lower the brightness)