points by winrid 3 days ago | 0 comments
This. It likely depends on the driving technology. Some repell me too :P
Note you can make LEDs dim without PWM via constant current drivers, just less efficient as the duty cycle is 100%, they look much nicer though
[–] nik282000 3 days ago
[–] skew-aberration 3 days ago
How do you know the difference? Constant current is almost certainly a PWM controlled buck/boost regulator. The flicker is attenuated by inductance, more or less depending on the design.
[–] nik282000 3 days ago
I guess the distinction is 'filtered' vs 'unfiltered' then. If you look at the lights that fail early using a high framerate camera (1k fps) they flicker between full brightness and fully off. The lights that last longer have some ripple but its 5-10% brightness.
[–] dchristian 3 days ago
Use a fidget spinner to see the difference. Spin up a 3 lobe fidget spinner and catch the reflection of the LED on it's surface. As the speed changes, a flickering LED will freeze the motion of the spinner. Even more fun with spinners :-).
Yes, adding an inductor will fix the problem, but that costs money. Not enough customers are complaining about the light flicker to justify the higher price.
anecdote: I work in a factory, we have thousands of light fixtures. The older constant current LED fixtures have lasted a decade, the new PWM driven lights have had a ~1% failure rate.