4 ms·
I worry we’ll find the high speed strobe almost all LEDs emit are harmful for humans or animals. We’re told they strobe too fast for us to perceive (sometimes
by nostromo 3y ago
I worry we’ll find the high speed strobe almost all LEDs emit are harmful for humans or animals. We’re told they strobe too fast for us to perceive (sometimes true, sometimes not). But unperceptible doesn’t mean it’s not harmful.
A lot of people that use their iPhone’s slow motion video function indoors at night are surprised to see they are surrounded by a disco of blinking lights.
- brookst 3y agoNot new at all. Many of those blinking lights are not even LEDs.
- Syonyk 3y agoTry it. A 240fps high speed is more than enough to observe a variety of LED flickering behaviors. Some flicker none (Bedtime Bulb is remarkable in the lack of flicker), some flicker at high enough frequency you can't really make out details, and others are just... gross.
- tourmalinetaco 3y agoIs this even an LED exclusive problem? I was taught this is mainly due to alternating current, and is seen in filaments as well.
- nostromo 3y agoFilaments are slow to respond to alternating current. So they do wobble in brightness a bit, but they do not blink like an LED does, which fluctuates between 100% off and on.
- Syonyk 3y agoLEDs flicker differently. An incandescent has 10-15% brightness flicker at 120Hz. LEDs... vary. Some flicker a lot harder at 120Hz, some (mostly LED Christmas lights) are awful and flicker at 60Hz with a 50% duty cycle because they're a single diode rectifier. Most LEDs flicker far faster, in the kHz range, which is theoretically beyond human impact, but we don't have many studies on it. Incandescent flicker is also related to bulb wattage. A higher wattage bulb, with a thicker filament, will flicker less because it has more thermal inertia.