4 ms·

LED lights mess with my brain. The flashing is problematic.

by IceHegel 3y ago

zamadatix 3y ago
Flicker isn't intrinsic to LEDs, just cheap ones people flock to.
- dabluecaboose 3y ago
  Flicker is intrinsic to LEDs. It's how their brightness is modulated.
  - zamadatix 3y ago
    Not all LEDs are even dimmable, either. For something like streetlamps, which are typically either full off/on, paying extra for brighter dimmables to then run them at a less bright setting doesn't sound an appealing option anyways. But while we're on the topic of dimmables anyways, quality dimmables should have a switching frequency >1 KHz which is a different kind of flickering than e.g. low quality drivers which flicker at a perceivable rate (50hz/60 hz or double depending on the design).
    - seiferteric 3y ago
      Seems like if there is more than 1 LED, you could just drive them at different phases like at a minimum you could have half could be driven 90 degrees out of phase to practically eliminate flicker.
      - zamadatix 3y ago
        Just smoothing the rectification is cheaper and prevents the light from looki bc weird. It also makes your light brighter vs letting elements dip in cycles.
  - mindslight 3y ago
    Flicker isn't intrinsic to LEDs themselves, but rather driver circuits that are efficient and cheap, doubly so for ones that run off low frequency AC mains power. To design a circuit that didn't flicker, first you'd need bulk capacitance to ride out the 100/120Hz AC waveform dips, especially if you didn't want the device to draw peak current around the zero crossing. Then you'd need a high switching frequency and either enough bulk inductance to ride out that off period, or a bunch of bulk capacitance and some wasted power to control the current.
  - smat 3y ago
    You can modulate the brightness without flicker, you can try it yourself with a lab power supply. It is just that filtering the output of the regulator is “expensive” as you need a relatively large capacitor. If this is omitted in combination with a low frequency PWM, you will experience flicker.
  - Panzer04 3y ago
    Not if they are designed halfway reasonably. Any good LED should be driven with a PWM driver at high frequency, with low frequency mains AC (the source of the flicker) completely separated from the LED. This costs slightly more than alternative methods that use mains directly and don't properly isolate the AC component :(
expertentipp 3y ago
Motion detector and dimming through discrete brightness levels make me hate this technology. I hate when stingy idiots start to cut costs, they purchase the cheapest crappiest plastic and install it everywhere.

LED lights mess with my brain. The flashing is problematic.

zamadatix 3y ago

Flicker isn't intrinsic to LEDs, just cheap ones people flock to.

dabluecaboose 3y ago
Flicker is intrinsic to LEDs. It's how their brightness is modulated.
- zamadatix 3y ago
  Not all LEDs are even dimmable, either. For something like streetlamps, which are typically either full off/on, paying extra for brighter dimmables to then run them at a less bright setting doesn't sound an appealing option anyways. But while we're on the topic of dimmables anyways, quality dimmables should have a switching frequency >1 KHz which is a different kind of flickering than e.g. low quality drivers which flicker at a perceivable rate (50hz/60 hz or double depending on the design).
  - seiferteric 3y ago
    Seems like if there is more than 1 LED, you could just drive them at different phases like at a minimum you could have half could be driven 90 degrees out of phase to practically eliminate flicker.
    - zamadatix 3y ago
      Just smoothing the rectification is cheaper and prevents the light from looki bc weird. It also makes your light brighter vs letting elements dip in cycles.
- mindslight 3y ago
  Flicker isn't intrinsic to LEDs themselves, but rather driver circuits that are efficient and cheap, doubly so for ones that run off low frequency AC mains power. To design a circuit that didn't flicker, first you'd need bulk capacitance to ride out the 100/120Hz AC waveform dips, especially if you didn't want the device to draw peak current around the zero crossing. Then you'd need a high switching frequency and either enough bulk inductance to ride out that off period, or a bunch of bulk capacitance and some wasted power to control the current.
- smat 3y ago
  You can modulate the brightness without flicker, you can try it yourself with a lab power supply. It is just that filtering the output of the regulator is “expensive” as you need a relatively large capacitor. If this is omitted in combination with a low frequency PWM, you will experience flicker.
- Panzer04 3y ago
  Not if they are designed halfway reasonably. Any good LED should be driven with a PWM driver at high frequency, with low frequency mains AC (the source of the flicker) completely separated from the LED. This costs slightly more than alternative methods that use mains directly and don't properly isolate the AC component :(

expertentipp 3y ago

Motion detector and dimming through discrete brightness levels make me hate this technology. I hate when stingy idiots start to cut costs, they purchase the cheapest crappiest plastic and install it everywhere.