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why do LED bulbs flicker now. They use to be stable
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BrokenYugo:
Mostly just race to the bottom modern corporate management BS. The Phillips ultra whatever do make nice light, warm when dimmed, etc. Closest to a real tungsten lamp I've ever seen, including one failing in under a month, in an open fixture, looked like a driver failure.

The GE HD bulbs ran hot and 75% died in under a year, they didn't even silicone the diffusers on good.

Most reliable I've seen were "Earth bulb", one of the first low cost options ($5 each), oldest I have are probably a decade old, some very high hour (noticably dim but still working), only one failure, recently, big heavy buck converter driver. Also the 100 watt equivalent Dollar Tree bulbs (hard to beat $1.25 for 1500 lumen 14 watts), I use those in utility/work areas to brighten them up, haven't killed one yet, even have a pair in an outdoor security light, only protected from direct rain, other than some yellowing of the diffusers they're fine 2 years later. Also being the linear regulator type they're dead quiet.
wraper:
In EU it's now illegal to sell any bulbs that significantly flicker, so any bulb sold here is at least half-decent in this regard. There is no such regulation for floodlights though and most of them are flickering garbage. Also each LED bulb must have standardized information sheet where you can check actual flicker specs. It's often present on manufacturer website and online stores. However if it's not there, there is also public database https://eprel.ec.europa.eu/screen/product/lightsources where you can find every bulb legally sold here as long as you know model identifier than can be found on the box. Although what's not helpful about this is that manufacturers often just specify max permissible flicker and stroboscopic effect specs (Pst/SVM) instead of actual figure.
floobydust:

--- Quote from: BrokenYugo on March 11, 2024, 02:58:11 am ---Mostly just race to the bottom modern corporate management BS. [...]
--- End quote ---

It's worse than that - you have Feit, Nichia, Seoul Semi, Cree, Ledvance etc. all suing each other over patent infringement. For years now.
Even that's not enough - then they also sue the retailers like Wal-Mart, Home Depot, ACE Hardware etc. for selling the "infringing" products.  :palm:
I can't imagine how to design a reasonable, decent LED bulb with so many patents on heatsinking and LED configuration. This nonsense needs to be open for the planet's good and instead we have blink blink blink blink boing landfill for these "50,000 hour life" electronics that incandescent bulbs end up giving them a run on lifetime.

Feit filament style LED lamp patent enforcement white not yellow. Jees
EPAIII:
Individual LEDs always have flickered. I used one years ago to replace a neon strobe light in a turntable. It worked like a charm. Individual LEDs can turn on and off at a rapid rate so all I had to do was drop the Voltage down and use a full wave rectifier WITH NO FILTERING. It "strobed" at 120 Hz, just like the original neon bulb did.

The assemblies that are commonly called LED bulbs today have a number of individual LEDs in them along with some circuitry that allows a 2 or 3 Volt DC device to function on 115 VAC. That circuitry would be what determines how much flicker you see, not the LEDs themselves. The LED bulb will draw around 50 mA, +/- depending on the exact equivalent Wattage. That current determines the size of the filter capacitor needed to smooth out the peaks and eliminate the flicker. If the manufacturer skimps on that capacitor, then you get flicker. Likewise if they use a choke instead of a capacitor.

It's that simple.
tom66:
Dimmable LED bulbs, in my experience, tend to flicker more.  This is because to add the dimming capability, they usually modulate the LED current to be in proportion to the input sine wave.  If a triac-chopped dimmer is used the result is a dimmed bulb = happy user.  However, any 'crap' on the power line will also be picked up by this circuit as it tends to have a quick response. 

I would suggest seeking out non-dimmable bulbs.  In my experience they are flicker-free, I have done high speed photography (480fps) under a new LED bulb from Costco and there was essentially no flicker visible from the bulb.  It unfortunately may only be something you can determine by experimentation as it is not usually marketed.
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