Debunking the Myth: Do LED Lights Flicker? Get the Definitive Answer Here!

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Discussion Overview

The discussion revolves around the flickering of LED lights, exploring whether they flicker under various power supply conditions. Participants examine the effects of different types of power supplies, including rectified DC and AC, and the implications for household and automotive lighting. The conversation includes technical explanations, personal observations, and anecdotal evidence regarding flicker perception.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that LEDs driven by a well-regulated DC power supply do not flicker, while others argue that unregulated AC supplies can cause flickering at the frequency of the AC source.
  • It is noted that flickering may not be perceptible to humans due to the rapid rate at which it occurs, typically at 60 Hz or higher.
  • A participant mentions that decorative LED lights are intentionally designed to flicker.
  • Some participants share personal experiences and tests indicating that all types of household lamps, including LEDs, may flicker, though they may not be detectable without specialized equipment.
  • There is discussion about the role of smoothing capacitors in reducing flicker and how this might vary between different lighting applications.
  • One participant highlights that the flicker perception can vary widely among individuals, suggesting a physiological aspect to flicker detection.
  • Concerns are raised about the design of consumer LED products, which may prioritize cost over flicker reduction, leading to noticeable flicker in some cases.
  • Some participants mention that incandescent lights also exhibit flicker, albeit at a level that is often imperceptible to the naked eye.

Areas of Agreement / Disagreement

Participants express a range of views on whether LED lights flicker and under what conditions. There is no consensus on the extent of flicker in different types of lighting, and the discussion remains unresolved regarding the impact of various power supplies on flicker perception.

Contextual Notes

Limitations include varying definitions of flicker, the dependence on specific power supply designs, and the subjective nature of flicker perception among individuals. Some technical details about LED driver circuits and their operation are also mentioned but not fully resolved.

  • #31
anorlunda said:
The OP was asking about LED light bulbs indoors.
I suspect the underdesigned input side caps. These are some 10-47uF sized high voltage electrolytic caps, and while the LED driver will try its best to maintain a constant current through the LED string with high frequency switching, some of the 100 or 120Hz (graetz-doubled line frequency) may still slip through.
 
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  • #32
Merlin3189 said:
Nice. But I wonder how you know it is the Leds flickering rather than camera strobe?
(I don't actually know whether digital cameras have a strobe effect like the old movie cameras did.)
I'm aware of that , this is why its difficult to grasp the whole effect from a screen. when you see it with the naked eye it makes stuff look like a hologram but on a screen it just looks like frame rate effects here is a more recent video of mine ...
 
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  • #33
dlgoff said:
Here's a "Why LED's flicker" I found by Google searching:

https://www.nbpower.com/blog/en/posts/2018/june/why-led-s-flicker-and-how-to-stop-it/
I've done many tests using LED strip lights running off different levels of AC voltage using a Auto-Transformer and controlling how much AC volts go into the strip. It was kinda surprising how much AC voltage they could handle before burning out at around 60-70 volts AC. Even though they could run on 30-40 volts AC but at this voltage the heat build up that gets put out by the strip increases dramatically to the point where the PCP pipe I had wrapped the LEDs around began getting soft and to in a sense melt the PCP pipe from the excess heat. The LED lights though to my surprise could handle the heat very well and only burnt out when AC voltage was apply at too high a level and cause the diode to pop and come on only very dimmly after but still not completely burnt out. This tolerance is only done with LED strip lights that have semi-conductor chips in them providing resistance for the DC current. These resistors is what allow for the AC voltage to power the strip without burning out the LED completely. if AC voltage is apply to LEDs that don't have resistors in its circuit will burn then out at 3-5 volts. I know from tests I've done. But strip lights with resistor chips in them can run on lower voltages of AC and when doing so give off a very holographic ghost like blinking effect behind any object that moves like a ghost blinking tail following behind the object moving on what ever these LED lights shine on. This effect is really cool to see with the naked eye and I think could have potential for stage performers or break dancing anything like that. I have yet to test different frequencies with the LED strip lights to see if I can shorten or extend the tail of blinking flashes that follows behind the objects moving when using these LED strip lights but have not gotten to that point yet. Finding time to work on this stuff can be difficult sometimes...
 
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