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Recent Innovations forced mostly by newer and stricter government regulations have brought us through extremely unreliable CFL light bulbs from the old incandescent light bulbs to these very expensive yet aledged long life LEDs. So far I'm okay with these LEDs especially how cool to the touch they are. But I have been noticing a high frequency flash involved. One can see the flash by using a fidget spinner and observing the light and area it illuminates. Is this something we should be be thinking about as far as health issues may be concerned?

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closed as primarily opinion-based by PeterJ, laptop2d, DoxyLover, winny, Dave Tweed Sep 30 '17 at 11:44

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Probably not but it plays merry hell with my infra-red remote controls. \$\endgroup\$ – Brian Drummond Sep 11 '17 at 22:13
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    \$\begingroup\$ If you're noticing a flashing, chances are it's not that high of a frequency, maybe 100-120Hz depending on your locale. \$\endgroup\$ – W5VO Sep 11 '17 at 22:17
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    \$\begingroup\$ Really @BrianDrummond? I had not heard that. \$\endgroup\$ – Trevor_G Sep 11 '17 at 22:24
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    \$\begingroup\$ @ali that would be a bad bet in deciding a 5 or 10 year warranty \$\endgroup\$ – Passerby Sep 12 '17 at 0:54
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    \$\begingroup\$ Feit is cheap. Cree comes with 5 year if I recall. You have your receipt right, get a warranty exchange \$\endgroup\$ – Passerby Sep 12 '17 at 5:29
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Continuous exposure to flickering light is known to cause myopia in developing eyes (here's a clinical study in guinea pigs, albeit with the frequency 2 orders of magnitude lower than you'd expect in LED lights). It was also the primary reason for CRTs to have ever-increasing refresh rate, which is close to the flickering frequency of LED lights. Apparently, the damage is reduced as the frequency increases, at least I can certainly assert that I've spent more than 4 weeks in front of a CRT as a kid, and I didn't get myopia yet.

Note that flickering is only present in the cheapest devices which lack any smoothing or regulation circuit, so if your LED lights have noticeable flickering, just go for a better brand. Those will have LEDs driven either constantly, or at much higher frequency.

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LED driver circuitry can involve switching the diode ON and OFF over time, but it is not a requirement for LEDs in order to work. Higher end lamps will probably tend to switch in unnoticeable frequencies or maintain the diode ON all the time. Eyes on the other hand depend on chemical reactions to sense light, these reactions take a little while to happen so your body can't tell the difference between a brighter flashing light and a dimmer steady-ON light if frequency is high enough. There are no proven detrimental effects of high frequency flashing lights in our physiology. Experiments to test these ideas are simple and have been conducted. PubMed is a well known journal where you can search for articles regarding the subject!

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I'm sure someone will swear they cause migraines or worse.. But whatever health issues they may just represent has to be better than all the mercury in the CFLs.

Any flashing you may see though is more a characteristic of how the LEDs are driven, not the LED's themselves.

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  • \$\begingroup\$ There are many makers of LED bulbs. I believe the cheapest way to control the average current across the LED is PWM. And no one knows which control frequency they would choose to get their bulb running until a user forget where he put sales receipts to claim the warranty. So very likely there are LED bulbs that flick like hell. \$\endgroup\$ – Ale..chenski Sep 12 '17 at 0:15
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    \$\begingroup\$ Mercury in the CFLs has zero impact of health, unless the OP keeps smashing light bulbs in his house. \$\endgroup\$ – Dmitry Grigoryev Sep 12 '17 at 12:06
  • \$\begingroup\$ @DmitryGrigoryev yes I was more thinking about the proper disposal issues. Around here, you are supposed to take them to the waste disposal station to be properly handled, but I seriously doubt anyone does even if they are aware of it. SO instead the Mg is being added to the landfill / environment. \$\endgroup\$ – Trevor_G Sep 12 '17 at 13:57

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