31–40 of 70 posts
Earlier quoted context omitted.
Me too - constant headaches from fluorescent lights, none from LED. I buy the less efficient full-spectrum LED lights which have a phosphor. The phosphor probably filters the underlying LED flicker.
Yeah, I think my Ikea ones are phosphor, the Philips Hue are RGB though and still fine.
I've had this problem and decided to test the problem away. Used a Vishay visible spectrum phototransistor and my scope. Think it was a BPV11 transistor. Philips bulbs are 100% clean. Poundland ones are not. Cheap no brand ones from Amazon are not. The latter two have a 100Hz output. I suspect the hatred for LED bulbs stems from the cheap ones which use the lowest cost solution to get mains voltage into a constant cu…
By "100% clean" do you mean no flicker, ie. they use the more expensive components? I invested in Philips LED bulbs about a year ago and honestly I can't fault them at all. I consider myself to be sensitive to things like flickering. It doesn't usually give me a headache, but it will make me notice it to the point of distracting me. I was so happy to find that the Philips LEDs were almost just like old-fashioned bulb…
What gets me are side-lights on cars that flicker. Cars have DC electric systems in the first place. Where did the Audi engineers find 100 Hz to run the LEDs from? I guess there's a switch mode power supply to convert down from 12 V to something lower that the LEDs need. But AFAIK, switch mode power supplies don't switch at 100 Hz. I'm pretty sure you could show by experiment that flickering car side-lights are distr…
I suspect its not the PSU, its the PWM for the dimming. compared to actually lowering the voltage/current of a LED/light/other its far simpler and cheaper just to turn it off and on again at varying duty cycles/ frequency.
Weird, I've never had issues with LED bulbs, but I routinely have headaches from fluorescent. Maybe I've just lucked out with my specific bulbs being higher quality (Ikea, Philips Hue). I imagine color spectrum is a large part too.
If I don't move it's ok, but as soon as I look around I see a pattern of black and white areas from LED light.
Most of my led lighting is dimmable, and takes noticeable time to go dark after I flip the switch to off. The ones that actually have dimmer switches installed also take noticeable time to come on when set as dim as possible. I seriously doubt that those bulbs have flicker problems.
I've had this problem and decided to test the problem away. Used a Vishay visible spectrum phototransistor and my scope. Think it was a BPV11 transistor. Philips bulbs are 100% clean. Poundland ones are not. Cheap no brand ones from Amazon are not. The latter two have a 100Hz output. I suspect the hatred for LED bulbs stems from the cheap ones which use the lowest cost solution to get mains voltage into a constant cu…
But then wouldn't our 60Hz screens have a much bigger impact on office workers than the lights above them?
Earlier quoted context omitted.
Another issue is that many LEDs have peaky spectra. This makes cool white harsh and warm white dingy. This isn't limited to cheap products, as producing a fuller spectrum with LEDs is less efficient. I'll take the efficiency hit for better light; the most common measure used, printed on the packaging of some bulbs is CRI (color rendering index). It's based on blackbody radiation, so incandescent bulbs and sunlight bo…
Agreed! It took several tries to get LEDs which worked well for vanity (i.e. Mirror) lighting. I thought it was a simple matter of color temperature - so wrong! High CRI strip LED arrays are surprisingly hard to find. The end result was worth it though - skin looks natural, and the nearest commercial version is upwards of $800 - and I'm not entirely sure they got the CRI right.
[1] https://electronics.stackexchange.com/questions/32675/why-do...
From experience there's a massive difference in the quality of light from a cheap LED bulb to an expensive one which I don't think is something that the bulk of consumers are aware of yet.
For those in the UK, I can recommend Screwfix LEDs. They seem to be lasting for me, don't flicker and are relatively cheap at £2/bulb http://www.screwfix.com/p/lap-gls-led-light-bulbs-white-bc-9...