The scientific reason you don’t like LED bulbs – and the simple way to fix them
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Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#2Weird, 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.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#3Weird, 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.
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.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#4From 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.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#5Weird, 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.
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.
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Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#6Most 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.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#7Weird, 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.
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.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#8I'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 current which is usually a capacitive dropper and rectifier with an inadequate smoothing cap.
Really as always with these things, buy the best you can.
Also the cheaper ones seem to have a blue/white tone whereas the expensive ones have a yellow/white tone and are warmer. This helps the eyes.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#9I hate it when LED light output isn't continuous or visibly flickery, especially when it's from LED lights that are on (or are visible from) moving objects -- such as LED taillights on automobiles or in-road lane lights. All the eye movement (or object movement) makes the flicker even more flagrant :(
I remember extremely flickery lane lights on the leftmost lane markers on California's infamous SR 110, on the northbound direction (towards Pasadena) in the tunnels (the ones right before the left-exit to I-5 north).
Good fluorescent bulbs will have electronic ballasts (the driving circuit) that supply current to the bulb with a higher frequency (in the low kilohertz) than the time response of the bulb's phosphor. Thus, any sort of flicker gets low-pass filtered and isn't significantly noticeable in the output light.
Even with a subpar magnetic ballast that drives the bulb with line frequency, the phosphor never gets close to fully extinguishing -- so there is flicker, but the instantaneous light output never gets less than, say, half the maximum instantaneous light output. Look on page 3 of http://www.usailighting.com/stuff/contentmgr/files/1/e18f88d... for some instantaneous light vs time graphs for fluorescent bulbs.
LEDs have a much higher frequency response (in the tens of megahertz, easily) -- they respond quicker and more faithfully replicate their electrical drive signal as light output. You can see on page 4 of that report how violently jagged the LED's light/time plots can get.
If the manufacturer didn't want to include adequate filter capacitors in the LED's driver because of cost/reliability concerns, well, I hope your eyes enjoy that signal because the LED, unlike the fluorescent bulb, isn't going to smooth it out.
Re: The scientific reason you don’t like LED bulbs – and the simple way to fix them
#10I'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…
I'd be shocked if the flicker went to 0% as this article seems to imply ("because LED flickering is even more pronounced, with the light dimming by 100% rather than the roughly 35% of fluorescent lamps") -- and I doubt the flicker for fluorescent lamps is at RMS.
There's _gotta_ be at least a smoothing capacitor after the bridge rectifier (are they actually that cheap to omit one?!). I can't find a single LED driver circuit schematic online without the low pass filter.