http://www.soraa.com/news_releases/52 I'd be interested seeing these in person. Furthermore my family owns a sailboat where the power is from DC batteries, my father purchased a LED light strip and hooked it up to the battery with a voltage knob making it a DC based flicker free LED light. I will write more about that later.

I used to buy a Panasonic LED bulb (5w 3000k soft white(350lm)) for reading. The yellowish color is not the same like an incandescent bulb. Just unnatural. The next day I returned the bulb. Yes it's flickering.

vinkenvvt Probably because it's a standard AC LED bulb

Anyone ind a place to purchase these/any flicer free LED? I want to run a test with one

ensete https://www.1000bulbs.com/category/soraa-led/ Not your standard light fixture though (is MR16 type), requires special driver.

I bought a Philips "Warm Glow" LED bulb. It flickers noticeably when driven by a Leviton universal dimmer. It seems solid to the naked eye when driven by a regular switch, but I didn't do any real PWM test yet. It makes the room look very washed out. My mom hated it. I guess the CRI is not very high. I wonder if a higher CRI bulb wouldn't make the room look so washed out, or if it is something intrinsic to LED bulbs which creates this effect.

I was using my iPhone 6 slowmo video (240 fps) feature to test out the PWM on my laptop screens, and noticed that all the LED bulbs in my office flickered pretty noticeably when playing back the video. I did't know if that was normal, so tried doing the same with other bulbs around the house. The florescent kitchen lights on electronic ballasts did not flicker, and neither did this one set of LED bulbs I put in the laundry room. Those LED bulbs that did not flicker, I happened to purchase from the local orange big box hardware store a few months ago, just cause they seemed different, are GE Bright Stik. More details on the GE website: http://www.gelighting.com/LightingWeb/na/solutions/led-lamps-and-modules/general-purpose/led-bright-stik.jsp I am not sure why these don't flicker, if they are really DC LEDs that have a converter built into the base, or maybe more advanced driver that smooths out the AC frequency dropouts that causes the flicker. I can post a video of this on youtube if anyone would like to see them.

megaladon999 I can post a video of this on youtube if anyone would like to see them. Please do - have you noticed any effect from them?

On a German website I found a big promising list of flicker free LED bulbs available at least in Germany: http://www.derlichtpeter.de/testergebnisse/ FfT means "flicker free techniqually", which should be our first choice. FfH means "flicker free for humans" which is worse. What they list is the so called "Compact flicker degree" (CFD). It looks complicated, and I have no idea what it really means. I didn't find an English Wikipedia entry for this. If someone finds a link which explains it in English, please share. Here he explains it in German: http://www.derlichtpeter.de/der-kompaktflimmergrad-cfd/ It seems there are a lot of ways to measure "flicker" degree. This CFD method is some complex formula as opposed to other "easy" ways like (MaxLight-MinLight)/MaxLight. I think the listed bulbs may operate in some other European countries, too. Not sure about other world regions. I think there are different technical standards (50 Hz vs 60 Hz and others...). But maybe some of you live in Europe so it may help you. Edit: He recently invented his measurement method himself, that's probably why it's not known yet internationally.

I bought a filament LED lamp that's in the list. It's a "Flicker free technically" one. My eyes hurt after a few minutes and I'm on the verge of a headache. Couldn't detect any flicker with Viso Systems app and didn't see any lines with 1/8000 camera shutter speed. Not sure what's going on. Either I'm a living high frequency detector or there's something else to light. This is not promising. I guess I should stockpile lots of incandescent bulbs.

KM Better to be safe than sorry.

Flicker free LED lights

ensete

Please do write your congressmen, and the president stating your desire to see the EISA restrictions removed. Ask them to reconsider The BULB Act (H.R. 2417) which removes these restrictions. This is a rare chance to get this done given the current administration we have.

PuffyCloud

KM After further investigation I found out that FfT bulbs are indeed flicker free. BUT these bulbs are very sensitive to the input electricity. If the input is not perfect these will flicker and will give you a headache like you mentioned.

You should test that "Flicker free technically" bulb you bought with a UPS(disconnected from the mains to generate perfect input for the bulb, otherwise you will get the same input as the mains) or with a Voltage Regulator.

Let me know this works.

JTL

PuffyCloud I'd imagine using a pure sine wave double conversion UPS would help as well,, vs one that just filters the input electricity and switches to battery during an outage.

degen

JTL I was investigating a UPS a while back because we had very bad voltage fluctuations at our house and I wanted to protect sensitive electronics. All of the Cyperpower units and all of the cheaper APC units either a) no pure sine wave output or b) not fast enough response time (4-8 ms in Cyperpower units to switch to battery power, but pro APC units had very good 2ms response, which is enough)

So if you want to regulate voltage through an APC you have to go for some of the more expensive and not entry level APC units.

JTL

degen I'm looking into this for the server rack in my garage 🙂

A bit pricey, but better than other options. The rackmount form factor increases the price just because it's for "business" use

http://excessups.ca/apc-smart-ups-rt-2000-surta2000rmxl2u-refurbished

degen

Apparently the UPS has 0 ms transfer time 😮

JTL

degen Because it always runs on battery, just constantly charging when power is plugged in.

Also works as an great surge protector because of that.

AGI

Has anyone tested these bulbs?

https://www.amazon.com/dp/B00MNU0BSQ

Customer care claims: "Our Finally light bulbs do not flicker. We have found customers who are sensitive to flicker and blue light really enjoy our light bulbs.".

JTL

AGI 99% of LED bulbs I've seen are crappy.

https://techsensitive.com/ has good reviews on the few that work but he is also Canadian so they would be 120v input

KM

PuffyCloud It sounds like you measured the "FfT" bulbs you tried. Did you measure any frequencies, and what exactly do you mean by "they go dark"? Like, really no light anymore? This might be very important, please reply.

I just measured my headache bulb which I still own with my oscilloscope setup. It is the "GreenAndCo TM-A19-6W-E27-W". I did not find frequencies other than 50 Hz and 100 Hz apart from very small fluctuations around 60 kHz. The latter are so small they only truly appear in the spectrum analysis (and only in AC mode). And the visible 100 Hz ripple appears to be very minor, too. At most 5 mV out of 600 mV total amplitude. That is well below 1 % difference. Can such small differences really cause headaches?

Solf

These Chinese Corn LED bulbs do flicker (pencil test), but they do not cause any eye strain for me.

Their parameters:
Voltage: 220V
LED type: SMD 5050 (square).
Color: warm white.
Image:

The bulbs which DO CAUSE eye strain to me immediately:

Brand: Philips
Voltage: 220V
MPN: 9290011717A (9W, warm white)
MPN: 9290011718A (6W, warm white)

Wrightpt1

Solf that bulb flickers at a rate of 220/2 = 110 times per second. I assume it's 220v AC current ur using. Most phones and screens if I remember correctly flicker anywhere been 800 to the thousands per second with PWM or oled.

KM

So I took my Fauser LiFli flicker detection device and went to a local IKEA store to measure the currently available bulbs in their lighting section. The vast majority of their lamps and bulbs flicker. However, some of them showed no sign of flicker on the device, which means the flicker must be below 1.5%*. So I bought those bulbs and took them home, measuring them with my oscilloscope setup. I tried to carefully measure even slightest fluctuations. Here are the results:

IKEA LUNNOM LED 600lm 5.5W 2200K E27 [703.545.64]: ~30% 100 Hz flicker that goes down to steady 0.41% 100 Hz flicker within ~7 seconds, no measurable high frequencies
IKEA LUNNOM LED 100lm 1W 2200K E27 [003.821.84]: borderline measurable 0.03% 50/100 Hz flicker (the 50 Hz part may be photodiode circuit noise), no measurable high frequencies
IKEA LEDARE LED 600lm 7W 2700K E27 [903.887.75]: 1.24% 100 Hz flicker, decreasing over time down to 0.29% 100 Hz flicker after some minutes, 0.33% 80-100 (varying) kHz DC ripple
IKEA LEDARE LED LED1719R6 400lm 5.3W 2700K E14 [503.658.27]: instant 0.18% 100 Hz flicker, no measurable high frequencies (total brightness decreases a little over time)
IKEA LUNNOM LED LED1641C2 200lm 2W 2200K E14 [403.545.32]: instant 0.06% 100 Hz flicker, no measurable high frequencies

Those bulbs have E14 and E27 sockets. They are compatible with 50/60 Hz 220/240V~. They seem to be available in other EU countries' IKEA stores, too. Maybe for those countries who have a different power network, they share the same flicker characteristics world-wide.

I must see over time how those bulbs work for me. What's great so far is they don't make me feel sick after some minutes like other LED bulbs did. Plus currently I'm under the impression that truly flicker-free LEDs don't exist as long as they are powered by AC.

* (I adjusted the device to show flicker percentage as (A-B)/A, where "A-B" is the difference between highest and lowest amplitude, and A is highest amplitude. My oscilloscope results are also calculated with this method.)

Edit: Almost forgot, I took a photo of a GU10 LED that I didn't buy but was "flicker-free", too:

KM

Those bulbs that I bought, they still hurt. I can't use them a whole evening without pretty severe eye strain. As it is hard to believe that 0.03% of flicker would cause anyone any trouble, maybe the flicker theory has reached a dead end. My incandescents, which flicker at 20-35% are much more comfortable.

KM

In my backyard there are some street lights for everyone to use when it's dark, so people find their garage and car. I found whenever they used the lights, which turn off automatically after 5 minutes, I O eye strain that persist for 1 hour+. The light that was coming into my room was very subtle. However, I made sure to buy light-blocking roller blinds and curtains to minimize the light.

Edit: A long text got destroyed because my phone's battery died. And I typed it on the phone. I'm not typing it again. Short form: suddenly eye strain in a dark room with everything closed, windows behind me, looking at the bright (known-good) phone screen. I look outside and realize someone has turned on the streetlights. A small reflection on the wall and ceiling caused the eyestrain. The lights flicker at 100 Hz. The reflections are very faint plus not remotely visible when you look at a bright screen.
I'm telling you this to raise awareness that even slightest changes could cause eyestrain. FRC, temporal dithering, the LED bulbs I tried, their flicker is extremely low. Yet they cause trouble. I blocked blue light on my bulbs and verified it was truly blocked with a spectrometer. Blue light is not their issue. Only the flicker remains. And even very low percentages of flicker seem to cause eye strain.

JTL

Wrightpt1 Incorrect, it's based on the frequency and not the voltage.

ryans

Doesn't an regular old-fashion lightbulb flicker because of AC current? Yet most people aren't bothered by them here?

KM

ryans Yes, they flicker because the power network in our countries is constantly switching the current direction and no attempt is made in either lamps or bulbs to convert AC into DC.

I have trouble with some incandescents. It is not caused by the bulb per se. Must have to do either with the lamp electrics or how the light reaches the eye. My bathroom light is always good, my living room light hurts a little over time, and the very bad IKEA "Holmö" lamp that I have bought a while ago gives PWM symptoms immediately, even when the light source is out of sight. Couldn't measure any differences yet on oscilloscopes, but it's hard to do precision measurement on ceiling lamps.

jasonpicard

ryans should only glow 60 times a minute. Or 50 if you use Pal. I heard the biggest problem people were having with these is really cheaply made rough service bulbs. I know two people this was causing eye strain to.

KM

jasonpicard Actually 100/120 times per second

jasonpicard

KM I never knew that. No incandescent has ever bothered my eyes. I don't know how I did function otherwise.

ryans

KM I think this raises a very interesting question. Why is 100x a second flicker in a light bulb fine, but, 220 Hz OLED flicker is not?

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