I can't really live well with Flickering LED Lights, even if we are talking about 2 to 3khz dimming frequency. Which LED Lights did you test out that actually have frequencyies above 25khz, and dont give you bad sympthoms?

I would love to hear from others as well! I’m in the United States and I’m looking, but can’t find any major lighting manufacturer that is currently making flicker-free LED bulbs. Philips and Sunco claim that their bulbs are "flicker-free" in their marketing, but when you take a closer look at the notes (Philips) or talk to a sales rep (Sunco), they acknowledge that they’re only talking about *visible* flicker. Their bulbs are not free of *invisible* 120Hz flicker. I’ve been learning more about bulb wiring lately, and it turns out that the manufacturer needs to choose to put an extra circuit into the bulb (a DC-DC converter) to eliminate the 120 Hz flicker created by the AC mains. The cost of adding this is low (about 10 euro cents, according to a [report](https://www.eceee.org/static/media/uploads/site-2/news/swecovernotesvm_study_181212.pdf) by the Swedish Energy Agency). However, including the circuitry to make a bulb have zero flicker reduces its energy efficiency somewhat - these bulbs have somewhat low power factors. A power factor less than 1 means that some of the energy drawn into the bulb circuitry is lost as heat instead of being used directly to produce light. To qualify for the US Energy Star certification and to be sold in California, bulbs need to have a power factor >= 0.7. My favorite Philips A19 dimmable LED bulbs from 2013 that are completely flicker-free only have a power factor of 0.65 according to [LEDbenchmark](http://www.ledbenchmark.com/display.php?id=173&name=Philips+11W+Dimmable+AmbientLED+Soft+White). The only flicker-free bulbs I’ve been able to find on sale in the US today are A19 bulbs from [Waveform Lighting](https://store.waveformlighting.com/collections/a19-bulbs), but their power factor is 0.6 so they can’t be sold in California. [**EDIT**: as of June 2021, the Waveform bulbs have been updated so their power factor is >0.7 and they can now be shipped to California (Title 20 compliant); I just bought more to put in a family member’s home]. I’m pretty sure that all of their non-filament (normal bulb-style) A19s are flicker-free even if the website labeling is missing. They actually publish the flicker percent and flicker index too! As of a week ago, I own their 2700K Centric Home A19 and 2 of their art-specific bulbs (D50 and D65 A19s). All of these bulbs are actually flicker-free. They have no flicker on a slow-motion video and they’re not causing pain or migraine. Their reviews are from a lot of grateful migraine patients. During a flicker migraine, I find flicker-free LEDs to be even better for me than some incandescents. Waveform also sells drivers for strip lighting/industrial lighting that they advertise as "flicker-free" and that have PWM at 30KHz. I haven’t tried them yet, but am looking at them to maybe use in the classroom. The lighting industry seems to be abandoning the 2015 [IEEE 1789 report recommendations ](http://www.bio-licht.org/02_resources/info_ieee_2015_standards-1789.pdf)for flicker which were a guess about appropriate limits for invisible flicker based on old studies of the biological effects of fluorescent lights - these standards aren’t strong enough to prevent my migraines from LED flicker. Now the lighting industry is adopting less stringent "SVM" standards and a "Pst" standard that only applies to visible flicker. Bulbs I’ve tested recently that are NOT flicker-free according to both slow-motion phone video (all have 120 Hz flicker) and according to my flicker-sensitive migraine brain: Philips "eye-comfort" "flicker-free" PAR20 (model 9290013169). Philips "eye-comfort" "warm glow" 60W-equivalent 8.8W A19 (model 9290019409B). Sunco PAR20 bulbs with "flicker-free technology" (model L9-PAR20DWP-7W). GE 60W-equivalent dimmable 10W A19 (model 67615). Target Up&Up (store brand) 60W-equivalent non-dimmable 10W A19 (model A800830). I’m beginning to think that the major US manufacturers may have abandoned making flicker-free bulbs due to the lower power factor and due to the absence of evidence in the medical literature for the biological effects of LED flicker. I’m curious about a few things: 1. If you live in a country with 50 Hz AC power (so 100Hz flicker from AC), do the LED bulbs sold in your country today flicker at 100 Hz if you take a slow-motion video of them with your phone camera? I’m curious because 100 Hz is around the limit of being visible flicker for some people, so I’m wondering if it’s just the US that’s getting by with making all flickering bulbs since our 120 Hz flicker shouldn’t be visible. 2. Has anyone in the US found any other flicker-free bulbs on the market today that you’ve actually tested in some way? So far, I only know of [Waveform](https://www.waveformlighting.com/), but their product line isn’t comprehensive. 3. Does anyone know of any flicker-free drivers for industrial-style LEDs being sold in the US? 4. I seem to have more migraine trouble from flickering industrial-style LED strip lighting than from the average flickering household bulb even though the strip lighting flickers much faster. Does anyone else have a similar (or different) experience? 5. Other than calling companies or leaving bad reviews, has anyone found any effective action to take against bulb flicker? I’ve tried a few different mostly ineffective things - so far filing a report about bulbs causing the "injury" of migraine with the US [Consumer Product Safety Commission](https://www.cpsc.gov/) has resulted in the best company response - it has resulted in an internal investigation that has included their engineers. I’m not sure whether they’re really doing anything other than verifying the bulb is within their specs for visible flicker, but if companies start to hear about problems through this avenue, it could also create a paper trail for further advocacy. I’m also trying to push the medical community to study this so there will be evidence for policy-makers, but that’s another story. By the way, if you’re curious, this is how I use my iPhone camera to estimate flicker rate: In the settings, it tells me that the Slo-Mo video rate is 240 frames per second. If your phone has options, set it to the highest frames per second. In the absence of other ambient light, focus on the bulb so the shutter speed is fast - that makes it easier to detect subtle flicker, but it actually doesn’t matter if the flicker is bad. Record the slo-mo video for a few seconds. Upon play-back, you will see obvious flashing from 120Hz flicker. Faster flicker will result in bands of bright/dark moving from one side of the screen to the other. This happens because when taking a single frame of the video, the phone records the image starting on one long edge of the frame and moving toward the other long edge. This means that 120Hz flicker on a 240fps video, when viewed frame-by-frame, looks darker on one side of the frame and brighter on the other side of the frame. The dark and bright regions are on the opposite sides in the next frame. Each frame represents one half of the full cycle so (0.5 cycles/frame) x (240 frames/second) = 120 cycles/second = 120 Hz. With faster flicker, there can be multiple bright/dark phases per frame. On the iPhone, the bands will always be parallel to the long edge of the phone because of the side-to-side way that the phone takes individual image frames in the video. When there are many bands, just count how many dark bands you see per frame since that will tell you the number of cycles per frame. Then multiply as before. For example, if there are 12 dark bands in one frame, (12 cycles/frame) x (240 frames/second) = 2880 cycles/second = 2880 Hz. Obviously, this is just a rough estimate, but it’s not too bad. It’s easiest to see this kind of banding in the part of the image where the lamp is. So if you suspect rapid flicker, getting your phone closer to the lamp so that the lamp fills most of the frame (at least spanning the short direction across the phone) can be helpful to give you a larger area in which to detect banding. Banding can be subtle or obvious, depending on how much the light dims in the dark phase. Flicker-free LED bulbs will not have any flashing or banding in the slow motion video. The light should look so steady that you'll double-check to see if you’re actually playing the video. I get migraines from industrial LED strip lights with very subtle banding in the video in a pattern suggesting about 1500 Hz flicker. I also get migraines from every household LED bulb with 120 Hz flicker that I’ve ever encountered. I’ve never had a problem with household LEDs that have a 0.00 flicker index. I’ve never had a problem with LEDs that use constant DC power.

@"jen"#p16368 Nice post! Do you reccomend the waveform light bulbs or better to try the led strips with the dimmable option? Yeah unfortunately the bulbs are only 800lm

@"lillo9546"#p16370 I think whether you try bulbs or strip lighting partly depends on your application/illumination needs. I’ve only personally tried the Waveform household A19 bulbs so far. They’re comparable in brightness to other typical 60W-equivalent bulbs, so are the brightness I was looking for at home. I’ve recently spoken with one of their representatives about their options for strip lighting and other industrial options that might be used for lab/classroom lighting at work, and I'm hopeful that 30kHz flicker would be fast enough not to bother me, but I haven’t actually tried it yet. The wiring necessary to set up the industrial-style lighting is beyond my skill set too. Whether we can try it is going to be decided by others at my workplace. I hope you can find an option that works for you!

@"jen"#p16371 I would totally love to buy thoose LED Bulbs from Waveform, but I am from Italy and shipping cost are soo high, then I have to keep in mind for extra expensive duty fees. Do you guys know where I could buy this kind of lamp in Italy or with interational free shipping?

I don't think any bulb can completely eliminate the AC flicker. They do only reduce it so far, at least that's what I have seen when measuring promising bulbs. Even those advertised as "flicker-free" had measurable flicker (100/120 Hz). It can be very small, so methods like slow-mo camera won't capture it. But the brain probably can.

@"KM"#p16411 waveform lightning flickers at 47khz

@"lillo9546"#p16412 that does not mean they don't have 100/120 Hz flicker. Both frequencies can both be there simultaneously, and most probably will be. Try the photodiode setup in the oscilloscope thread if you want to check it. But you'll need a good oscilloscope that has native AC mode. That aside, I don't call anything that flickers "flicker-free". If there is a frequency, no matter how fast, the product does flicker, period. Companies selling "flicker-free" bulbs that flicker must be joking.

@"KM"#p16413 I agree with you that almost all companies that advertise “flicker-free" are joking since their bulbs have very obvious 120 Hz flicker detectable by slow-motion cell phone video. However if they choose to engineer the bulbs differently, companies _can_ make LED bulbs that are essentially flicker-free and much better than incandescents. I believe we should be asking companies to make this kind of bulb. Check out the flicker graph for these old LED [bulbs](http://www.ledbenchmark.com/display.php?id=173&name=Philips+11W+Dimmable+AmbientLED+Soft+White) - it’s pretty much flat and the flicker frequency is over 17000 Hz. I own these bulbs and love them. Never a twinge of irritation. They’re easier on my head than even some of my incandescents. This is the kind of bulb I think we should be hoping returns to the marketplace so people have the choice of installing something that’s essentially flicker-free. I don’t have the proper equipment to test the flicker metrics of my new Waveform bulbs myself, but by cell phone slow-motion video I can’t detect even a hint of flicker and neither can my head. I think the flicker statistics they provide on their website (less than 1% flicker, 0.00 flicker index) are genuine - these bulbs really do seem to have been engineered to be essentially flicker-free. Unfortunately, where I live, it’s hard to walk down the street anymore without being assaulted by invisible LED flicker. If we don’t want sensitive individuals like me to be in a constant state of migraine, I think we really need to encourage flicker-free LED manufacture. Only having homes with low-flicker incandescents may not be sufficient protection if there's too much invisible LED flicker in the environment. I know I can’t manage to avoid the flickering LEDs owned by others anymore. Unfortunately there are so few actually flicker-free LEDs being sold right now that people don’t have much of a choice. And the “flicker-free" marketing lies today from most companies make it seem like engineering that eliminates the 120Hz ripple and is actually flicker-free is a myth, when instead it is definitely something that used to be done in many LED bulbs several years ago.

Just adding onto this excellent thread. I'd fallen for Philips' marketing and bought their "flicker free" bulbs to relieve my headaches. Since I'm still having headaches, I did some digging and found two documents, which might be the ones @"jen"#238 found as well. 1. Philips bulbs are manufactured by a company called Signify as referenced [here](https://images.philips.com/is/content/PhilipsConsumer/PDFDownloads/United%20States/ODLI20180808-001-PDF-en_US-EyeComfort-whitepaper-English-master-v2.pdf) 2. Signify has a document ([here](https://signify-portal-oem-nam-prod.trimm.net/dam/jcr:24d1c6e4-7a8b-4cb9-b7b6-733b7047b11e/Flicker%20measurement%20NEMA77%20and%20IEEE1789%20White%20Paper.pdf)) that, if I'm reading it correctly, attempts to discredit the IEEE1789 flicker standard That second document was enough to confirm for me that Philips/Signify bulbs aren't really flicker-free at all. (Why try to get around a published standard if you're compliant?) Per this thread, I bought a 6-pack of Waveform bulbs last weekend. Excited for them to arrive. Will report back on how they work out.

@"cranthon"#p19455 To be fair, it seems the document is more about "temporal light artifacts", i.e. consciously perceiving flicker and stroboscopic effects.

Flicker Free LED Lightning it's the most important thing! Which one to buy?

Quad43

charles8 Thanks Charles. Are these the green packs or the purple?

GregAtkinson

GregAtkinson I'm going to buy some from 2-3 different sellers on eBay; presumably their stock is older. I'll keep you posted on that.

There are a few old, non-flickering ones on eBay. Here’s an eBay listing that has them for about $2 per bulb with shipping.
https://www.ebay.com/itm/155900291630

Here's a couple pictures showing the differences. the newer (bad) box is smaller; the older (good) box is larger.

I bought about 150 bulbs from various sellers that will hopefully last until my kids put me in a nursing home. It’s a large box, but still a very poignant reminder of my limited time on earth.

simplex

GregAtkinson Here is the "CENTRIC HOME™ Flicker-Free A21 15W LED Bulb." This is on DC mode.

Finaly, all when we get not thin line wave-style, it mean it has extremly high-freq modulation which you can see limiting threshold window? Not in ms, but in ns?

Storme

Many commercially available LED lights can still cause discomfort even at frequencies of 2-3kHz. Higher frequencies, such as 25kHz and above, can significantly reduce flicker-related issues. Some of Tridonic's LED drivers support high frequency PWM dimming, which can reach 30kHz or higher. ShineLong's high-end LED products, such as the Alpha series or the Rancher series, support strobo-free drivers and often prefer high-frequency dimming designs.

simplex

Storme can significantly

They key word is … can

Not sure, high freq PWM (30khz) lamps better, than low freq (100hz sine wave)

« Previous Page