I film all the LED bulbs I buy in slow motion at 240 fps with an Android phone, and play the movie back on a PC with mplayer using the dot(".") key to move frame by frame. Here is a shot I made comparing 2 brands of LED bulbs: https://youtu.be/QbenId_F2RQ (Edit: yeah you don't have to transfer to a PC, just playing back in slow motion on the phone will still show the effect quite well.)
It's amazing how I find this way that most (but not all!) of LED bulbs flicker with a strobe effect at 120 Hz (frames alternate between bright and dim) because they have crappy power supply designs that fail to smooth the A/C voltage. As a result they flash one time during the positive phase and one time during the negative phase of the 60 Hz A/C mains frequency.
I find this unacceptable. Although not too noticeable in normal conditions, a 120 Hz strobing light is definitely noticeable when your eyes move or track an object illuminated by the bulb.
In my experience, Philips lightbulbs are one of the few brands that don't have this flaw because they take care of converting AC to a stable DC voltage internally. In fact they are advertised as such: https://www.amazon.com/dp/B07CFRCGKC "COMFORTABLE LIGHT: Our products meet strict test criteria including flicker, strobe, glare and color rendition to ensure they meet EyeComfort requirements"
The rotating / reciprocating mass may appear stationary at some RPM.
Just a reminder to only ever use incandescent or halogen lights around machinery you can touch while in operation: drills, lathes, mills, slotting machines, etc.
Before you start a tool you should act out your planned motion. Then start the tool and only perform this motion. If something changes and you cannot complete the motion, stop the tool immediately. Following this and a few other safety tips I've operated power tools for years without incident and I'm legally blind.
Okay, but, say you've configured the tool wrong and now it's destroying your work. You stop the tool. How soon is it safe to grab your work away from the work surface—i.e. when will it go from "it's too dangerous, let it keep destroying the work" to "it's now slow enough to pull the work off of the tool while it's still—slowly—running, to save the work from further damage"? That's a thing you have to figure out with your eyes (and ears).
So, evidently, I may have over stated my initial claim about only using incandescent lights.
Still, it’s something to me conscious of.
Not saying it can't happen but it does seem stupidly hard to achieve.
Many AC motors are synchronized to the frequency of the power line, by the same principal that turbines in the power grid are. So 60hz AC often means 30hz = 1800 rpm motor, and 59.8hz AC means 29.9hz motor. So if you have LEDs with a half bridge rectifier and your machinery is 180 degree rotationally symmetric, it will appear to not be moving, even if the line frequency fluctuates.
Fluorescent tubes are most noticeable, LEDs a little less. Tungsten or Halogen are the only sensible option for workpiece illumination.
For my hobby stuff, I just bought a couple of spare halogens that should see me out.
If the light is flickering it's absolutely guaranteed that it's derived from this.
But it's hard to imagine a lightbulb that emits a short enough pulse of light to make something look stopped. Even an absolute garbage one-way rectifier will be emitting light more than a quarter of the time. That can make a tool look odd, but it won't make it look still.
Not necessarily. If it's a 50/60 or 100/120 Hz flicker then yes, but LED lights with a cheap switching power supply might still flicker at the switching frequency, which could be say 400Hz or something.
Even after 20 years in the metal fabrication industry that scenario still spooks me.
Most will flicker at a multiply of the power line frequency (60 or 50 Hz depending where you live).
It's so common, that most digital cameras have a setting to set the power line frequency, so they can reduce the flickering in the footage.
Incidentally - many alternating current engines are also working with multiples of the powerline frequency, because it's easier that way.
Edited to add: Have you ever heard of a timing light for an engine? This works exactly the way you are describing.
The timing light is then pointed at the flywheel on an engine, which has numbers or marks stamped into it. Each time the spark plug fires the timing light (which is hooked into that same current via induction) lights up for a brief amount of time to show at what timing offset the engine is currently at. (this all happens at hundreds of rpms a minute).
so I'm not sure it's the same
Never underestimate the ability of machinery to rapidly render you dead.
Never underestimate the ability of otherwise intelligent people to intentionally disable safeguards, or guninely make mistakes.
So far, the discussion sounds like it's a theoretical possibility. If it's a real possibility, then it's something that should have happened a number of times.
The rotation frequency would have to be close to a relatively simple multiple (or fraction) of AC frequency but the way electric motors are contstructed if the piece is directly connected to a motor it is very likely it is true.
Visible light impulses influence brain wave patterns (e.g. ), and it might not be beneficial to look at pulsed light with a frequency that is not well researched.
Same thing with screens, most LEDs are dimmed with pulse width modulation , so they flicker at most brightness levels except the very brightest one. Some iPhone X users claim they get a headache when looking at the phone at the lowest brightness setting (OLED is even worse in that regard than LED, IIRC).
On iOS there’s a setting buried deeply in accessibility settings, I think it’s called white point correction.
And on iPhone XS this is even worst. I wonder if there are any solution to PWM problem.
The worst bulbs I've personally seen for flicker were dimmable ones.
The non-dimmable variant from the same range had no noticable flicker.
Price paid also seems to be no indicator of quality – I've had premium LED bulbs from major makes, bought from a reputable wholesaler, that have died after 6 months within days of each other.
I've had cheap no-name imports that have lasted years and had no flicker.
However, there are also LEDs that support legacy dimming, but again translate less current into different flicker patterns...
In other places I don't have dimmers but have low-voltage (12V) cans. Lots of flicker issues there too, presumably due to the 120->12V transformer at the can.
And then I have a light fixture that's both dimmed and a custom 12V setup. I've given up on finding a working dimmer/LED bulb (MR16 GU5.3) there. Probably need new 12V transformers?
Especially when my dog bounces around it looks like she is in a strobe light. I did a couple of videos of it just to "prove" it in some fashion.
¹ — https://news.ycombinator.com/item?id=18644590
This is slightly worrying.
The stroboscopic effect is really fun right until you're in a place with lots of moving parts at a multiple of the strobe frequency.
OTOH it's also used to fine-tune engine timing and such: set a stroboscope at a fraction of the frequency you want, the engine is properly tuned when everything looks completely stopped. Makes it very easy to notice mistiming.
I do some occasional wood-turning, but usually augmented with ambient daylight - along with the dubious safety advantage of having a very noisy electric motor.
Plus I'm old enough to have used a timing light hanging off a distributor on my first car. Try explaining that to the kids of today. ; )
The flicker is a thing from the past (or should be).
The CRT was a 17” running at 60hz. The rubber band sailed past in the span of about 2 screen refreshes, so it traveled that distance in 2/60 of a second. Distance was easy to calculate by the Pythagorean theorem or by holding a ruler to the screen, I forget which.
I saw a test in a Swedish newspaper lately that showed IKEA's cheapest lightbulbs as one of the less flickery ones in the test. IKEA art.nr 303.887.64. So much for the price to guide you.
LED lights are alright. Lots of people think that everything used to be better but my memory is too good to fall for that trap.
Here are two good sites that posted graphs of light intensity over time for a bunch of different bulbs:
Unfortunately, they both stopped updating around 2015. Anyone know of similar sources for more recent bulbs?
> “I am on a mission to make lighting healthy. That's why I made Bedtime Bulb: https://bedtimebulb.com/ It has the lowest flicker I've ever seen in a bulb form factor—even less than those claiming to be "flicker-free."”
In addition to that, a few other database sites that test for flicker were mentioned here³.
² — https://news.ycombinator.com/item?id=18650624
³ — https://news.ycombinator.com/item?id=18646409
I don't have a database, but I can say that most (but not all) filament designs are terrible for flicker--ours is an exception. Philips products seem to have gotten worse in quality over time, probably to remain competitive, but they are better than the worst. Ikea's stuff is pretty good overall. I don't have a consistent recommendation for low-flicker general lighting right now, as every brand has good and bad products.
And, yeah, I tried that Soraa healthy bulb, and it was shockingly bad, given how it was advertised. Even the regular Soraa bulbs were disappointingly flickery, though less so. Also, just looking at the pattern it makes on my phone's rolling shutter, the wave is quite saw-toothed, and I wonder if that makes it worse? I have some Ikea candelabra bulbs which were always pleasant, and I was surprised to see they also left quite a visible flicker pattern on my phone, though much more sinusoidal/smoother.
It's a shame about the flicker in the Soraa bulbs, since the colors really did seem nice.
What's interesting is that the bulb seems to have a nice build quality (from the outside, I didn't open it) and is quite heavy. I suspect they are putting a BIG heatsink in there, as violet pump phosphors tend to degrade quickly.
The other thing that irks me about this product is the "zero blue" messaging. Yes, I can confirm the spectrum looks like what they are advertising, with a peak around 415nm, almost nothing between 440-490nm, and then all the rest of the colors from green to red.
But, green light is just as bad as blue for sleep! The ipRGCs are sensitive to both blue and green (up to around 600nm) This bulb has a lot of green, more than a lot of other light sources. It also has a very unpleasant greenish color (IMO) and low-ish CRI, around 78 on the bulb I tested.
Is it better than a normal 600lm bulb for sleep? Yes. Is it novel? Yes. Is it good in practice? I don't think so.
what does that mean? Duty cycle is 50%, frequency at something Hz? Not being snarky - curious whether there is some kind of standard that your tool compares against.
A duty cycle 50% (or any percent really) isn't bad in itself, it's the frequency that is the culprit. Too low PWM freq and you'll notice it.
Two factors are often used to describe flicker for lighting:
- Modulation %, a.k.a. % Flicker [The height or modulation of the waveform, formula is 100% * (A - B) / (A + B)]
- Frequency [self-explanatory]
Flicker Index is also used (refer to  page 7 for more info) but rarely.
Duty cycle is not considered relevant, as you mentioned.
Some tools designed to measure lighting, such as my UPRtek CV600 , spit out % flicker, frequency, and flicker index, in addition to a bunch of spectrophotometry metrics. It's also pretty easy to calculate the modulation % with an oscilloscope and photodiode, it's just Vp-p / Vmax.
IEEE 1789  roughly says that the higher the flicker frequency, the more acceptable it is to have a high modulation %. If you look at the graphic on  page 18, you can see this relationship. The white area is considered unsafe, the yellow area is "low-risk", and the green area is "safe." I don't 100% agree with this personally, as most incandescent lighting, with around 6-11% flicker at 100-120 Hz, would fall into the unsafe or low-risk category. But the Soraa product is definitely in the unsafe category.
For reference, I plotted my product (Bedtime Bulb) against an incandescent A19, Lighting Science's Goodnight A19, and Soraa's Healthy A19 on an IEEE 1789 graphic  with a Python tool I'm developing, Beautiful Flicker . You can see that this incandescent, measured around 10%, is on the border between unsafe and low-risk by this standard.
Hope this helps!
 IEEE 1789: A new standard for evaluating flickering LEDs?: https://www.dial.de/en/blog/article/ieee-1789-a-new-standard...
 Flicker: Understanding the New Recommended Practice (PDF) https://www.energy.gov/sites/prod/files/2015/05/f22/miller%2...
 UPRtek CV600 https://www.uprtek.com/en/product/SPECTRAL-COLOR-METER/CV600...
 IEEE 1789 Graphic Comparing 4 Light Sources https://github.com/yeutterg/beautiful-flicker/blob/master/ou...
 Beautiful Flicker https://github.com/yeutterg/beautiful-flicker
The switch-mode power supplies in proper lamps get the stuff done way better and there will be no noticeable flicker. Maybe in the order of several kHz in ripple which you cannot see.
Also; cheap off brands (looking at you china) sometimes have caps rated at 250V which is far from the peak mains rate of about 320V (in 220/230V countries).
* at least in the UK
I mean, it looks absolutely fine as long as the light source and viewer are both static - just a shame vehicles tend to be moving :(
Source: I just had a problem with a malfunctioning light switch (not even a dimming switch, a plain two-state switch) wherein sometimes it would poorly complete the circuit, and one bulb out of the four on the circuit would start oscillating on and off. (If you removed the one bulb, another would start. If you plugged the first bulb back in, in the original slot or another, it would happen to the first bulb only.)
Of course it's still hit or miss, compatibility between bulbs and dimmers seems to be very hard to judge without testing these days.
Most dimmers work via pulse width modulation , i.e. the power supply is switched on/off in a different interval (more off time means lower brightness). A true flicker-free dimmed LED has to be dimmed in an analog way (probably only feasible for "dumb" light bulbs). PWM of 20kHz or something might also work, but who knows what that does to brain waves.
Through trial and error I found that 72hz was acceptable/ok and 90hz and above was great. Other folks generally didn't notice, but sometimes could if I showed them to look sideways etc. This must explain why I've never knowingly been bothered by 120hz LED flicker, it is below my ability to consciously notice.
Curious, I took a look at several bulbs, with the mobile at 240fps trick described elsewhere. A new Feit dimmable, new Ecosmart non, a several year old Ikea, and a no-name CFL. All showed flicker except the CFL. All the LEDs flickered, but the amplitude was larger on the ecosmart. Feit and Ikea had a small amplitude.
Perhaps they are putting half the LEDs out of phase to get the smaller amplitude, or they should?
Of course it's not the LEDs that do this but the cheap AC-DC conversion bridge rectifier.
Do I need to buy a specific model of Philips bulbs? Or is my Ikea lamp the culprit now? I paid a ton of money for a certified flicker free monitor so I'm very keen on making sure the lamps are flicker free as well.
Lights is something that I used to cheap out on but no more. Not buying Philips bulbs is definitely 'penny wise, pound foolish'.
Also, Philips Hue!
Alas this isn't a problem. If a lightbulb goes, Amazon send me a new one out now free of charge and tell me to throw the old one in the trash.
This is one manufacturer, prevalent on Amazon, the Long Life Lamp Company. Long Life my ass.
They have been replaced by Philips and Ikea LED bulbs now which the oldest are 5 years old now and still going strong.
Edit: one thing to note is the really cheap ones run pretty hot. They have 105 oC rated capacitors in them. If you look at the derating curves at the running temperature they are clearly designed to last just past a year.
The Walmart bulbs without any special pricing were way cheaper than the Cree bulbs from Home Depot, but even better, there was some sort of automatic rebate or something like that in cooperation with the local electric company that made the Walmart bulbs $0.17. By "automatic rebate", I mean that the bulbs rang up on checkout at $0.17. No rebate forms to send in or anything like that.
Were those the original Cree bulbs with the heavy, finned metal heatsink around the base ?
I currently have a bag of about 14 of those that I bought (with great enthusiasm) and that burned out (or turned weird purple colors) within 2-3 years.
New style cree bulbs appear to have these issues solved. In fact, I continue to buy them as they perform better than other (satco, fein) bulbs that I have. In most cases I get satco/fein as long as they have the color temperature and output I want, but if I am having issues with a dimmer, etc., I get a cree bulb.
Could you tell us that email address ? I have a box of 14 original Cree bulbs that I would like to get replaced...
If I cared more I might try to take the bulbs apart in a way that I could get them back together and just bypass the failed LED with a resister to bring the bulb back to life (at 15% reduced capacity or so).
I have been very disappointed in how hot the bulbs run as well. It feels like they must be wasting a lot of energy to run that hot.
They've run cheap and cold for years now, without a single failure.
I suspect that there's some planned obsolescence in newer products.
These were fairly expensive, about $11 each (the going rate at the time), and were TCP brand, but it was unpleasant to read that newer bulbs might be far worse when it comes time to replace them, even if they are cheaper. I love the fact that they die so infrequently that I don't have to keep any spares around.
I think it gets worse as time goes on, because manufacturers gain experience with the lifespan of their components and learn exactly where they can cut. If you’re not quite sure how long something will last, you’ll probably err on the side of caution and engineer it to last longer than needed in case you got it wrong.
However, as the article notes, people may not be interested in paying a premium for a product that lasts 10y instead of 5y or 20y instead of 10y, since the tech can change or maybe it’s susceptical to other kinds of degradation.
My flat has some sort of bad-quality switches and when switching on/off the lights I often used to have some failures when using classic light bulbs (I have no clue about electricity - in any case in some way when I press the on/off-button the transition seems to be "dirty").
4 months ago I bought a new lamp and decided to give OSRAM-bulbs a go (it's a well known brand in Europe but up until then I always used Philips) => 2 LED-bulbs failed within 2 weeks (I put in the 1st bulb => failed after 2 weeks => replaced it with a 2nd bulb => failed again after 2 weeks).
I then went back to using Philips-bulbs and the one I used to replace the last one which failed is still working now.
Philips seems to be, at least in my case, definitely better or at least more "lenient/tolerant" at least concerning my the switches installed in my flat.
Anybody having negative experiences with Philips or positive ones with OSRAM or the opposite?
It is a problem in the sense that it creates waste and pollution. There is a cost to throwing things out, and for shipping things across the country without limit.
I do agree with you fundamentally however.
the first being, areas with vibration meaning near doors and garage door openers. great locations to eat LED bulbs. this might be related to your heat sink adhesive issue.
the second is the upside down tulip light fixtures common in bathrooms, apparently they cook quite well unless ventilated at the top.
Kind of like how replacing a gas dryer "requires" a licensed plumber to make the gas connection or you're "required" to drive no faster than the speed limit at all times.
You're getting the runaround. If it was in a vacant apartment that they were showing to people it would already be fixed. If they cared about getting it done ASAP they'd either shell out the big bucks or ignore the law.
Edit: I think a lot of people on HN don't realize how simple swapping failed parts is. Swapping a failed water heater or electrical fixture (especially light fixtures) is a waste of the skilled tradesman's time and the customer's money. Even an incompetent landlord or maintenance service should be able to get it done.
It's rarely criminal for homeowners to DIY within building code regulations, permits be damned. When the bank owns part, appraisal or home sales happen, insurance policies are involved non disclosure can be fraud.
My 2¢ on DIY from general contracting experience,
Undetected water leaks can be fucking expensive, consider location and worst case scenario when making decisions. Don't use shit like AS SEEN ON TV toilet tank gaskets or tool free water valves in a production environment.
Thread seal tape is a lubricant that helps seat solid metal (usually) connections to create a seal, not a sealant. (can be welding agent for polymers)
Water, dish soap, spray bottle helps test connections.
Gases have different smells or lack there of, different densities (sink, rise, displace oxygen), can combust in different concentration ranges, etc so understand this.
Changing the load or adding potential for increased load on a circuit (new fixtures, receptacles, breaker, fuse, conductor, etc) could cause arcing and lead to fire in unexpected ways. Sections of copper wire get replaced with smaller gauge at some point over a properties history and then get sealed back up in a wall, among all kinds of other wacky shit. Understand the physics and dangers.
Connections are important, and common points of failure. They should be appropriately terminated and enclosed. Use the proper size wire nuts.
Valves, switches, and people are flaky so plan accordingly. Test shut-off or failsafe mechanisms and have a plan for the worst case scenario.
Edit: I've seen this at least in NY, Florida, California
I've read that you can't move chairs, etc, either. I understand it's part of the contracts between venues and unions.
IIRC, Australia requires an electrician for even this sort of minor work.
That likely depends on local codes; not sure about light fixtures specifically, but I definitely have encountered variations in different cities in the same county when it comes to ceiling fans.
Those laws (especially when combined with licensing requirements that exclude all but those who have a full time career in that field) are a massive hindrance to individuals and many businesses. They usually amount to little more than a potential transfer of liability. If your house burns down maybe you can try to point the finger at the licensed professional (good luck at that). The only thing it accomplishes is making it (slightly) harder for people who are habitually grossly negligent to keep working in that field. This is a non-benefit IMO because so much business is based on reputation anyway. The downside is that by artificially raising the minimum price access to access skilled labor you cause all sorts of work to be forgone because people can't afford it.
Plenty of house fires have been started by people who couldn't afford to pay an electrician but could afford an extension cord.
Edit: Since I'm apparently so wrong does anyone want to explain why. A down-vote without a reply is roughly synonymous with "your opinion is inconvenient to me but I cannot refute it"
...is using the downvote correctly. Downvoting is for comments that are not productive contributions to the kind of discussion desired on HN, responding to any post that merits a downvote is increasing the noise-to-signal ratio.
* Home rennovation (requiring city signoff)
* Home repairs
* Rental repairs
* Court over repairs or alterations to property
In other countries (both in Sweden where I lived before and here in Japan where I live now) there are special ceiling power outlets, so replacing a light fixture is just a question of unplugging and plugging in again. Japan: https://farm5.staticflickr.com/4279/35698610491_8787f45eae.j... https://farm5.staticflickr.com/4230/35790814576_382943d360.j... Sweden: https://www.eldirekt.se/pub_images/medium/1890776__13222.jpg
There's a wide range of quality ceiling light fixtures that you just clip into place, and the LED chips are on a huge metal heatsink so they run very cool https://panasonic.jp/light/led/products.html
With a retrofit lamp, you can use a high quality trim baffle (these things cost about $12, are quite well designed, and are probably already in your house and put a civilized PAR30 or PAR38 LED in, and you get a much better light distribution.
Back when lamps were all standardized incandescents, fixtures could focus on quality. Now, with LEDs, I suspect that manufacturers focus on how cheaply they can build a driver and assembly that meets some minimum performance criteria. So, with retrofit lamps, at least the fixture design is separate.
(There are exceptions, of course. Very high quality dedicated fixtures exist, but they’re quite expensive.)
One thing to pay close attention to on the package is whether the bulb can be run in an enclosed fixture. The package should always specify. Following this guidance and picking the right bulb for the fixture will help ensure you get the service life you expect. I don't think I've found any 100W equivalents that are OK'd for fully enclosed application, and 60W equivalent is like 50/50.
I also own some 5W/400lm ikea bulbs for general room lighting and they do run warm, maybe something like 40°C ± 5°C. The fixture/thingy around the bulb is roughly the size of a fist.
The bulbs are pretty new so I can't say anything about the lifespan of the bulbs, but the price is reasonable, they are not the fancy smart bulbs.
Worse than that, though, it was unusable with a dimmer switch; the whole thing visibly flickered every few seconds. I felt bad returning it because I really wanted it to work out, but the quality just wasn't there.
My other LED fixtures were ordered through aliexpress. The fixtures were fine, but the transformers that came with the fixtures all failed and had to be replaced (overheated, melted the plastic casing). This turned out to be tricky, because the LED drivers available on ebay and aliexpress are never the same, there are constantly new shoddy ones from noname brands, and the ones I had bought before tend to be nowhere to be found when I need a new one.
 Except after a power outage - then they eerily flash on and off like something out of Stranger Things.
The sad thing is that the latter is still cheaper than buying from a 'local' shop.
Edit: looking at the price of fixtures, the economic argument is poor as well.
EDIT: This was not entirely correct as the article says:
> The US Department of Energy (DoE)’s solid-state lighting program supports research and development of LED technologies, and their website contains volumes of data on LED lighting systems. Their Lifetime and Reliability Fact Sheet contains data on the failure rate of 5,400 outdoor lamps over 34 million hours of operation. Interestingly, the LEDs themselves account for only 10% of the failures; driver circuitry, on the other hand, was responsible almost 60% of the time. The remainder of failures were due to housing problems, which may not be as applicable for bulbs in indoor use.
Some don't even have a bridge rectifier - just a couple of capacitors and that's it.
It never answers the question. It has an anecdote about the author's own lamps that ran an estimated 15-20k hours with an advertised lifespan of 30k and have degraded to the point where they will replace them. That's n=1 and nowhere near 100k hours, or even 50k as the author mentions early-adopters will remember seeing advertised.
The article contains a lot of info, but does not actually answer the original questions it poses in the title and the second paragraph.
>It’s possible that the reduced lifetime ratings we see on current bulbs simply reflect better knowledge about actual performance of existing LED technology over time.
I know for a fact that some of the testing houses have done extended on/off cycle testing for some of the big box retailers looking to keep the lamp vendors honest on real lifetime performance of A19 class bulbs. I've been in such a test chamber.
 - https://www.wired.com/story/ikea-fyrtur-smart-blinds/
- when used with a dimmer
- when a large load is applied to the same circuit
Most other bulbs fail one of those, but I haven't had an ikea branded bulb do poor in any condition.
Supposedly that's better for night vision, light pollution and various animals. But everywhere I go I see yellowish sodium vapor lights replaced with white LEDs.
The lumens out of a legacy high pressure sodium lamp are very high. It is still an engineering challenge to get comparable lumens out of LEDs at price point the market will bear.
Our eyes are most sensitive in the green, but green LEDs are not necessarily the most sensitive
A high efficiency LED assembly is still producing on the order of 50% light and 50% heat.
1) Better cooling: non-tooth paste thermal compound, more space for heatsinks
2) Not overdriven LEDs
3) Introduce DC power lines (within the house/building) - galvanic corrosion still might be an issue
4) In lack of point 3 - more efficient AC -> DC converters, preferably with lower temp threshold,
having 150C default for the internal mosfet on 8pin LED driver is really high.
4a) AC-DCs require quality passive components: coil and caps.
I've tried through 5 different MR type LED bulbs and every one of them had an extreme flickering issue. All of them were labeled as dimmable.
I've had better luck with the standard A type bulbs. But only because there were more thorough reviews available.
If dimming is important to you, there are a number of architectural grade bulbs that offer deep dimming to 5% or 1%.
Personally, for this application, I've had good luck with Cree bulbs of this type at home (on Leviton dimmers). And in the house of worship environment with Cree bulbs on Doug Fleenor dimmers (http://www.dfd.com/dmx8dim.html)
I'd also like to add that looking for lamps with the CEC Title 20 & Title 24 certifications should be helpful in finding bulbs that dim well, as California has much stricter regulations on dimming flicker and buzz than the rest of the country.
But, in practice, other components generally fail before the LEDs have a (binary) failure.
The cheaper bulb in the original article has linear current control. Inside the ASIC, this could be as simple as a BJT or FET in saturation with a (somewhat) controlled base/gate voltage, maybe with some temperature compensation.
The linearly regulated bulb will have less RF emissions, though you could theoretically still have a bit of rf trash from edge effects depending on the rectifier and filter cap.
Any bulb that has passed FCC Class B will have an upper bound on conducted and radiated emissions, but you can pass such tests on a wide range of margins, and therefore certification isn't useful to clarify which bulbs have the lowest emissions.