25 ms·

Teardown of a $1.25 LED Lightbulb

324 points by teucris 7y ago

WrtCdEvrydy 7y ago
I love seeing designs that fail while keeping the product as electrically hot as possible - said noone ever.
- ygra 7y ago
  Oh, Big Clive might say something to that effect, I'm sure.
baybal2 7y ago
> A fused neutral design would leave all of the bulb electronics hot. Strange. Depends on what country you are living in. It's not new for me to see a product passing safety certification in one country, failing in another, but still ending up in it because of messup by people running the OEM industry. Second to it, in a normal country, for an electrical appliance, failing short, and triggering a short circuit protection is a relatively safe alternative to having a dedicated fail safe circuit, but in countries with building codes not saying anything about wiring safety, it often means a fire.
- cotillion 7y ago
  Considering how popular unpolarized plugs are all over the world I don't think a fused neutral is much of a problem in a lamp.
- tinus_hn 7y ago
  Anyway European Schuko plugs are not even polarized, there is no way to know which wire is hot.
  - gwbas1c 7y ago
    Honestly, I think it's better that we view polarization as a historical oddity. So many people don't understand the concept. Even I have trouble understanding the real difference between ground and neutral, because neutral connects to ground in the breaker panel. I'm not even sure if neutral goes through the breaker?
    - ars 7y ago
      Neutral exists separately from ground only because if there is some residual resistance in the line, there will be voltage on the neutral. So you have a separate ground that normally sees no voltage at all. You are correct, the neutral does not go through the breaker. It is usually wired inside the breaker panel though. Some localities want the neutral and ground wired separately (to separate bus bars), with a single point connecting them, but most don't care and the neutral and ground are attached to the exact same place inside the breaker panel. Electrically, the neutral and ground are at the same potential, assuming magic wires with zero resistance, but in the real world the wire does have resistance, especially if it was poorly installed, so they are not always at the same potential. There could also be capacitance in the line.
    - rootusrootus 7y ago
      The neutral handles the expected load, while the ground is designed specifically to be an alternate current path from the case (assuming it is conductive) that has low resistance and will immediately flow enough current to trip the breaker in case the hot somehow comes into contact with the case. Neutral does not go through the breaker, correct.
    - zAy0LfpBZLC8mAC 7y ago
      The purpose of separate wires is twofold: 1. It's to provide protection in case of neutral failure. If you have an appliance with the case grounded via neutral and the neutral wiring fails, you now have the case connected to live (through any appliance that is switched on). With separate ground, nothing happens as you are only allowed to connect ground to neutral at a point where failure of the upstream wiring is practically impossible (i.e., wires so thick that they practically won't break). 2. It's to provide a path for ground fault currents that does not pass through the RCD, if you have an RCD. While neutral doesn't go through the circuit breaker, it does go through the RCD, so as to measure the difference in current between live and neutral. If your appliance is grounded vial neutral, any ground fault (connection from live to the case) looks like regular load current to the RCD, if it is grounded via separate ground, the fault current bypasses the RCD and thus causes it to trigger, even for a small current that would not trigger over current protection.
spookthesunset 7y ago
Some of these cheap LED bulbs have horrible flicker. For a fun time, record a slow motion video of a cheap bulb on your phone and play it back. Like half the damn video is black (pretty sure it is because they literally chop out half the AC sine wave with a diode). LED Christmas lights are also really bad. Then compare it to something like a Phillips hue bulb. The difference between the two is pretty big. On a side note I sometimes wonder if other animals have a quicker “refresh rate” on their eyes and see nothing but very visible flicker on these bad LED bulbs. I also wonder if some animals could see the raster scan in action on old CRTs...
- all_usernames 7y ago
  Dogs apparently have a visual sample rate of around 75Hz, meaning they wouldn't see much in an old analog TV, but newer HDTVs might look realistic to them. https://thebark.com/content/heres-what-dogs-see-when-they-watch-television https://thebark.com/content/heres-what-dogs-see-when-they-wa...
  - berdon 7y ago
    Our two dogs watch our 4k TV often. And bark at various things, actors, subjects they don't like.
    - Topgamer7 7y ago
      Had a dog that would press her nose right up to an ipad screen and move her face around to follow the squirrel, bird, or dog that interested her. She would get very excited about it. She also watched TV. At one point sitting on hind legs trying to elevate off the bed to be inline with the center of the image.
    - bradstewart 7y ago
      Only one of my dogs appears to recognize things in the TV. She'll bark at something on screen, and my other dog will run to a window or door trying to figure what he missed. Always wondered why...
  - 7y ago
petercooper 7y ago
If, for some reason, lighting teardowns are a fascination of yours, I thought I should mention "bigclive", a YouTube channel devoted to this very topic :-D https://www.youtube.com/user/bigclivedotcom/videos https://www.youtube.com/user/bigclivedotcom/videos (the author of this blog post also has a channel at https://www.youtube.com/user/electronupdate/videos https://www.youtube.com/user/electronupdate/videos )
- jcims 7y ago
  Indeed! Also https://www.youtube.com/user/mikeselectricstuff/videos https://www.youtube.com/user/mikeselectricstuff/videos for lighting and scrap medical/industrial equipment teardowns. If you are into RF dark magic, https://www.youtube.com/user/TheSignalPathBlog/videos https://www.youtube.com/user/TheSignalPathBlog/videos for teardowns (and repairs!) of GHz scopes, network analyzers, etc.
- ASalazarMX 7y ago
  Never expected to see cheese and electronic teardowns mixed.
  - teh_klev 7y ago
    That whole stuffing 240v into a BabyBel cheese and Co-op mincemeat pies thing was quite amusing, I guess the festive season can be "slow news" days even for video bloggers. That said, back in the early 90's when I was a field engineer, a mate and myself used apply 240v to foodstuffs in the company workshop "just to see what happened" when things were a bit slow. The resulting smells were somewhat odd.
    - petercooper 7y ago
      Have you ever seen "PhotonicInduction"? He did a lot of very dangerous and borderline insane stuff with electricity like running up a 20KW bulb in his house: https://www.youtube.com/watch?v=LT5_-A0m8_U https://www.youtube.com/watch?v=LT5_-A0m8_U (or, more famously, chucking a cinder block into a washing machine)
burgerquizz 7y ago
Hijacking the comments. I have a project that would involve about 15+ smart Lightbulbs. Anyone would know any decent/cheaper alternative to the Phillips Hue bulbs?
- mlonkibjuyhv 7y ago
  Check Ikea
- ChuckNorris89 7y ago
  Xiaomi Yeelight
- vassie 7y ago
  These videos compare a few on offer... https://www.youtube.com/watch?v=osauwVoP4a8 https://www.youtube.com/watch?v=osauwVoP4a8 https://www.youtube.com/watch?v=-ZPo7C3PDT4 https://www.youtube.com/watch?v=-ZPo7C3PDT4 I also highly recommend the Smart Home Solver YouTube channel if you're interested in home automation https://www.youtube.com/channel/UCwOBG77Tm8cE24FPxHb_abw https://www.youtube.com/channel/UCwOBG77Tm8cE24FPxHb_abw
- Klathmon 7y ago
  Think outside the box (outside the bulb?) z-wave "behind the switch" modules are super easy to install (you pull out the switch on the wall, and you put a small box in between the switch and the mains wiring), and you can control a whole circuit with one ~$40 switch. Depending on which one you get, they also support 3 and 4 way circuits (although with some caveats). And it comes with the additional benefits that it will always work with the manual switch (turning it off or on), and it will work with any lightbulbs you may want to use in the future, but the downside is that you can't really get full RGB colors in the bulbs if that's something you are going for.
  - rootusrootus 7y ago
    This is more or less my preferred solution. I use z-wave switches, not modules, though. I don't get RGB control, but I do get home automation that fails gracefully back to "works just like a light switch always did" if something goes wrong.
JohnJamesRambo 7y ago
I find teardowns like this fascinating. Especially in designs that are trying to do things as cheaply as possible.
- msisk6 7y ago
  You'll probably like the product teardowns of youtube user AvE. He usually does tools, but also the random appliance or product from time to time. His teardown of the Juicero is a classic: https://www.youtube.com/watch?v=_Cp-BGQfpHQ https://www.youtube.com/watch?v=_Cp-BGQfpHQ
gwbas1c 7y ago
> A fused neutral design would leave all of the bulb electronics hot. Strange. Makes me wonder if the resistor is really a fuse? BTW, I recently bought a plug -> bulb adapter on Amazon. It did not preserve neutral at all, and instead had a higher plastic ridge making it impossible to touch the metal part of the bulb. (The part that's at risk of touch, so it's typically connected to neutral.)
- gvb 7y ago
  No, it is not a fuse. It is most likely there to limit the inrush current into the cap when the power is applied.
- jacob019 7y ago
  I have often seen resistors used as fuses in cheap designs, but I have never seen a wirewound resistor used in this way. It is for current limiting to reduce peak load on the cheap components. Although it would probably be the next thing to blow if the IC failed short.
pfdietz 7y ago
The best thing about this bulb is that it isn't some internet-connected abomination.
- Someone1234 7y ago
  I'll take my "internet-connected abomination" over having to wire in a dimmer switch that might change the tone of the light as you dim, make buzzing sounds, cut out the light early, or shorten the lifespan of the bulb. Hue has been the first dimming system that actually works well. I have a few colored bulbs, but rarely need them, the biggest benefit to me (aside from automation: dusk auto-on/off) is dimming different shades of white/yellow. Great system that has no real analogue competition.
JoshGlazebrook 7y ago
Does anyone know where to find actual good LED bulbs? All of the Feit bulbs from Costco I bought eventually died within two years. I tried buying Phillips (non hue) off Amazon, and they are also starting to die in about a year to a year and a half. They really try to sell LED bulbs as lasting "forever", but in reality they seem to die just as fast.
- Someone1234 7y ago
  You might want to check your home for electrical issues (specifically spikes). I've yet to have a single LED light bulb die ever, some have already exceeded their supposed 10 year lifespan. And that's not one brand. I have GE bulbs, Philips (Hue and not), and random brands from Amazon.
  - 0xff00ffee 7y ago
    Same here. I put 2700K philips all over my house 5 years ago and I haven't had any issues, but I have no idea of the quality of the power coming into my house from my provider. (Anyone know how good Austin Energy's electricity on the west side is?)
  - JoshGlazebrook 7y ago
    This is at two separate apartments, and a standlone house. All of them seem to die.
    - amiantos 7y ago
      Gotta check your attitude, maybe it's disrupting the DeKalbs. (Sorry for the Heinlein reference, it was too tempting.)
  - bcrosby95 7y ago
    Were they selling cheap LED bulbs over 10 years ago? By my recollection they were all expensive back then. It seems plausible yours were expensive and higher quality than all the cheap ones everyone is buying nowadays. Speaking for myself, I've bought a variety of brands over the years. Some brands seem to die after a year or so. Others are still going fine after 3-5 years.
indiantinker 7y ago
$1.25? How about a 60c LED light bulb teardown :http://rohitg.in/2014/10/28/Dollar-LED-Bulb/ http://rohitg.in/2014/10/28/Dollar-LED-Bulb/
- OrgNet 7y ago
  at $0.60, it probably pays for itself in a few months... (energy costs)
kawfey 7y ago
As an amateur radio operator, I can hear the RFI generated from that cheap bulb just by looking at it. I upgraded my home from CFL to LED and found out the hard way that cheap IKEA bulbs are not conducive to a radio hobby. Philips Hue and Lifx have been generally much better.
- tigeba 7y ago
  I recently replaced a bunch of bulbs in my recording studio with LED and it was a huge mistake. They are basically RFI cannons. I removed them after realizing what was going on. I spent a couple of days hunting down a really nasty rogue noise and it ended up being a LIFX bulb I had forgotten about. Now I have to find a huge pile of black market incandescent bulbs...
- wglb 7y ago
  Not all LEDs are so good. I have under-the-counter LED lights that total the low bands when turned on.
lgleason 7y ago
My entire house has been converted over to LED. The cheaper the design the higher the failure rate. The heat seems to kill these things over time. For example I just ordered another warranty replacement from one brand called Hyperikon that uses similar types of designs for floods in my Kitchen. These have a much higher failure rate. Others seem to last forever. Between using electrolytic Capacitors and other tings that are prone to heat and small enclosed areas it is no wonder that the newer, cheaper bulbs fail quicker. Since one big reason for going with LED is to be more energy efficient and greener, it would be interesting to compare the carbon footprint of these cheap LED bulbs that fail quickly with an incandescent and CFL over the entire lifespan. If the bulb lasts longer the numbers are pretty easy, but given short lifespan of some and their use or rare earth elements it would be interesting to see the full analysis of the environmental impact of each one.
- detritus 7y ago
  I had pretty much this exact thought recently after a couple of LED bulbs failed in fairly close succession in my house, despite a purported 20/50K hour lifespan (I can't recall which exactly, but neither reached). They're own-brand ones, sold by a major supermarket chain here in the UK (Sainsburys), so I'd expect them to be 'ok' at least. Certainly not 'cheap'. Compared to ye olde incandescents, the complexity and material make up is significantly less recyclable and looks to my eye to require a lot more invested energy to manufacture. - I've wondered this about so-called 'smart meters' too - how much energy does it take to make one, and how long to 'pay off' that investment?
  - yjftsjthsd-h 7y ago
    Were smart meters about saving energy? I sorta assumed they were just there to make things easier on the power company. Although I suppose if it means that a person doesn't have to drive a car to every meter every month, that's probably a win.
    - bcrosby95 7y ago
      I think they can help with saving energy indirectly: by letting power companies give customers more detailed information about their usage. But I don't know how often people take advantage of this. I've shaved off around .15 kwh of energy that was used 24/7 ($25/month in California) based upon usage information from our energy company.
ThePhysicist 7y ago
It's pretty amazing how powerful small chip-on-board (COB) LED modules have become. I recently built a 6000 Lumen aquarium light with 7W - 850 Lumen COB modules. The active surface is just 5x5 mm, so the illuminance when held in front of your eye (1 cm² surface) is about 17.000.000 Lux, roughly 100 times brighter than direct sunlight on a summer's day at noon (so don't do it as it might be the last thing your see with that eye). And those modules are actually at the low end of the available power, you can get up to 35 W packaged into such a tiny COB, which is just crazy. Good thermal anchoring of the chips is therefore paramount, as they will quickly heat up to the point of being destroyed by electromigration if they're not properly cooled (and I imagine for the control electronics in the light bulb the high temperatures are also not beneficial). Anyway, it's still impressive how much light you can get out of such such tiny devices.
- bprater 7y ago
  This has impacted the video production business in a positive way over the last couple years. Previously, we had to put on gloves, find a 30 amp fuse and use hot tungsten lights to put together a production. Now folks are using high-quality LED-based lighting, running off battery power, and significantly smaller than a generation ago.
- Dylan16807 7y ago
  850 lumens per 5x5mm square isn't overly spooky. It's only about 1/50 as bright as the sun itself, and comfortably under the level where you risk burning spots on your retina. I'm not really sure what happens when you hold it right up to your eye. I'd be worried about the total amount of heat my retina can dissipate more than the lumens, but I have no idea what that number actually is.
  - ThePhysicist 7y ago
    It depends on the distance. Even at 1 m an 850 Lumen source with 120 degree radiation angle is painful to look at, and at 1 cm distance the illuminance is 10.000 times higher again. The peak illuminance of the sun at the surface of the earth is around 120.000 Lux (Lumen /m2), significantly smaller than such an LED when viewed from a short distance.
m0zg 7y ago
Has anyone here done any rigorous testing wrt flicker in particular? Of the reasonably priced brands (which excludes Hue), what's the lowest-flickering warm white bulb?
Animats 7y ago
Some designs eliminate the electrolytic capacitor. That's the first component to fail. If you want 10+ years of operation, it has to go. You can get rid of the electrolytic, but you have to add an inductor.[1] [1] https://led-driver.power.com/products/product-archive/linkswitch-pl/ https://led-driver.power.com/products/product-archive/linksw...
- philipkglass 7y ago
  The cheap bulb teardown linked to by indiantinker [1] shows that it contains a 100uf electrolytic cap for smoothing. A quick search shows that 6.3 V 100uf MLCC capacitors are readily available for ~20 cents. Maybe you can only afford that sort of thing starting in a "two dollar" bulb but it shouldn't require buying fancy $10 bulbs to ensure that the capacitors live as long as the LED. Or are there other considerations that mean non-electrolytic capacitors are unsuitable? [1] http://rohitg.in/2014/10/28/Dollar-LED-Bulb/ http://rohitg.in/2014/10/28/Dollar-LED-Bulb/
  - rcxdude 7y ago
    Well, for MLCC caps specifically, 6.3V is definitely not going to cut it (that's less than the voltage across 2 LEDs, and there will be more than that in series). You'll find that 100uf in 200V ceramic caps will be substantially more expensive ($10 - $100), plus you get fun effects like ceramic capacitors have less capacitance the higher the DC voltage across them. Electrolytics are used when you have no choice, and if you are trying to store a large amount of charge in a small volume (especially on the cheap), you have precious little options.
    - philipkglass 7y ago
      Thanks! I was thinking of a single LED. Looking at other teardowns where the actual light emitting elements are shown, I see that bulbs contain multiple LEDs.
  - Animats 7y ago
    This needs a 100V capacitor. 6.3V ceramic caps are easy to source, but not higher voltage devices. Multilayer ceramic capacitors for high voltages are still quite expensive.[1] Not available in surface mount, either. Energy stored is voltage x capacitance, and capacitor size and cost scales according. You have to store enough energy to light the bulb for half a power line cycle in something. If you used 3-phase power to light bulbs, no need for energy storage. 3-phase is always on; you just need a switching regulator to smooth out the ripple. Some large arena lights work that way. Not worth the trouble at home scale. [1] http://www.chemi-con.co.jp/e/catalog/pdf/ce-e/ce-sepa-e/ce-ntd-e-2019.pdf http://www.chemi-con.co.jp/e/catalog/pdf/ce-e/ce-sepa-e/ce-n...
Zod666 7y ago
Not knowing much about less, are any of these cheap ones just as good as the premium ones? I'd also like a bulb that could be changed to an orangish hue at night to block out blue light. From what I read a lot of them emit little light when changed to orange.
ericol 7y ago
In my experience, the electronics _around_ the leds tend to fail rather fast. Few years back - around 7 - we expanded our house slightly (A room, a small living room and a small bath) so I put led bulbs in there, plus I replaced some of the bulbs in the rest of the house. As I bought several of these (5+) when I placed them I wrote on them with a permanent marker the date of installation. Bear in mind these were not extra cheap, more like mid priced ones. 6 months from installation I had to start replacing them, and at the 18 months mark I had replaced most of them. Bear in mind this coincided with a big legislation in my country that made "normal" light bulbs illegal (Because ecology, global warming and shit). I doubt they took into account how much trash these cheap bulbs generate. Also, whatever money you save from less energy consumption is probably a lot less than the money that it costs replacing them this often.
basicplus2 7y ago
It would be better to run a dc circuit throughout a house just for lights and do away with the rectifier circuits inside these led globes and It could be free of transients.
- londons_explore 7y ago
  I'm all for DC supplies in houses, but it doesn't quite solve the issue here. Any DC house-wide bus would see voltage drop along the wires, so all connected devices would have to handle an acceptable voltage range. Since LED's have a very steep IV curve, they really need either current control or a very big resistor to handle that voltage variation. Very big resistor = too much heat. So current control. And the only realistic way to achieve that is with a switched mode power supply. There is one benefit left for DC: The switched mode power supply could have much smaller input and output capacitors, and operate at much higher frequencies, therefore being much smaller.
  - Dylan16807 7y ago
    It solves the problem of your power disappearing every eight milliseconds. No rectifier, no higher voltages, the ability to use capacitors that are a thousand times smaller. And even if you did use a resistor, it wouldn't have to be too wasteful. If you use normal 14 gauge wiring, your resistance is probably half an ohm. At 48 volts, with a dozen 60-watt equivalent bulbs, your voltage drop is less than one volt.
sjg007 7y ago
I wonder if we will get to a point where new houses will have DC wired LED lights with a central converter. Seems no reason not to do so.
- samatman 7y ago
  There is reason not to do so: Ohm's law. Low voltage requires low resistance to transmit reasonable current. The only way to get this is with substantially thicker wiring. 5V DC isn't a plausible voltage to send the distance from a fusebox to light installations. One could do 48V and step it down at the site, but there's not much in the way of gains to be had. AC/DC circuits are quite efficient as-is.
  - sjg007 7y ago
    Why is PoE so popular then?
    - samatman 7y ago
      > PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA[2][3]) on each port.[4] Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable. 84% efficiency sucks. It's a reasonable solution for some cases, because if you're running Ethernet to a camera already, hey, why not provide some power? But for, let's say 300W of lighting that runs 12 hours a day, you're wasting about 15kWh of electricity per month. Residential wiring has internal losses under 1%. I would rather not.
    - Gibbon1 7y ago
      PoE is popular because electricians are expensive. That said I think there is a lot of potential to use the newer higher power PoE standards or similar for smart houses. The newer standard go up to 100W. One thing about efficiency is low voltage DC/DC converters are always fighting for efficiency. It's much less of a problem for higher voltage DC/DC's. This is due to fixed voltage drops and I squared R losses.
- quickthrowman 7y ago
anonsivalley652 7y ago
Dave at EEVblog just toredown a BenQ freebie monitor nightlight the other day, maybe yesterday IIRC. Also, Bigclive as mentioned. The hotdogger and USB charger with shoddy transformers passing 240V should make any sane person to realize it's cheaper to stick to name-brand USB chargers. Disclaimer: Many moons ago, I was literally tearing-apart clocks and electronics when I was 5. Too bad I didn't have a Youtube channel. ;-) I think it's genetic as my father and grandfather both built a bunch of HeathKit projects.
fyfy18 7y ago
> A fuse should be put on the hot leg as close to the power entry as possible. The reasoning being that if the fuse pops it removes the hot voltage from as much of the assembly as possible. This only works if the power system has a defined neutral and live wire. European Schuko plugs do not - as the plugs are reversible - so you need to break both wires to safely cut power to the device.
Zak 7y ago
I don't think this is the design for the next hundred years as the author claims. Instead, screw-in bulbs based on a form factor dictated by 19th century glass making techniques and incandescent lighting will probably die out. They'll surely be available as a specialty item, but cramming a power supply, emitters, and heatsink into such a suboptimal package only makes sense for legacy compatibility.
- dcwca 7y ago
  Do you see new lighting wiring standards emerging anywhere right now? Are they gaining traction?
  - tialaramex 7y ago
    Integrating a non-replaceable lamp is the trend. You buy the whole unit, it works for say, ten years and then you buy a different one when remodelling. This made no sense when a light bulb was just something that needs replacing every few months in normal use but LEDs mean you can engineer that out. Replacing a "light bulb" will seem as weird as replacing the backlight inside your laptop. Obviously a technician can do it, might even make sense to pay for that rather than buy a replacement for the whole unit, but it's not something regular people do themselves.
  - Zak 7y ago
    New wiring standards are not necessary. The most popular successor is as tialaramex described, an integrated lamp hardwired into AC power. For more sophisticated users, AC/DC power conversion, power regulation/dimming, and the LEDs themselves can all be separate components. This allows more customization, and the possibility of replacing individual components when something fails. Personally, I've been using Viltrox brand photo/video lights for interior lighting lately. These combine two sets of LEDs in different color temperatures with dimming/regulation, and an external AC to DC power supply. These have much better color rendering than most consumer stuff, and I like having adjustable color temperature. The bigger ones have remote controls, so hanging one from the ceiling is possible while retaining access to all of its functions.
Scoundreller 7y ago
So what’s a solution? Bulbs filled with a non-conducting non-flammable liquid? Should cheaply provide better heat dissipation than air, no?
jaclaz 7y ago
If we can for a moment digress from light bulbs, I have had recently some experience with (el-cheapo) led panels, those that can be inserted in ceilings (false ceilings), they can be either round or square and are typically 12 W (around 17 cm diameter) and 18 W (around 22 cm in diameter), there are even larger ones (24 W/30 cm diameter). They make a very good amount of light, like 1100 lumens for the 12 W and 1650 lumens for the 18 W, and have a separate "led driver", constant current, 280-300 mA, voltage 36-72 V for the 12/18 W driver and 54 - 96 V for the 18/24 W driver. They can be found everywhere for anything between 4 and 10 Euro each. It is now three years I installed some 60 of them (in a restaurant/hotel, think no less than 10 h/day on for 300 days/year) and 15-20% of them failed in the last few months. In ALL of them the faulty part is the "driver" (which basically is a transformer and a rectifier plus a current limiting chip and a capacitor, which seemingly is the actual component that always fails[1]), spares (a new driver) can be luckily be found for 2 or 3 Euro each, the actual leds are perfect. I cannot see why it is not in production a male/female E27 attachment containing a "driver" and a "driverless" bulb to match. The amount of electronics thrown away would at least halve. [1] See: https://www.youtube.com/watch?v=mS0Jetfw4vA https://www.youtube.com/watch?v=mS0Jetfw4vA
scargill 7y ago
I'm glad I found this and of course I'm familiar with Big Clive (I watch his stuff regularly), EEVBlog and others mentioned here.I've had mixed success with low-cost LED lighting and often discuss that and related subjects on my own blog at https://tech.scargill.net https://tech.scargill.net as well as reading what others have to say. I get a lot of feedback on that subject. I note comment below about Poundland. Related to that (I guess) is PoundStretcher and up to now, the highest failure rate I've had in LED mains lighting are the bargain LED lamps (Hitachi) from Poundstretcher (and I get samples or buy LED lights from China, Europe and various locations in the UK so I'm no stranger to the subject).
atesti 7y ago
I don't understand these direct AC drivers: https://www.electronicsweekly.com/news/why-not-direct-ac-drive-your-led-string-2016-04/ https://www.electronicsweekly.com/news/why-not-direct-ac-dri... They activate 1-4 LEDs in series depending on where in the half wave of the 120V AC we are. That's understandable, but I don't get how about 60V is okay for one LED? One LED has a forward current of max. 3V, doesn't it? By partitioning the up to 120V into 4 phases, it does not cover a mere 4 LEDs in series. Do they have to put 15 in series for the first section in the schematics and another 15 for the thign called "LED 2", etc.? Are there LEDs with forward currents of 60V available?

324 points by teucris 7y ago

WrtCdEvrydy 7y ago

I love seeing designs that fail while keeping the product as electrically hot as possible - said noone ever.

ygra 7y ago
Oh, Big Clive might say something to that effect, I'm sure.

baybal2 7y ago

> A fused neutral design would leave all of the bulb electronics hot. Strange. Depends on what country you are living in. It's not new for me to see a product passing safety certification in one country, failing in another, but still ending up in it because of messup by people running the OEM industry. Second to it, in a normal country, for an electrical appliance, failing short, and triggering a short circuit protection is a relatively safe alternative to having a dedicated fail safe circuit, but in countries with building codes not saying anything about wiring safety, it often means a fire.

cotillion 7y ago
Considering how popular unpolarized plugs are all over the world I don't think a fused neutral is much of a problem in a lamp.
tinus_hn 7y ago
Anyway European Schuko plugs are not even polarized, there is no way to know which wire is hot.
- gwbas1c 7y ago
  Honestly, I think it's better that we view polarization as a historical oddity. So many people don't understand the concept. Even I have trouble understanding the real difference between ground and neutral, because neutral connects to ground in the breaker panel. I'm not even sure if neutral goes through the breaker?
  - ars 7y ago
    Neutral exists separately from ground only because if there is some residual resistance in the line, there will be voltage on the neutral. So you have a separate ground that normally sees no voltage at all. You are correct, the neutral does not go through the breaker. It is usually wired inside the breaker panel though. Some localities want the neutral and ground wired separately (to separate bus bars), with a single point connecting them, but most don't care and the neutral and ground are attached to the exact same place inside the breaker panel. Electrically, the neutral and ground are at the same potential, assuming magic wires with zero resistance, but in the real world the wire does have resistance, especially if it was poorly installed, so they are not always at the same potential. There could also be capacitance in the line.
  - rootusrootus 7y ago
    The neutral handles the expected load, while the ground is designed specifically to be an alternate current path from the case (assuming it is conductive) that has low resistance and will immediately flow enough current to trip the breaker in case the hot somehow comes into contact with the case. Neutral does not go through the breaker, correct.
  - zAy0LfpBZLC8mAC 7y ago
    The purpose of separate wires is twofold: 1. It's to provide protection in case of neutral failure. If you have an appliance with the case grounded via neutral and the neutral wiring fails, you now have the case connected to live (through any appliance that is switched on). With separate ground, nothing happens as you are only allowed to connect ground to neutral at a point where failure of the upstream wiring is practically impossible (i.e., wires so thick that they practically won't break). 2. It's to provide a path for ground fault currents that does not pass through the RCD, if you have an RCD. While neutral doesn't go through the circuit breaker, it does go through the RCD, so as to measure the difference in current between live and neutral. If your appliance is grounded vial neutral, any ground fault (connection from live to the case) looks like regular load current to the RCD, if it is grounded via separate ground, the fault current bypasses the RCD and thus causes it to trigger, even for a small current that would not trigger over current protection.

spookthesunset 7y ago

Some of these cheap LED bulbs have horrible flicker. For a fun time, record a slow motion video of a cheap bulb on your phone and play it back. Like half the damn video is black (pretty sure it is because they literally chop out half the AC sine wave with a diode). LED Christmas lights are also really bad. Then compare it to something like a Phillips hue bulb. The difference between the two is pretty big. On a side note I sometimes wonder if other animals have a quicker “refresh rate” on their eyes and see nothing but very visible flicker on these bad LED bulbs. I also wonder if some animals could see the raster scan in action on old CRTs...

all_usernames 7y ago
Dogs apparently have a visual sample rate of around 75Hz, meaning they wouldn't see much in an old analog TV, but newer HDTVs might look realistic to them. https://thebark.com/content/heres-what-dogs-see-when-they-watch-television https://thebark.com/content/heres-what-dogs-see-when-they-wa...
- berdon 7y ago
  Our two dogs watch our 4k TV often. And bark at various things, actors, subjects they don't like.
  - Topgamer7 7y ago
    Had a dog that would press her nose right up to an ipad screen and move her face around to follow the squirrel, bird, or dog that interested her. She would get very excited about it. She also watched TV. At one point sitting on hind legs trying to elevate off the bed to be inline with the center of the image.
  - bradstewart 7y ago
    Only one of my dogs appears to recognize things in the TV. She'll bark at something on screen, and my other dog will run to a window or door trying to figure what he missed. Always wondered why...
- 7y ago

petercooper 7y ago

If, for some reason, lighting teardowns are a fascination of yours, I thought I should mention "bigclive", a YouTube channel devoted to this very topic :-D https://www.youtube.com/user/bigclivedotcom/videos https://www.youtube.com/user/bigclivedotcom/videos (the author of this blog post also has a channel at https://www.youtube.com/user/electronupdate/videos https://www.youtube.com/user/electronupdate/videos )

jcims 7y ago
Indeed! Also https://www.youtube.com/user/mikeselectricstuff/videos https://www.youtube.com/user/mikeselectricstuff/videos for lighting and scrap medical/industrial equipment teardowns. If you are into RF dark magic, https://www.youtube.com/user/TheSignalPathBlog/videos https://www.youtube.com/user/TheSignalPathBlog/videos for teardowns (and repairs!) of GHz scopes, network analyzers, etc.
ASalazarMX 7y ago
Never expected to see cheese and electronic teardowns mixed.
- teh_klev 7y ago
  That whole stuffing 240v into a BabyBel cheese and Co-op mincemeat pies thing was quite amusing, I guess the festive season can be "slow news" days even for video bloggers. That said, back in the early 90's when I was a field engineer, a mate and myself used apply 240v to foodstuffs in the company workshop "just to see what happened" when things were a bit slow. The resulting smells were somewhat odd.
  - petercooper 7y ago
    Have you ever seen "PhotonicInduction"? He did a lot of very dangerous and borderline insane stuff with electricity like running up a 20KW bulb in his house: https://www.youtube.com/watch?v=LT5_-A0m8_U https://www.youtube.com/watch?v=LT5_-A0m8_U (or, more famously, chucking a cinder block into a washing machine)

burgerquizz 7y ago

Hijacking the comments. I have a project that would involve about 15+ smart Lightbulbs. Anyone would know any decent/cheaper alternative to the Phillips Hue bulbs?

mlonkibjuyhv 7y ago
Check Ikea
ChuckNorris89 7y ago
Xiaomi Yeelight
vassie 7y ago
These videos compare a few on offer... https://www.youtube.com/watch?v=osauwVoP4a8 https://www.youtube.com/watch?v=osauwVoP4a8 https://www.youtube.com/watch?v=-ZPo7C3PDT4 https://www.youtube.com/watch?v=-ZPo7C3PDT4 I also highly recommend the Smart Home Solver YouTube channel if you're interested in home automation https://www.youtube.com/channel/UCwOBG77Tm8cE24FPxHb_abw https://www.youtube.com/channel/UCwOBG77Tm8cE24FPxHb_abw
Klathmon 7y ago
Think outside the box (outside the bulb?) z-wave "behind the switch" modules are super easy to install (you pull out the switch on the wall, and you put a small box in between the switch and the mains wiring), and you can control a whole circuit with one ~$40 switch. Depending on which one you get, they also support 3 and 4 way circuits (although with some caveats). And it comes with the additional benefits that it will always work with the manual switch (turning it off or on), and it will work with any lightbulbs you may want to use in the future, but the downside is that you can't really get full RGB colors in the bulbs if that's something you are going for.
- rootusrootus 7y ago
  This is more or less my preferred solution. I use z-wave switches, not modules, though. I don't get RGB control, but I do get home automation that fails gracefully back to "works just like a light switch always did" if something goes wrong.

JohnJamesRambo 7y ago

I find teardowns like this fascinating. Especially in designs that are trying to do things as cheaply as possible.

msisk6 7y ago
You'll probably like the product teardowns of youtube user AvE. He usually does tools, but also the random appliance or product from time to time. His teardown of the Juicero is a classic: https://www.youtube.com/watch?v=_Cp-BGQfpHQ https://www.youtube.com/watch?v=_Cp-BGQfpHQ

gwbas1c 7y ago

> A fused neutral design would leave all of the bulb electronics hot. Strange. Makes me wonder if the resistor is really a fuse? BTW, I recently bought a plug -> bulb adapter on Amazon. It did not preserve neutral at all, and instead had a higher plastic ridge making it impossible to touch the metal part of the bulb. (The part that's at risk of touch, so it's typically connected to neutral.)

gvb 7y ago
No, it is not a fuse. It is most likely there to limit the inrush current into the cap when the power is applied.
jacob019 7y ago
I have often seen resistors used as fuses in cheap designs, but I have never seen a wirewound resistor used in this way. It is for current limiting to reduce peak load on the cheap components. Although it would probably be the next thing to blow if the IC failed short.

pfdietz 7y ago

The best thing about this bulb is that it isn't some internet-connected abomination.

Someone1234 7y ago
I'll take my "internet-connected abomination" over having to wire in a dimmer switch that might change the tone of the light as you dim, make buzzing sounds, cut out the light early, or shorten the lifespan of the bulb. Hue has been the first dimming system that actually works well. I have a few colored bulbs, but rarely need them, the biggest benefit to me (aside from automation: dusk auto-on/off) is dimming different shades of white/yellow. Great system that has no real analogue competition.

JoshGlazebrook 7y ago

Does anyone know where to find actual good LED bulbs? All of the Feit bulbs from Costco I bought eventually died within two years. I tried buying Phillips (non hue) off Amazon, and they are also starting to die in about a year to a year and a half. They really try to sell LED bulbs as lasting "forever", but in reality they seem to die just as fast.

Someone1234 7y ago
You might want to check your home for electrical issues (specifically spikes). I've yet to have a single LED light bulb die ever, some have already exceeded their supposed 10 year lifespan. And that's not one brand. I have GE bulbs, Philips (Hue and not), and random brands from Amazon.
- 0xff00ffee 7y ago
  Same here. I put 2700K philips all over my house 5 years ago and I haven't had any issues, but I have no idea of the quality of the power coming into my house from my provider. (Anyone know how good Austin Energy's electricity on the west side is?)
- JoshGlazebrook 7y ago
  This is at two separate apartments, and a standlone house. All of them seem to die.
  - amiantos 7y ago
    Gotta check your attitude, maybe it's disrupting the DeKalbs. (Sorry for the Heinlein reference, it was too tempting.)
- bcrosby95 7y ago
  Were they selling cheap LED bulbs over 10 years ago? By my recollection they were all expensive back then. It seems plausible yours were expensive and higher quality than all the cheap ones everyone is buying nowadays. Speaking for myself, I've bought a variety of brands over the years. Some brands seem to die after a year or so. Others are still going fine after 3-5 years.

indiantinker 7y ago

$1.25? How about a 60c LED light bulb teardown :http://rohitg.in/2014/10/28/Dollar-LED-Bulb/ http://rohitg.in/2014/10/28/Dollar-LED-Bulb/

OrgNet 7y ago
at $0.60, it probably pays for itself in a few months... (energy costs)

kawfey 7y ago

As an amateur radio operator, I can hear the RFI generated from that cheap bulb just by looking at it. I upgraded my home from CFL to LED and found out the hard way that cheap IKEA bulbs are not conducive to a radio hobby. Philips Hue and Lifx have been generally much better.

tigeba 7y ago
I recently replaced a bunch of bulbs in my recording studio with LED and it was a huge mistake. They are basically RFI cannons. I removed them after realizing what was going on. I spent a couple of days hunting down a really nasty rogue noise and it ended up being a LIFX bulb I had forgotten about. Now I have to find a huge pile of black market incandescent bulbs...
wglb 7y ago
Not all LEDs are so good. I have under-the-counter LED lights that total the low bands when turned on.

lgleason 7y ago

My entire house has been converted over to LED. The cheaper the design the higher the failure rate. The heat seems to kill these things over time. For example I just ordered another warranty replacement from one brand called Hyperikon that uses similar types of designs for floods in my Kitchen. These have a much higher failure rate. Others seem to last forever. Between using electrolytic Capacitors and other tings that are prone to heat and small enclosed areas it is no wonder that the newer, cheaper bulbs fail quicker. Since one big reason for going with LED is to be more energy efficient and greener, it would be interesting to compare the carbon footprint of these cheap LED bulbs that fail quickly with an incandescent and CFL over the entire lifespan. If the bulb lasts longer the numbers are pretty easy, but given short lifespan of some and their use or rare earth elements it would be interesting to see the full analysis of the environmental impact of each one.

detritus 7y ago
I had pretty much this exact thought recently after a couple of LED bulbs failed in fairly close succession in my house, despite a purported 20/50K hour lifespan (I can't recall which exactly, but neither reached). They're own-brand ones, sold by a major supermarket chain here in the UK (Sainsburys), so I'd expect them to be 'ok' at least. Certainly not 'cheap'. Compared to ye olde incandescents, the complexity and material make up is significantly less recyclable and looks to my eye to require a lot more invested energy to manufacture. - I've wondered this about so-called 'smart meters' too - how much energy does it take to make one, and how long to 'pay off' that investment?
- yjftsjthsd-h 7y ago
  Were smart meters about saving energy? I sorta assumed they were just there to make things easier on the power company. Although I suppose if it means that a person doesn't have to drive a car to every meter every month, that's probably a win.
  - bcrosby95 7y ago
    I think they can help with saving energy indirectly: by letting power companies give customers more detailed information about their usage. But I don't know how often people take advantage of this. I've shaved off around .15 kwh of energy that was used 24/7 ($25/month in California) based upon usage information from our energy company.

ThePhysicist 7y ago

It's pretty amazing how powerful small chip-on-board (COB) LED modules have become. I recently built a 6000 Lumen aquarium light with 7W - 850 Lumen COB modules. The active surface is just 5x5 mm, so the illuminance when held in front of your eye (1 cm² surface) is about 17.000.000 Lux, roughly 100 times brighter than direct sunlight on a summer's day at noon (so don't do it as it might be the last thing your see with that eye). And those modules are actually at the low end of the available power, you can get up to 35 W packaged into such a tiny COB, which is just crazy. Good thermal anchoring of the chips is therefore paramount, as they will quickly heat up to the point of being destroyed by electromigration if they're not properly cooled (and I imagine for the control electronics in the light bulb the high temperatures are also not beneficial). Anyway, it's still impressive how much light you can get out of such such tiny devices.

bprater 7y ago
This has impacted the video production business in a positive way over the last couple years. Previously, we had to put on gloves, find a 30 amp fuse and use hot tungsten lights to put together a production. Now folks are using high-quality LED-based lighting, running off battery power, and significantly smaller than a generation ago.
Dylan16807 7y ago
850 lumens per 5x5mm square isn't overly spooky. It's only about 1/50 as bright as the sun itself, and comfortably under the level where you risk burning spots on your retina. I'm not really sure what happens when you hold it right up to your eye. I'd be worried about the total amount of heat my retina can dissipate more than the lumens, but I have no idea what that number actually is.
- ThePhysicist 7y ago
  It depends on the distance. Even at 1 m an 850 Lumen source with 120 degree radiation angle is painful to look at, and at 1 cm distance the illuminance is 10.000 times higher again. The peak illuminance of the sun at the surface of the earth is around 120.000 Lux (Lumen /m2), significantly smaller than such an LED when viewed from a short distance.

m0zg 7y ago

Has anyone here done any rigorous testing wrt flicker in particular? Of the reasonably priced brands (which excludes Hue), what's the lowest-flickering warm white bulb?

Animats 7y ago

Some designs eliminate the electrolytic capacitor. That's the first component to fail. If you want 10+ years of operation, it has to go. You can get rid of the electrolytic, but you have to add an inductor.[1] [1] https://led-driver.power.com/products/product-archive/linkswitch-pl/ https://led-driver.power.com/products/product-archive/linksw...

philipkglass 7y ago
The cheap bulb teardown linked to by indiantinker [1] shows that it contains a 100uf electrolytic cap for smoothing. A quick search shows that 6.3 V 100uf MLCC capacitors are readily available for ~20 cents. Maybe you can only afford that sort of thing starting in a "two dollar" bulb but it shouldn't require buying fancy $10 bulbs to ensure that the capacitors live as long as the LED. Or are there other considerations that mean non-electrolytic capacitors are unsuitable? [1] http://rohitg.in/2014/10/28/Dollar-LED-Bulb/ http://rohitg.in/2014/10/28/Dollar-LED-Bulb/
- rcxdude 7y ago
  Well, for MLCC caps specifically, 6.3V is definitely not going to cut it (that's less than the voltage across 2 LEDs, and there will be more than that in series). You'll find that 100uf in 200V ceramic caps will be substantially more expensive ($10 - $100), plus you get fun effects like ceramic capacitors have less capacitance the higher the DC voltage across them. Electrolytics are used when you have no choice, and if you are trying to store a large amount of charge in a small volume (especially on the cheap), you have precious little options.
  - philipkglass 7y ago
    Thanks! I was thinking of a single LED. Looking at other teardowns where the actual light emitting elements are shown, I see that bulbs contain multiple LEDs.
- Animats 7y ago
  This needs a 100V capacitor. 6.3V ceramic caps are easy to source, but not higher voltage devices. Multilayer ceramic capacitors for high voltages are still quite expensive.[1] Not available in surface mount, either. Energy stored is voltage x capacitance, and capacitor size and cost scales according. You have to store enough energy to light the bulb for half a power line cycle in something. If you used 3-phase power to light bulbs, no need for energy storage. 3-phase is always on; you just need a switching regulator to smooth out the ripple. Some large arena lights work that way. Not worth the trouble at home scale. [1] http://www.chemi-con.co.jp/e/catalog/pdf/ce-e/ce-sepa-e/ce-ntd-e-2019.pdf http://www.chemi-con.co.jp/e/catalog/pdf/ce-e/ce-sepa-e/ce-n...

Zod666 7y ago

Not knowing much about less, are any of these cheap ones just as good as the premium ones? I'd also like a bulb that could be changed to an orangish hue at night to block out blue light. From what I read a lot of them emit little light when changed to orange.

ericol 7y ago

In my experience, the electronics _around_ the leds tend to fail rather fast. Few years back - around 7 - we expanded our house slightly (A room, a small living room and a small bath) so I put led bulbs in there, plus I replaced some of the bulbs in the rest of the house. As I bought several of these (5+) when I placed them I wrote on them with a permanent marker the date of installation. Bear in mind these were not extra cheap, more like mid priced ones. 6 months from installation I had to start replacing them, and at the 18 months mark I had replaced most of them. Bear in mind this coincided with a big legislation in my country that made "normal" light bulbs illegal (Because ecology, global warming and shit). I doubt they took into account how much trash these cheap bulbs generate. Also, whatever money you save from less energy consumption is probably a lot less than the money that it costs replacing them this often.

basicplus2 7y ago

It would be better to run a dc circuit throughout a house just for lights and do away with the rectifier circuits inside these led globes and It could be free of transients.

londons_explore 7y ago
I'm all for DC supplies in houses, but it doesn't quite solve the issue here. Any DC house-wide bus would see voltage drop along the wires, so all connected devices would have to handle an acceptable voltage range. Since LED's have a very steep IV curve, they really need either current control or a very big resistor to handle that voltage variation. Very big resistor = too much heat. So current control. And the only realistic way to achieve that is with a switched mode power supply. There is one benefit left for DC: The switched mode power supply could have much smaller input and output capacitors, and operate at much higher frequencies, therefore being much smaller.
- Dylan16807 7y ago
  It solves the problem of your power disappearing every eight milliseconds. No rectifier, no higher voltages, the ability to use capacitors that are a thousand times smaller. And even if you did use a resistor, it wouldn't have to be too wasteful. If you use normal 14 gauge wiring, your resistance is probably half an ohm. At 48 volts, with a dozen 60-watt equivalent bulbs, your voltage drop is less than one volt.

sjg007 7y ago

I wonder if we will get to a point where new houses will have DC wired LED lights with a central converter. Seems no reason not to do so.

samatman 7y ago
There is reason not to do so: Ohm's law. Low voltage requires low resistance to transmit reasonable current. The only way to get this is with substantially thicker wiring. 5V DC isn't a plausible voltage to send the distance from a fusebox to light installations. One could do 48V and step it down at the site, but there's not much in the way of gains to be had. AC/DC circuits are quite efficient as-is.
- sjg007 7y ago
  Why is PoE so popular then?
  - samatman 7y ago
    > PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA[2][3]) on each port.[4] Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable. 84% efficiency sucks. It's a reasonable solution for some cases, because if you're running Ethernet to a camera already, hey, why not provide some power? But for, let's say 300W of lighting that runs 12 hours a day, you're wasting about 15kWh of electricity per month. Residential wiring has internal losses under 1%. I would rather not.
  - Gibbon1 7y ago
    PoE is popular because electricians are expensive. That said I think there is a lot of potential to use the newer higher power PoE standards or similar for smart houses. The newer standard go up to 100W. One thing about efficiency is low voltage DC/DC converters are always fighting for efficiency. It's much less of a problem for higher voltage DC/DC's. This is due to fixed voltage drops and I squared R losses.
quickthrowman 7y ago

anonsivalley652 7y ago

Dave at EEVblog just toredown a BenQ freebie monitor nightlight the other day, maybe yesterday IIRC. Also, Bigclive as mentioned. The hotdogger and USB charger with shoddy transformers passing 240V should make any sane person to realize it's cheaper to stick to name-brand USB chargers. Disclaimer: Many moons ago, I was literally tearing-apart clocks and electronics when I was 5. Too bad I didn't have a Youtube channel. ;-) I think it's genetic as my father and grandfather both built a bunch of HeathKit projects.

fyfy18 7y ago

> A fuse should be put on the hot leg as close to the power entry as possible. The reasoning being that if the fuse pops it removes the hot voltage from as much of the assembly as possible. This only works if the power system has a defined neutral and live wire. European Schuko plugs do not - as the plugs are reversible - so you need to break both wires to safely cut power to the device.

Zak 7y ago

I don't think this is the design for the next hundred years as the author claims. Instead, screw-in bulbs based on a form factor dictated by 19th century glass making techniques and incandescent lighting will probably die out. They'll surely be available as a specialty item, but cramming a power supply, emitters, and heatsink into such a suboptimal package only makes sense for legacy compatibility.

dcwca 7y ago
Do you see new lighting wiring standards emerging anywhere right now? Are they gaining traction?
- tialaramex 7y ago
  Integrating a non-replaceable lamp is the trend. You buy the whole unit, it works for say, ten years and then you buy a different one when remodelling. This made no sense when a light bulb was just something that needs replacing every few months in normal use but LEDs mean you can engineer that out. Replacing a "light bulb" will seem as weird as replacing the backlight inside your laptop. Obviously a technician can do it, might even make sense to pay for that rather than buy a replacement for the whole unit, but it's not something regular people do themselves.
- Zak 7y ago
  New wiring standards are not necessary. The most popular successor is as tialaramex described, an integrated lamp hardwired into AC power. For more sophisticated users, AC/DC power conversion, power regulation/dimming, and the LEDs themselves can all be separate components. This allows more customization, and the possibility of replacing individual components when something fails. Personally, I've been using Viltrox brand photo/video lights for interior lighting lately. These combine two sets of LEDs in different color temperatures with dimming/regulation, and an external AC to DC power supply. These have much better color rendering than most consumer stuff, and I like having adjustable color temperature. The bigger ones have remote controls, so hanging one from the ceiling is possible while retaining access to all of its functions.

Scoundreller 7y ago

So what’s a solution? Bulbs filled with a non-conducting non-flammable liquid? Should cheaply provide better heat dissipation than air, no?

jaclaz 7y ago

If we can for a moment digress from light bulbs, I have had recently some experience with (el-cheapo) led panels, those that can be inserted in ceilings (false ceilings), they can be either round or square and are typically 12 W (around 17 cm diameter) and 18 W (around 22 cm in diameter), there are even larger ones (24 W/30 cm diameter). They make a very good amount of light, like 1100 lumens for the 12 W and 1650 lumens for the 18 W, and have a separate "led driver", constant current, 280-300 mA, voltage 36-72 V for the 12/18 W driver and 54 - 96 V for the 18/24 W driver. They can be found everywhere for anything between 4 and 10 Euro each. It is now three years I installed some 60 of them (in a restaurant/hotel, think no less than 10 h/day on for 300 days/year) and 15-20% of them failed in the last few months. In ALL of them the faulty part is the "driver" (which basically is a transformer and a rectifier plus a current limiting chip and a capacitor, which seemingly is the actual component that always fails[1]), spares (a new driver) can be luckily be found for 2 or 3 Euro each, the actual leds are perfect. I cannot see why it is not in production a male/female E27 attachment containing a "driver" and a "driverless" bulb to match. The amount of electronics thrown away would at least halve. [1] See: https://www.youtube.com/watch?v=mS0Jetfw4vA https://www.youtube.com/watch?v=mS0Jetfw4vA

scargill 7y ago

I'm glad I found this and of course I'm familiar with Big Clive (I watch his stuff regularly), EEVBlog and others mentioned here.I've had mixed success with low-cost LED lighting and often discuss that and related subjects on my own blog at https://tech.scargill.net https://tech.scargill.net as well as reading what others have to say. I get a lot of feedback on that subject. I note comment below about Poundland. Related to that (I guess) is PoundStretcher and up to now, the highest failure rate I've had in LED mains lighting are the bargain LED lamps (Hitachi) from Poundstretcher (and I get samples or buy LED lights from China, Europe and various locations in the UK so I'm no stranger to the subject).

atesti 7y ago

I don't understand these direct AC drivers: https://www.electronicsweekly.com/news/why-not-direct-ac-drive-your-led-string-2016-04/ https://www.electronicsweekly.com/news/why-not-direct-ac-dri... They activate 1-4 LEDs in series depending on where in the half wave of the 120V AC we are. That's understandable, but I don't get how about 60V is okay for one LED? One LED has a forward current of max. 3V, doesn't it? By partitioning the up to 120V into 4 phases, it does not cover a mere 4 LEDs in series. Do they have to put 15 in series for the first section in the schematics and another 15 for the thign called "LED 2", etc.? Are there LEDs with forward currents of 60V available?