Teardown of a $1.25 LED Lightbulb
electronupdate.blogspot.com
electronupdate.blogspot.com
Also 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 for teardowns (and repairs!) of GHz scopes, network analyzers, etc.
See the pinned comment on:
Video:
https://www.youtube.com/watch?v=H66Fbg9nrk4
Clive's comment:
https://www.youtube.com/watch?v=H66Fbg9nrk4&lc=UgyLpu-CcVthk...
"The best bit about this video is seeing you plug a 120V appliance into 240V without realising it, and then watching the horror unfold as the grossly overloaded appliance makes loud stressed noises and emits flames. The appliance doesn't just run at twice it's normal power, it's closer to four times the power. Good job. Very entertaining."
I've followed Big Clive for about 5 years now and he's a great presenter. Especially his "what cheap shite I bought from my local Poundland on the Isle of Man" videos...which actually kinda reassure you that Poundland's "cheapo" electrics aren't that terrible or are going to burn your house down.
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.
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.
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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?
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.
Downside is that we're a decade into net-connected thermostat and HVAC systems and none of them support any of this.
Alternatively, plastic takes about 100 kJ/g to produce. So if the bulb has 1 g of plastic, that's about 0.03 kWh of energy. Nothing compared to the savings in electricity using it.
Not always, they could be subsidized to get people off of incandescents.
All the heat that comes out of a lightbulb is being generated at 100% efficiency :)
(Although it's likely more expensive to heat your home electrically instead of via natural gas)
“efficiency” is meaningless when heat is desired. if you pump 100W into a device, and it “wastes” all that power, you have successfully generated 100W of heat. only heat pumps can be more efficient.
Exactly. And if you have a whole house/apartment electric heating system it is very likely that it is in fact heat pump based. So you are better off using that for heat than the lights.
If your whole house/apartment heating system is gas or oil based, that will probably be even cheaper than the heat pump electric version.
Hmm, where? I have never knowingly been in a house with a heat pump in the UK, and lots of cheaper flats have electric radiators and immersion heaters.
Anyway, my point is that the inefficiency lost to "waste heat" is not 100% waste.
During the summer, it's also extra inefficient to pump 100W into a device producing heat and then pump even more power somewhere else to cool down the room.
They were a dollar Canadian after government incentive. You get what you pay for.
Prior technologies have expected failure built in. An incandescent bulb's filament will fail eventually (making the filament more robust reduces light output so now your bulb lasts longer but is less useful or costs a lot more to run) and either type of fluorescent very slowly loses the gas that makes it work.
It doesn't help that the old Edison screw is terrible for cooling.
But it's still a perfectly good counter to "no sane option".
Unless there's some regulatorially-mandated set of minimum standards, given the thin information channel of price ("what will I have to pay out of pocket right now for Product X, with no other indicator of quality, longevity, or potential risks"), the market will pursue low costs with an iron determination, over all other factors.
Consider that a corrolary of Gresham's Law, which in its essence says that given a nominal currency value, currency of lower determinable quality (lower specie metal content) will tend to drive higher-quality currency from the market.
"But wait, Dred," you say, "You just said that there was no other indicator of value. Why is low specie currency driving out high specie?"
Because that's not the relevant value, and it actually is apparent (or at least sufficiently so to a certain number of traders in coin). It's the nominal value that's the determinant for circulation. In the case of coin, it's face value which determines market exchange. Put another way: in a world of copper-painted zinc lozenges circulating as pennies, a diamond-encrusted gold penny will still only net you $0.01 in exchange value as currency. You're better off holding on to it or trading it for its specie / gem value.
With bulbs or electronics, the logic shifts around a bit, but the result is similar. Price becomes exchange value, product quality factors (colour registration, colour range, flicker rate, dimmer compatibility and performance, heat dissipation, any electronics buzz or hum, diffusion pattern, and most of all, that one factor you cannot determine in 3-5 minutes at a store: product life (or more properly: product-quality-life, the period of time it functions adequately before driving you bananas, even if it doesn't fully fail).
You're standing in a store aisle, or staring at an utterly uninformative webpage of quite probably counterfeit and fake-reviewed Amazon LED bulbs as well as whatever LED-bulb-adjacent search results Amazon's Alexa Search Engine has decided it needs to distract you with today, and you see two things:
- LED bulb.
- Price.
And "you" is the typical shopper. Which is to say, one who's not read this particular screed.
What are you going to do?
You're going to pick the lowest-cost bulb you see and offer a prayer to His Noodliness.
This is, incidentally, a chief reason why pure market solutions tend toward abysmal product offerings in the absence of some external regulatory, ratings, or similar systems.
There's an alternative, and some retailers follow this. Marks & Spencer in the UK long made a tradition of carrying only one exemplar of a brand, generally represented as "the best there is". That is, M&S undertake the research and quality determination costs for its customers. Your research problem is reduced to "shop M&S".
In the US there are retailers who follow a similar strategy, though emphasizing the price-quality relationship. Costco is among these, where typically only a small range of products within a category is offered (Trader Joe's operates similarly, though only in food). Friends purchased a convection toaster-oven from Costco recently -- not the cheapest model out there, but one which performs quite admirably, will handle a frozen pizza and most meals for 2-3 quite well, and (whilst slightly tricked out on controls) is fairly simple and straightforward to operate. On balance, "shop Costco" has been justified in this case.
The pure-pricing model typically works best (if at all) for nondifferentiable commodities of minimum complexity. Foodstuffs, bulk construction materials such as sand and gravel, coal, oil, etc. And yet even within each of these in developed economies you'll find grading and quality control, some imposed by government mandates, some self-adopted by industry.
And outside of bulk commodities -- in services, in wages, in rents, in interest and risk markets, in public goods -- pure market-based pricing absent various corrections, breaks down entirely or leads inevitably to pathological conditions. See "Iron Law of Wages" and "Law of Rent" -- the twin prods of numerous revolutions.
The problem with your "sane option" is that at mass market scale, say, the 100 million or so households in the US, or the 300 millions or so in China, it simply does not scale. Information and expertise implies some level of clustering and trust relations. Commodity pricing doesn't provide for this.
Yes, but what is a "pure market"? I like to believe that my local home improvement or grocery store has some kind of concept of their own brand and puts some effort into getting decent products on the shelf, whether store brand or not. So, I hope that their markets are not as "pure" as online sites where anyone can sell.
In the case of a brick-and-mortar store, part of what the retailer is paying is for a physical retail location, which you might think of as access to a specific cohort of local traffic (foot, vehicle), and customers, in the sense of patronage of a retail establishment by custom (https://www.etymonline.com/word/customer).
Since that is a finite set, and there are often (though not always) competing retailers, practices which alienate customers tend to be counterproductive.
I was actually thinking of the local B&M hardware store where the staff know their products, and customers, and I've been making a series of (to date, satisfactory) LED bulb purchases whilst writing my earlier comment. What is ultimately carried is a function of the store's specific traffic, the parent corporation, and other arrangements (there are periodic government and utility incentives for low-energy bulbs), but the local staff and management have some agency.
Existential Comics' "Freedom Monster" thought experiment is worth consideration:
I think it's an oversight to mention bulk commodities as an exception to the need for quality information. Things are bulk commodities because there are standards and regulations that enable them to be traded easily.
"Bulk commodity" in trade means that a good is comprised of units (discrete or continuous) of equally-interchangeable quality, as opposed to a good which is comprised entirely of unique entities.
If I take a brick, or a shovelful of sand, or a barrel of rainwater, a ton of iron, a bushel of wheat, a dollar or yen or pound from you, and return another to you later, it doesn't matter if you get back the same unit or a different one, so long as the quality is equivalent.
If I take a Monet or Picasso or first-edition Gutenberg Bible or the Hope Diamond, you're going to want that specific item back, not a replica, no matter how exact or precise.
If I order a package of washing-up liquid from Amazon and that goes walkabout, Amazon can simply ship another unit of soap and I'll be happy.
If I order a pair of prescription eyeglasses and those go walkabout, Amazon cannot simply redirect another customer's order to me -- the specific nature of the glasses -- prescription, frame choice, fit, lens coatings -- matter.
Bulk commodities are highly undifferentiated. Within a commodity class, they're infinitely substitutable. Once a price is determined, what you get for that price really doesn't much matter. In other words, it's the realm of market-based exchange most amenable to price-as-the-only-signal you can find.
And yet, it still doesn't rely on price-as-the-only-signal.
Even amongst commodities, there are quality measures. You want your sand to be sand, not dirt or plastic. For specific applications, river rather than beach sand. Grain is controlled for moisture content, spoilage, and insect fragments. There are quality standards imposed by mechanisms other than price.
Your (apparent) objection to my comment was actually the point I was trying to make.
But thank you.
E.g. I get relatively good bulbs by requiring CRI > 90. Or just requiring no flicker, as a feature. When the producer has more than one parameter to optimize, they seem to come up with more well-rounded designs. To say nothing of the useful features I mentioned.
Yes, I likely pay 2-4 times more for these bulbs. But they perform, and they stay for years of intense use. The cheapest overall bulbs are designed for other purposes.
Philips is selling its small domestic appliances business and hoping to strike a similar deal regarding the licensed use of the name Philips. They are centering solely around the Health business now.
I've put in some "filament" style LEDs, these look like they will last longer as there doesn't appear to be a power supply taking up half the bulb (although there are electronics down in the screw part).
Also, I see many people getting extremely bright bulbs and putting a large fully opaque light shade over them. That’s rather counter productive.
There apparently are 200,000 hour L70 fixtures [2], but I haven't found any 250K, 300K, 400K, or 500K hour units.
If we ignored form for pure functionality to get the full-rated life of the bulbs, I wonder what the design/specs would look like. The longest DC power supply I could quickly find a mention of is an Antec line, so I wonder what a really long-lived (50-100 year) DC power supply design would look like.
[1] https://www.accessfixtures.com/led-lifetime-l70/
[2] https://www.google.com/search?client=safari&rls=en&q=200000+...
Philips bulbs seem to do much better in the ceiling. If only they'd make 3000k bulbs...
There's a bedside lamp next to the bed and the bulb is at least 30 years old. Two generation of children have used that bedside lamp to read stuff at night or walk to the bathroom.
Meanwhile my LED - whatever the brand - are failing between 6 months and two years.
Nonetheless in the last 20 years all my normal light bulbs had to be replaced on a regular schedule which was often enough that i got slightly annnoyed by it.
My expensive philips hue, no issues so far.
18 years now, maybe longer, but it still turns on and has yet to burn out. Of course, we don't use it much, and it's only something like 30 watts (clear bulb).
Someday, maybe, it'll get replaced.
I think it's more about how well balanced all of the individual LED's in the bulb are. Unbalanced circuits have more current flowing through some paths than others and leads to premature failure of individual elements and it's usually rapidly downhill from there for the rest of the bulb.
all at once?
Hopefully you bought a problematic model, and they’re not uniformly going downhill.
How old are the ones that are failing for you?
For CFL, it's a bit more complicated, but keep in mind that they do have quite a bit of glass (takes energy to make and form), need some mercury, and at least as much electronics (if not more) as LEDs. Furthermore CFLs don't necessary fail completely, but degrade over time. Thus they're a bit less efficient than LEDs to begin with, but a lot less after a few years.
So overall, unless the LED is so shitty as to consistently fail within weeks, there's no doubt their total energy bill is competitive, and it's even more clear if you limit the comparison to products of similar quality.
They weren't cheap, but they weren't mega expensive either.
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...
https://thebark.com/content/heres-what-dogs-see-when-they-wa...
Even if that 75Hz number were derived from deep understanding and measurement of the entire visual pathway, there are variations in perception for people, there most likely are for dogs as well.
Perceiving flicker has a higher threshold. I can perceive 60Hz flicker in my peripheral vision easily enough.
Other sources online (you can find lots of them but I didn't see an obvious authoritative article) suggest that 16Hz is the flicker fusion rate for motion in humans.
Flicker fusion for continuous brightness (CFF) is somewhere around 30Hz per https://www.nature.com/articles/s41598-017-15034-z and it rises with brightness - this paper is about testing how it changes in different circumstances.
Most of the reason you don’t is because filmmakers know very well what their “maximum pan speed” is and they stay as far away from it as possible.
1000Hz I find hard to fathom, though. Would want to see what these signals look like.
Classical 50/60Hz lighting looks like a stroboscope to chickens. There is a whole field of research on the effect of light regimes, light color and flicker on poultry farming efficiency. I couldn’t find a scientific link, but see https://agrilight.nl/lichtadvies/pluimvee/?lang=en&-en
Philips' discount brand (Attralux) is even cheaper, I recently bought more of these 8W 800lm for less than €1 a piece. For now I cannot tell the difference.
Sorry...I just noticed you are talking about filament LED and not old fashioned analog filament bulbs.
In the CATV industry, we used to send 110 analog channels across roughly 800MHz of spectrum (54MHz to 860MHz). Other than background and ingress noise, a major source of noise (effectively) was distortion - non-linearities in the amplifiers that kept the signal at a reasonable level. Composite Second Order (CSO) and Composite Triple Beat (CTB) distortions were two values that equipment transporting these signals would generally call out - they are analogous to the summing and differencing of two signals and three signals (respectively) as described above for the lightbulb, but imagine doing that with 110 different frequencies simultaneously.
But for the 'real cheap' bulbs, they likely (due to being "real cheap") have either a half wave or full wave rectifier (i.e., no switching PSU) which results in the LED's having a flicker at power line frequency (either 50hz, 60hz, 100hz, or 120hz depending upon which combination of line frequency and full/half wave rectifier is present).
Imperceptible if you are just looking at it, but in a dark room if you move something quickly in front of it you can see the strobe effect.
Unfortunately, Powerwalls and other similar products are made with built-in inverters and connect only to AC, there is no DC tap. And there aren't any standards around DC wiring and small appliances, so it isn't likely to get traction.
I'm mentioned before (https://news.ycombinator.com/item?id=21109247) that I've seen a DC installation at a friend's house, he used 12V cable lights and DC bulbs, so it seems to work.
Filament LED bulbs (the ones that look almost exactly like clear incandescent bulbs with a visible filament when turned on) do this because they have to fit their electronics in the tiny metal base. Room enough for some diodes (and maybe a capacitor), but usually not a full set of high frequency switching electronics like in most other LED bulbs (although I've seen some filament bulb tear downs that might show more advanced electronics). But again, doesn't bother me due to their high duty cycle and relatively okay refresh rate.
(At least, this is all my impression. Please correct me.)
What does it take to make them not flicker? I.e. how much of a cost increase is required?
Honestly it's starting to feel like a most cost effective long term solution is to build homes with a master AD/DC converter (or several depending on sq/ft) and simply wire 12v outlets and light fixtures. The energy savings of swapping all incandescents or compact florescence bulbs with cheap LEDs with cheaper power converters is starting to scare me knowing just how shoddy and fire prone some of these power converters can be.
The OLED displays in current smartphones also exhibit a visible strobe effect at lower brightness settings. I figured I’d get used to it but ended up returning my iPhone 11 pro after a week because it was driving me nuts. I’ve met a few people who perceive it as well but most seemed to have no idea what I was talking about.
Indeed, to the housefly, an incandescent-bulb-lit house slowly pulses from light to dark, so probably too with cheap line voltage choppers.
This sounds amazing to me, but also confusing. My understanding is that an incandescent bulb works entirely by heating up the filament. There should be no way that the filament is cooling down and heating up in anywhere close to the rate that it would require to get some kind of wagon-wheel effect, which is what it sounds like you're describing.
The varying current through the tungsten will result in a varying power consumption (varying at a 60hz rate). The varying power consumption will result in a small amount of varying temperature on the filament.
Now, the filament does not cool down instantly, so the result is its temperature will vary by a few degrees, but likely not enough to ever be perceptible to human eyes. But with a sensitive enough (and fast reacting enough) temperature probe, one could likely measure the temperature rise/fall of the filament that is synchronized with the line frequency.
I'm not sure you've shown that this would be visible to a housefly as a "slow pulse from light to dark," as the post I was replying to claimed. First of all, you said the power consumption will vary at a 60hz rate, but it seems to me it will vary at a 120hz rate, since the current will be at its max magnitude twice per cycle (as you say in the first paragraph). But more to the point, I don't know whether the temperature/lumens will decrease enough in 1/120th of a second to be visible to houseflies or anything else.
Trying to research the answer, I found this physics lab worksheet [1] from Pasco (the makers of sensors), for a high school lab measuring the output frequency of incandescent bulbs vs fluorescent bulbs, but without doing the lab I don't know the results.
The numbers here show a >25% difference for an example bulb.
Also, even ignoring how the cooling starts off at its fastest, with radiation scaled to the fourth power of temperature... incandescent lights switch off in about a tenth of a second. Even if that was completely linear, it would be very visible. Even a 1% flicker would be visible.
https://www.youtube.com/watch?v=eUprJS9sXYU
https://www.youtube.com/watch?v=jXx5eEzMmYo
It's not an extreme brightness change, but it's possible to do a lot better.
Anecdotally from my experience as a macro photographer, the threshold for flies is lower than for dragonflies; flies often startle in response to movements almost too tiny to perceive having made, while dragonflies are relatively easy, usually requiring only a few minutes to approach from a distance of a meter or so to the ~12cm minimum focus distance of my best macro lens. (It's hard to know; the passage of time isn't of much interest in the focused flow state that's required for this sort of activity.) It helps that disturbed dragonflies tend much more often to return to the same perch, but with some practice it's possible to make the entire approach without disturbing them at all. The only really tricky part about it is that, when you're moving slowly enough, they also tend to land on you, which can be somewhat distracting if you're ticklish.
In any case, the existence of a minimum rate of change for perception of motion suggests that flickering light below a certain frequency might well be perceived as strongly discontinuous.
(It also merits mention that my macro rig includes three very powerful flash heads mounted around the lens front element. I've never observed dragonflies, wasps, bees, flies, or spiders to react to these in any way, even when firing from a distance of six inches; the only reaction I've seen has been from fall webworm caterpillars, which displayed a communal defensive response, and that may have been as much due to the shadow I cast, or to the polistid wasps hunting nearby, as to my flashes firing. The wasps notably did not care at all about me or my flashes, especially after they also found the nest and busied themselves with its rapid depopulation.)
The best flicker-free lights are ones that have low ripple constant current power supplies (somewhat expensive). LED lamps intended for use around rotating machinery used to all be this way until someone figured out that if the PWM frequency was wildly unstable it would prevent the problems with strobe lights around spinning things at a fraction of the cost.
Let say it is called CLED,
And it requires the following features / spec before it could be called CLED. From PWM, Colour Correctness, Energy Efficiency, heat etc. The different between a low price light bulb and higher priced is relatively minimal , the difference in LEDs is massive. To be point they should not even be allowed into the market in the first place.
Are all these cheap SMPS driving our pets insane? (or just annoying them? or neither?)
I wonder if I could rent some super-high-quality mic from a local sound reinforcement studio and look at a 20-60kHz FFT ... or do fancy mics not really go beyond human hearing?
Just white. We run whatever cheap bulbs in my house at the moment, but also tend to do to a lot of "slow mo" videos and it kills me every time.
I'd prefer NOT to spend $15+ a bulb for crazy high end but would be more fine with say, $5+ a bulb
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.
The sun gets up to 1.6 billion candela per meter squared. 850 lumens in a 120 degree cone, from a 5x5mm surface, is about 11 million candela per square meter if I did the math right. With a retinal danger level around 100 million, you'd need some very strong secondary effects to damage yourself with an 11 million source.
Secondary effects like boiling your entire eyeball, or overloading the cornea while the retina is safe. And I don't have the knowledge here to say if that happens, or if your body can easily sink a spread-out watt of light and nothing bad happens.
Normal retinal spot burns are not about total light coming into your eye. They're about incoming light per solid angle. A light that is bright enough per area is dangerous at any distance, until it's so so far away it looks like a single point.
I'm sure that there's some level at which total light is damaging, even if there are no super bright spots. But that level is going to be significantly higher than 120k. It's maybe a range this LED can reach, maybe not.
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.
And that's not one brand. I have GE bulbs, Philips (Hue and not), and random brands from Amazon.
(Anyone know how good Austin Energy's electricity on the west side is?)
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.
I monitor the electric service at my house and it's very steady at 240V.
Also tulip like lamp shades where the base is at the top can concentrate heat and wear the electronics down; canister mounts do the same if no venting.
Lowe's is stocking GE these days, but I'm not familiar with their quality. The reason I'm not familiar is that they exclusively stocked Feit initially, and yes, those things are pure garbage. They had high failure rates and were not "instant on" compared to others. I stopped buying them and switched over to the Home Depot brand.
There are a few other brands you can get online that have better rendering (CRI), and are more accurate to the stated color temperature over time, but they cost sometimes double what even the Philips bulbs cost.
I also wanted to add a data point that I've switched every light in our house to LEDs over the past decade, and only had two bulbs (out of maybe 50+) fail in that time—both were in outdoor fixtures which range from 10-100% humidity, and -10°F to 110°F through the year (quite a torture test).
You just can’t win.
In the variety of old bulbs, the Feit ones in particular were causing issues with dimmers and also getting slightly discolored and buzzy. Only one had outright died, but seemed that more were on their way.
All the new GE ones have been great so far (only a year), but I'll let you know in 10 more years.
Refreshing all the lighting in the house with modern, matching, actual-dimmable LED bulbs (along with nice dimmer switches) has been a really nice ambiance upgrade.
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.
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?
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.
Neutral does not go through the breaker, correct.
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.
> Even I have trouble understanding the real difference between ground and neutral,
Neutral is the normal return path for current. Under normal operation power is delivered to a device via the "hot" conductor, and travels back from the device to the source over the neutral conductor.
The ground conductor is present for safety purposes. Under normal operation no current should flow over the ground conductor at all. The only time the ground should have a current flow is during a safety event (i.e. a short from hot to the case of a device with a metal case).
> I'm not even sure if neutral goes through the breaker?
It does not, the breaker is present in the "hot" conductor path, and tripping the breaker disconnects just the hot conductor from the power source.
[1] https://led-driver.power.com/products/product-archive/linksw...
Or are there other considerations that mean non-electrolytic capacitors are unsuitable?
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.
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-n...
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.)
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.
https://www.youtube.com/watch?v=osauwVoP4a8
https://www.youtube.com/watch?v=-ZPo7C3PDT4
I also highly recommend the Smart Home Solver YouTube channel if you're interested in home automation
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.
Hence I would not hesitate to give their smart bulbs a try as well, assuming they use the same circuitry and LEDs for the "non-smarts" of the bulbs as for all the others.
Also, for a smart bulb I find their control requirements to be weird. Pair with this device first, but only up to X devices, then pair that with the hub. Everything else I have is Z-wave so maybe this is par for the course for smart bulbs and I'm just not used to it.
[1] https://www.reddit.com/r/tradfri/comments/bddyjt/connect_tr%...
[2] https://www.reddit.com/r/tradfri/comments/aq0161/pairing_wit...
Evilgenius has a level shifting board for the ESP32 or ESP8266 that takes a lot of the hassle out if you need many separate patterns.
They operate on 2.4ghz wifi and after inspecting the traffic do not appear to be funneling my data to China.
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).
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?
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
If there was anything to be gained from doing it that way, it would already be done in commercial build outs.
Should cheaply provide better heat dissipation than air, no?
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.