
Teardown of a $1.25 LED Lightbulb - teucris
https://electronupdate.blogspot.com/2019/12/dollar-store-led-bulb.html?m=1
======
petercooper
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)
)

~~~
teh_klev
One of my favourite Big Clive moments was when he turned up on Barry Lewis's
channel (a thoroughly nice and decent British amateur cook and kitchen gadget
tester) when Barry had plugged a 120v rated grilled cheese toaster into a UK
240v household supply, near kitchen conflagration hilarity ensues:

Video:

[https://www.youtube.com/watch?v=H66Fbg9nrk4](https://www.youtube.com/watch?v=H66Fbg9nrk4)

Clive's comment:

[https://www.youtube.com/watch?v=H66Fbg9nrk4&lc=UgyLpu-
CcVthk...](https://www.youtube.com/watch?v=H66Fbg9nrk4&lc=UgyLpu-
CcVthkaYcsgR4AaABAg)

 _" 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.

------
lgleason
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.

~~~
johnchristopher
I am reading this post on my laptop, in bed. In my grand parent's house.

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.

edit: [https://imgur.com/c6B71B4](https://imgur.com/c6B71B4)

~~~
zippergz
Somwething seems wrong if your non-cheap LEDs are dying that quickly. I have
an entire house of LEDs, many going on 5-6 years old, and I only ever recall
replacing two (and they were a pair, used outdoors -- only one failed, but I
replaced both so they would match).

~~~
perl4ever
If you have 5-6 year old LED bulbs, then they represent the state of the
market 5-6 years ago, and aren't necessarily representative of current
quality.

------
spookthesunset
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...

~~~
derefr
It’s not like these bulbs are flickering in a way you can perceive _just_ by
slowing it down by 2/3/4x. They’re flickering at 10000+ Hz. The reason cameras
perceive the flicker is that they take discrete samples, with an (electronic
or optical) shutter in between. This creates a _beat frequency_ with things
that also flicker, in effect “tuning into” a HF flicker and “lowering it” into
the visible range, the same way a superheterodyne radio tunes into a HF
carrier wave and brings it down into the audible range.

~~~
pwg
The 10khz+ flicker only comes about if the bulbs have a proper switching power
supply (and if that switching power supply itself runs at 10khz+).

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).

~~~
nicolaslem
Now that incandescent bulbs are almost gone, I wonder if it will become common
to have wires carrying DC in the ceiling instead of every bulb having to
implement the AC to DC conversion as cheaply as possible.

~~~
zaroth
I have DC powered under-cabinet lights which are definitely flickering at some
fairly high rate.

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.

~~~
205guy
But where is the DC coming from? If it is a cheap power source (a rectifier
plugged or wired into AC), the DC into the lights could be intermittent, and
so cause flicker. For true continuous DC, you need a good rectifier or get the
current directly from batteries.

------
ThePhysicist
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.

~~~
Dylan16807
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
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.

~~~
Dylan16807
I just don't think illuminance is the most important number here. Luminance is
more relevant to eye damage in the vast majority of cases, because that
measures the spot intensity on your retina. After all, the sun's light would
be completely harmless to the eye if spread over a five degree circle, despite
having exactly the same illuminance. (Well, you would want a UV filter, but
the brightness would be completely neutered.)

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.

~~~
ThePhysicist
I don't think that's right. If I hold this LED right in front of my eye the
retina will be exposed to the entire 850 Lumen. Sunlight with an illuminance
of 120.000 Lux on the other hand yields around 12 Lumen on the retina,
assuming a surface of 1 cm². It's the relative distance to the light source
that makes this so dangerous.

~~~
Dylan16807
Even if you only let a pinhole of sunlight in, enough to illuminate a surface
to 120 instead of 120k, it will burn your retina.

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.

------
jaclaz
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)

------
JoshGlazebrook
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
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.

~~~
JoshGlazebrook
This is at two separate apartments, and a standlone house. All of them seem to
die.

~~~
amiantos
Gotta check your attitude, maybe it's disrupting the DeKalbs. (Sorry for the
Heinlein reference, it was too tempting.)

------
indiantinker
$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
at $0.60, it probably pays for itself in a few months... (energy costs)

------
baybal2
> 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.

~~~
tinus_hn
Anyway European Schuko plugs are not even polarized, there is no way to know
which wire is hot.

~~~
gwbas1c
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?

~~~
pwg
Note, the below will be for the US -- rules will be different in other
countries.

> 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.

~~~
BlueTemplar
Power flows opposite current, doesn't it?

~~~
pwg
I've never heard of that description in all my years as an EE. Do you have a
citation or reference to that description?

~~~
sunstone
Power = I^2*R so power is positive regardless of which way the current is
flowing. (rms current in the case AC, not accounting for power factor)

~~~
BlueTemplar
Right, power can be extracted from flow of electrons/holes, regardless of the
direction...

------
kawfey
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
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...

------
Animats
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/linksw...](https://led-driver.power.com/products/product-
archive/linkswitch-pl/)

~~~
philipkglass
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
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
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.

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

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

------
gwbas1c
> 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
No, it is not a fuse. It is most likely there to limit the inrush current into
the cap when the power is applied.

------
ericol
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.

------
burgerquizz
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?

~~~
Klathmon
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
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.

------
scargill
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
I don't understand these direct AC drivers:

[https://www.electronicsweekly.com/news/why-not-direct-ac-
dri...](https://www.electronicsweekly.com/news/why-not-direct-ac-drive-your-
led-string-2016-04/)

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?

------
Zod666
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.

------
anonsivalley652
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.

------
Zak
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
Do you see new lighting wiring standards emerging anywhere right now? Are they
gaining traction?

~~~
tialaramex
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.

------
fyfy18
> 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.

------
basicplus2
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
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
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.

------
m0zg
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?

------
sjg007
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
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
Why is PoE so popular then?

~~~
samatman
> _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.

------
Scoundreller
So what’s a solution? Bulbs filled with a non-conducting non-flammable liquid?

Should cheaply provide better heat dissipation than air, no?

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

~~~
msisk6
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)

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

~~~
Someone1234
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.

