Well, today I learned to install one capacitor in reverse orientation on the PCB on a 34 year old computer...
Definitely starting Wednesday off productively.
Well, until today I didn't even know capacitor can have orientation! So more productive Wednesday than yours. In entry level electronics class I had decades ago it was always treated as a component that works the same way no matter in which direction the current flows.
Ceramic capacitors don't have polarity. Electrolytic ones do. Thing is, electrolytic capacitors have far higher capacitance for their size -- though also higher resistance.
It's something to check, but the polar ones should be clearly marked as such.
Electrolytic capacitors are kinda like lead-acid batteries in that they are polarized through manufacturing processes. A voltage is applied in the factory to anodize the anode with a thin oxide layer. For fun, I think it would be possible to buy a quality low voltage cap and reverse the polarity of it in-situ which would remove the anodization from the new cathode and deposit a new layer on the new anode (former cathode) hopefully without over-pressurizing it to bursting, albeit with much less anticipated lifespan.
PSA: Electrolytic capacitors have a rough lifespan of 10 years. Any much older than that need to be checked out-of-circuit for ESR and then capacitance. Also, tantalums (historically) suck(ed). [0] Quality audio equipment from the 80's like a/d/s/ car amps used only ceramic caps and other over-engineered passives, and have the potential (pun intended) to basically last forever.
0. https://www.eevblog.com/forum/projects/whenwhy-(not)-to-use-...
Or much shorter, around two years, if it was part of the Capacitor Plague.
https://en.wikipedia.org/wiki/Capacitor_plague#Premature_fai...
The normal lifespan of a non-solid electrolytic capacitor of consumer quality, typically rated at 2000 h/85 °C and operating at 40 °C, is roughly 6 years. It can be more than 10 years for a 1000 h/105 °C capacitor operating at 40 °C. Electrolytic capacitors that operate at a lower temperature can have a considerably longer lifespan. ... The life of an electrolytic capacitor with defective electrolyte can be as little as two years.This is also why so many LED bulbs are shit, lots of heat in a small space full of electrolytic caps.
Recently read that if you are going to be using an LED bulb in an enclosed space, buy bulbs designed for the high temperature, otherwise you WILL get premature failures in bulbs that will last for years in ordinary lamps.
https://duckduckgo.com/?t=lm&q=led+bulbs+enclosed+fixture+ra...
Alternatively, there are now much more efficient bulbs available. If they're passing A under the new EU Energy Label (from 2021) they'll barely be warm to the touch.
Intentional planned consumption/obsolescence by design. This class of problem is where under-regulation and lack of standards benefits only sellers and cheats buyers. PS: Also, Amazon should be required to test all of the electronic, safety, and food products on its site such that they can prove safety and standards conformance.
I am assuming you are an ee (like myself)...I have never designed a product with a built in expiration, nor have I ever seen any app notes or write ups on the engineering of it - something engineers love to do.
What I have seen done is cheaping out on parts in order to get the price as low as possible, because customers shop primarily on price.
Not to lash out, but it kind of hits a nerve for me, because people think we design products to purposely fail. Hell no, we try really hard to do the opposite, but everyone just loves to buy the cheapest shit.
The $25 LED bulb that will last for eternity will rot on the shelf next to the $3 bulb that will probably be dead in 6 months. And one more "they build these things to fail" complaint will be posted online.
To be fair this is hardly limited to EE and is the issue with the race to the bottom in all product categories. Make long-lasting high-quality 100$ pants? People prefer spending 10$ on Shein.
Additionally, the issue is that as a consumer, it's not easy to differentiate between quality markup and greedy markup. I don't see the cap manufacturer on the box so the 25$ light bulb might last 10 years or it might last 6 months just like the 3$ one. At least with the 3$ one I can come back and buy another...
I agree with what you said - engineers do the best they can with the budget but the budget is small because people won’t pay for things that last - but it’s worth saying that any boards with electrolytic capacitors have an inherent built in expiration. Any product with rubber has an expiration. Any product with permanent batteries, glued or sealed assemblies, or no spare parts. Much of that is with the customer’s budget, sure. But these days, even among expensive things, nearly nothing is built to last.
Not LED light bulbs specifically, but...
"The Phoebus cartel engineered a shorter-lived lightbulb and gave birth to planned obsolescence"
It's true that the Phoebus cartel arranged to have light bulbs die after a certain number of hours, but bulb lifetime is a trade off between lumens, filament life, and energy consumption. The cartel-defined lifetime limit sits very close to the sweet spot for all of those metrics for incandescent bulbs.
Technology Connections explained this well in a video about a year ago: https://youtu.be/zb7Bs98KmnY
I seriously doubt it's ever a deliberate conspiracy in engineering apart from shenanigans like what happened at VW, but it's net effect of product managers, accountants, and contract manufacturers who modify PCBs and BOMs after it's passed off to them to save money on retail products. And so it's likely unintentional with negligence, but it benefits the company. Except for some Samsung appliances made ~ 2010-2014 which seemed to fail just after their warranties expired. I suspect highly-optimized designs for "consumables" like incandescent lightbulbs and parts for cars use data to tweak design life, more often than not, in their favor. And, with the pressures of multinational oligopolies and BlackRock/Vanguard/State Street.. there is little incentive to invest $100M into a moderately-superior incandescent lightbulb using yesterday's technology that lasts 100kh and 5k cycles and sells for $1 more than the next one. Maybe if we (perhaps a science/engineering nonprofit thinktank that spanned the world and gave away designs and manufacturing expertise) had quasi-communism for R&D, we could have very nice things.
It's not my fault if other people are too dumb to comprehend TCO because I would buy the $25 bulb if it had a 30 year warranty.
> Except for some Samsung appliances made ~ 2010-2014 which seemed to fail just after their warranties expired.
And? That just sounds like they have good engineers. If you are designing a machine, you have an target lifetime. You'd obviously want the product to last through the warranty period, because warranty claims are a cost to the company.
Every choice of a component affects lifetime. Designers of mass-market products can't just use premium components everywhere -- the mass market will not pay steep premiums for otherwise equivalent products.
Value engineering and planned obsolescence are not the same thing, but they are often confused.
That being said, Samsung appliances suck and I hate them. Mine failed within warranty several times.
> And, with the pressures of multinational oligopolies and BlackRock/Vanguard/State Street.. there is little incentive to invest $100M into a moderately-superior incandescent lightbulb using yesterday's technology that lasts 100kh and 5k cycles and sells for $1 more than the next one.
It isn't that. It's pressure at the shelf that does it. Consumers behavior simply does not reward equivalent-feature products with premium components that claim (true or not) to have a longer lifespan. Unfortunately, they will buy based on their uninformed sense of quality first.
If you release a light bulb that is identical to the best selling one on the shelf, but claims 10x lifespan, your competitor will do something like gluing a weight in theirs, putting some marketing BS on the box, and will put you out of business. Consumers just don't pick products based on actual quality.
> And? That just sounds like they have good engineers. If you are designing a machine, you have an target lifetime. You'd obviously want the product to last through the warranty period, because warranty claims are a cost to the company.
> Every choice of a component affects lifetime. Designers of mass-market products can't just use premium components everywhere -- the mass market will not pay steep premiums for otherwise equivalent products.
Dying just out of warranty is only okay if the warranty covers the actual expected lifetime of the product. And for appliances, it doesn't.
The difference between a 5 year washing machine and a 30 year washing machine is not very big. Anyone pinching those specific pennies is doing a bad thing.
You're making a pretty awkward value judgement about what a "good" engineer is, but you're describing an unethical one with a bizword like "value engineering". I realize ethics are no longer understood by much of Western society because the culture teaches transactionality, worships trickle-down economics and greed, and hyperindividualism.
> It isn't that. It's pressure at the shelf that does it. Consumers behavior simply does not reward equivalent-feature products with premium components that claim (true or not) to have a longer lifespan. Unfortunately, they will buy based on their uninformed sense of quality first.
This is a failure of marketing and buzz of the sales channel(s) and manufacturers to educate properly, not the failure of the customer.
A good engineer is one that has a job, doesn't put their employer out of business, and produces work that fulfills the requirements they're given.
Many people think there's some unethical conspiracy going on, and consumers actually want a product that lasts a long time, but companies are refusing to give it to them. But this is projection of individual preferences on to the market as a whole. Consumers want cheap shit that is in fashion, and their buying preferences prove this time and again. Maybe you want a 50 year old toaster in your kitchen, other people are buying products based on other factors.
If consumers really wanted to pay a premium for high duty-cycle equipment with premium lifespans, they can already do that by buying commercial grade equipment. But they don't.
If you are familiar with the history of home appliances, you'd probably come to appreciate the phrase 'value engineering'. Even poor people can afford basic electric appliances now because of the ingenuous ways that engineers have designed surprisingly usable appliances out of very minimal and efficient designs.
If you look at ads for electric toasters 100 years ago, you'd see they cost over $300 in today's money adjusted for inflation. Thank god for value engineering.
A good engineer provides value to society. If they fulfill requirements that are bad for others then they are not good engineers.
I seems to me that there is also a social dynamic to things. If consumer grade products become a race to the bottom then it is going to become more difficult for regular people to purchase products which aren't low quality. There's also a degree to which society (e.g. in the form of government policy, cost of living adjustments, etc.) factors in differences in prices.
The fact that poor people can now afford to own some household appliances isn't a huge value to society?
It completely changed the way our societies operate. I think it is a good thing that people have the option to buy crappy washing machines, rather than being forced to use the washboard and bucket my grandmother used. Yeah, they sometimes do develop a bad belt, or the timer mechanism might fail. But it beats being unwillingly forced into homemaking as a career.
The world only has so much wealth to go around, and that isn't the moral quandary of the engineer picking an item on a BOM on Tuesday morning to fix. If anything, squeezing a few more pennies out of that BOM is going to lift some people at the fringes out of poverty. At the opposite end of the product value equation, every unused and functional component in every product that is no longer in service, is wealth that is wasted that could have been spent elsewhere.
Engineers are to consider public safety first. This is not negotiable for real hardware engineering. Poor people could always purchase used appliances.
I agree that products shouldn't be unsafe. And value engineering does not mean making products unsafe.
> Poor people could always purchase used appliances.
The reality in mid 20th century US demonstrates this isn't the case. Most went without the modern appliances that are commonplace today.
> Intentional planned consumption/obsolescence
No it isn't. It is simply optimization of price and the features/form-factor that many buyers have demanded.
If anything, the lifespan of a ~$1.50 household LED bulb is quite incredible. I'm not sure exactly how anyone would be able to increase the lifespan at that price point and keep the traditional Edison form factor.
> Amazon should be required to test all [..] products on its site such that they can prove safety and standards conformance.
No, the manufacturers should be required to... the same way it works for literally every other product with safety regulations.
> If anything, the lifespan of a ~$1.50 household LED bulb is quite incredible. I'm not sure exactly how anyone would be able to increase the lifespan at that price point and keep the traditional Edison form factor.
I don't think I've had any last more than 5 years.
If you bought a cutting edge LED bulb back in 2002 or so, those had a life expectancy of over 60 years, and the build quality was such that you could reasonably expect to get that.
There are plenty of teardowns on YT showing how poorly even major brand name LED bulbs are put together.
Yeah I would hope those bulbs were built pretty well, they were crazy expensive... expensive enough that they wouldn't be competitive in lifetime-per-dollar against today's crappiest bulbs even if they lasted a person's entire lifetime.
> I don't think I've had any last more than 5 years.
Do you shut them off every 3 hours? That's probably what the estimate on the box is based on. Run the same bulb half the day and you'll only get 2.5 years out of it.
> There are plenty of teardowns on YT showing how poorly even major brand name LED bulbs are put together.
I've seen them. And dissected my own. Still, at the price that modern LED bulbs are being made, I'm surprised they're built as well as they are. Brand name Sylvania bulbs are $0.79/ea in a bulk Amazon right now.
> I've seen them. And dissected my own. Still, at the price that modern LED bulbs are being made, I'm surprised they're built as well as they are. Brand name Sylvania bulbs are $0.79/ea in a bulk Amazon right now.
LED bulbs aren't lasting any longer than incandescent bulbs used to. My house has 2 bathrooms, one had incandescent bulbs when I moved in and I didn't bother to replace them. Those incandescent bulbs have outlived multiple sets of LED bulbs in the other bathroom.
I honestly worry about the increase in e-waste with LED bulbs vs the old incandescent bulbs.
> Do you shut them off every 3 hours? That's probably what the estimate on the box is based on. Run the same bulb half the day and you'll only get 2.5 years out of it.
Which given that LEDs should damn well last 20-30 years of always being on, this is all a farce. I can't even pay 2x the price to buy a bulb with an honestly stated lifetime on it.
> Yeah I would hope those bulbs were built pretty well, they were crazy expensive... expensive enough that they wouldn't be competitive in lifetime-per-dollar against today's crappiest bulbs even if they lasted a person's entire lifetime.
I bet they would be. Given LED bulbs last less than 3 years now, with some not even lasting 2 years, a 20-30 year bulb could cost 4x as much and be competitive.
The real problem is that those long lifetime LED bulbs are not driven as hard, so the light output isn't nearly as high. AFAIK all research in the last 20 years has been into bright LEDs with meh lifetimes, so I wonder if it is even possible to mass produce long lifetime consumer LEDs anymore.
(Except the LEDs in all my consumer electronics have no problems staying on for 5 years non-stop! Tiny output, long lifespan...)
The problem is that the manufacturers lie and say that the LED bulbs will last for many years when they don't.
The claim they put on the box is typically true, but based on some damn modest usage. (e.g. 3 hours per day in ideal environmental conditions) And of course, a mean-time-to-failure figure to someone with one bulb built with minimal QA is just a dice-roll when faced with the bathtub curve of product failures.
That, and customers insisting on preexisting form factors. Fitting the electronics and LEDs into the space of a traditional lightbulb comes with compromises, such as not having proper heat dissipation on either.
Please think for a moment not only about whether it's feasible for AMZN to run a safety testing program for all possible consumer products of our modern technological civilization, but whether you really want them to be in charge of it. Maybe they should just require certifications of testing in the jurisdictions where those products are sold?
Isn't faking certs already a problem?
Probably. Is it a worse problem than Amazon inspecting themselves would be? Is it a worse problem than Amazon demonstrably already has with policing counterfeits? I'm just saying, you could hardly ask for a less-qualified authority for product testing. At least with independent certs it's vaguely possible to align the incentives correctly. With Amazon the incentives would be hosed from the start.
Here's a question for EE nerds that happen to be reading this (maybe in the future).
What if I have a stash of big electrolytics that have been out of service for 10+ years? I know that I need to reform them over a few days, but can they even run at spec after so long out of operation?
We're talking BIG stuff, 400v, 200+J each
> Any much older than that need to be checked out-of-circuit for ESR and then capacitance
And that's a very time consuming and somewhat risky operation on an old machine you want to keep running. Some old PCBs are quite fragile.
I wish there was a way to test capacitors without removing them.
You can test ESR in-circuit, with caveats. Here's a good thread from EEVblog [1].
[1] https://www.eevblog.com/forum/beginners/is-there-any-way-to-...
Bipolar electrolytic capacitors are a thing, I recently had to solder up a handful of them in some audio circuits.
Once you have experienced blowing up a reversed elcap you will never forget its orientation. I never understood though what makes it leak current and hence heat up.
Modern electrolytic caps don't burn like they used to.
The last few times I made a mistake, there wasn't even an explosion, even less a short-circuit. The thing slowly boiled and bubbled or unfolded.
Anyway, it blows up because the capacitor's insulation layer isn't some stable material, it's a tiny oxide layer built over the metal plate by anodization. If you put a high voltage on it with the wrong polarity, you reverse that anodization and short the liquid and the metal electrodes.
There's an aluminum oxide layer as a coating on both the anode and cathode inside the (electrolytic) capacitor. Under forward voltage it will gradually thicken but under reverse voltage it dissolves and causes a short. This increases the temperature which causes hydrogen ions to separate and bubble through the material, increasing pressure within the capacitor package until it bursts.
There are polarised and unpolarised capacitors. Stuff like basic decoupling capacitors tend to be unpolarised.
I actually have an LC III in storage, so I might actually be able to make use of this article.
I think this will allow me to classify today as productive.
Yeah, I have a Performa 450, which I believe is the exact same computer sold under a different name. So this is definitely important to know. I can go back to bed now, my job for today is done.