The standard circuit involves a fuse, a fast Zener clamp, and sometimes a small resistor (e.g. 1 ohm) and/or capacitor. The design parameter is that, with the current limit from the resistor, the Zener should not blow out before the fuse.
The resistor needs to be small enough to not lose a lot of voltage under normal operations, but to still protect the Zener during the short surge during which the fuse blows. For most microelectronics, that's not hard. A 0.5W USB device might have 100mA of current max, which across 1 ohm is 100mV, so negligible for most purposes.
With high-power devices, it gets more complex.
Of course, consumer devices (a) will never be fixed (b) don't sell on this (c) every penny counts, so there's no market pressure to do things right.
But that's how we used to do it, and how it's still done many places where things count. If I'm building a one-off or few-off, it definitely will have proper protection.
That's a good design for input overvoltage protection (assuming I've drawn the correct schematic in my head). But it doesn't help against most other fault conditions, particularly anything to do with the load/downstream going short.
Really, if you care beyond "blow the fuse if something shorts", you need active current limiting. For common cases like USB ports, you can buy chips that do it cheaply and efficiently. There are also some textbook circuits, though they each have their pros and cons. No matter what, if you've got a pass transistor or switching transistor that's about to go seriously overcurrent, you have to do something about it with active parts -- fuses aren't going to get it done.
But defense in depth is always a good strategy, and fuses play a key role there. The active circuitry saves the rest of the design; if it can't get the job done, the fuse makes sure nothing burns.
Yeah, fuses are more of a overload protection kind of stuff. For cases where the load is trying to kill itself and you with it you need current limitation circuits, either on a converter or a latch current limiter.
Orrr you can design your circuit to survive a short condition for a bit longer than a fuse takes to blow. For old cars this was common, let whatever is short take all the current it wants for a tenth of a second and forget about it.the battery may lose a bit of useful life but those things were gonna fail early either way.
Just want to mention how much I appreciate this discussion and the opportunity to learn from it. This is what I come to HN for (nowadays there are also really interesting YouTubers who do informative teardowns of power electronics and other devices, too e.g. Labo de Michel, Watch Wes Work, etc.)
When I used it a decade ago, virtually everything in mercurial was slightly better-designed, more user-friendly, and more polished. Much shorter learning curve.
We've had a lot of change in the past hundred years, and we've reached a point where we can clothe, feed, and house everyone in the world. Once that's done, moving forward more thoughtfully makes a lot of sense.
Who cares if we reach Mars in 2100 or 2200?
On the other hand, I care a lot about avoiding the nuclear / bio / chemical / environmental / and now AI apocalypse.
“we”? i think it’s damn obvious that it’s not “we”. the world doesn’t get to move together until all differences are resolved, is that the progress you think we’ve made in the last 100 years? I don’t understand how talk like this goes unchallenged so often. it’s fine aspirationally but come on! I look at a growing economy like a bicycle, the slower it goes the less stable it is. in other words, you can’t just stop unless you want mass death or you want to transition to a stabilizing mechanism the world is yet unaware of. I would also suggest we don’t foolishly bully human nature with policy- there is a certain and deep injustice to that.
Life’s motto is to grow. asking it to not grow or to greatly hamper it? its outrageous really, especially without a genius respectable path to get there.
i don’t mind aspiration because dreaming is good but this one is a bit tired and uncontested.
and just so i’m not just complaining, i’ll suggest that people stop trying to be dubious global citizens in problem space that outstrips their capabilities and work to be better stewards of one’s self, family, friends. support /relatively/ steady growth.
Growing the economy is not "like a bicycle, the slower it goes the less stable it is."
See everything from ancient Egypt to Soviet-style Communism. Periods of time in Ancient Rome would fit in too. The problem with those -- except for a repressive political system -- was that we could not produce enough to satisfy everyone's basic needs.
Today, we can.
Much of the US-style growth is driven precisely by instability. The system feeds on debt. That forces stress. That forces growth. That also means one cannot be "better stewards of one’s self, family, friends."
And so far, no one has explained how "we don’t foolishly bully human nature with policy." Legal and economic frameworks guide what humans do; that's either something we think through and engineer, or it gets engineered for us by market forces, but it's there anyway.
The most freedom-preserving policy isn't a command system, but it's not a pure market system either. And for stability, we can contrast stable economies to boom-and-bust cycles and successful democracies to the very many failed market-economy democracies across e.g. Africa and South America.
You can be arrested, indicted, and held in jail on pretrial, and there is literally no recourse. There are many other ways jail can happen without due process. Where I live:
* Civil contempt. Absolutely immunity. No due process. Record is about 16 years. Having a bad day? Judge can toss you in jail.
* "Dangerous." Half a year. No due process. He-said she-said.
* "Insane." Psychiatric hold. Three days. Due process on paper, not in practice. Police in my town can and do use this if they don't like you.
Absolutely no recourse. You come out with a gap in income, employment, and, if you missed rent/mortgage, no home. Landlords will simply throw your stuff away too.
You're also basically damned if things do move forward, since from jail, you have no access to evidence, to internet (for legal research), and no reasonable way to recruit a lawyer (and, for most people, pay for one).
Can happen to anyone. Less common if you're rich and can afford a good lawyer, but far from uncommon.
The GP seems to be suggesting that there's no recourse at all, usually. You might bring suit against a police department or LE agency, but you'll fail to find any relief there. True that qualified immunity only protects individuals, but there's a raft of other things that makes it hard to get a judgement against a police department, too.
I think there's probably one major exception: civil rights violation investigations. But even then, the people doing the investigating seem to be biased toward the LEOs.
The GP's linked article doesn't seem to even talk about this, so not sure why that's there.
> You might bring suit against a police department or LE agency, but you'll fail to find any relief there.
I don't know if I'd go so far to say she won't find any relief, but it probably still could be a pretty tough Monell claim against the department (although it's hard to tell from the sparse details in the article):
"[A] local government may not be sued under [42 U.S.C.] § 1983 for an injury inflicted solely by its employees or agents. Instead, it is when execution of a government's policy or custom, whether made by its lawmakers or by those whose edicts or acts may fairly be said to represent official policy, inflicts the injury that the government, as an entity, is responsible under § 1983." [1]
I could see a problem if there was a policy/custom of relying on AI facial recognition alone without any other corroborating evidence (would be a really stupid practice, but I'm sure stupider things have become part of a police department's systemic practices). Or if there was a failure to sufficiently train detectives about the erroneous tendencies of this technology. Maybe the needlessly prolonged detention without bail could be an issue if there was a lack of adequate protocols to expedite in a reasonable amount of time.
Either way, still seems hard to say this a slam dunk case for her, unfortunately. But also seems too risky for the city of Fargo to not settle, at least nominally.
> "Insane." Psychiatric hold. Three days. Due process on paper, not in practice. Police in my town can and do use this if they don't like you.
And there are definitely insane people who are a threat to themselves and others who wander around, making the streets and public transit systems unsafe and unpleasant, who need to be put into something like a psychiatric hold by something like the police.
And if you don't have police and a criminal justice system that are willing and able to impose psychiatric holds, you wind up with a bunch of incidents where a crazy mentally-ill vagrant kills someone in a public (the Iryna Zarutska murder, or any of the various cases where a homeless person randomly shoves someone into the path of an oncoming train at a public transit station); or incidents where someone else gets railroaded by the criminal justice system for intervening in a crazy mentally-ill person threatening people around them (the Daniel Penny incident - many people, even nominal anti-carceralists, are upset that he was not successfully convicted and incarcerated for murder). Not to mention all the less-newsworthy incidents where insane people walking the streets and public transit systems systematically ruin them for everyone else, either through vandalism or theft or simply screaming incoherently at people as they try to use the public commons.
It's certainly possible for the police to abuse psychiatric holds if they don't like you; on the other hand, the existence of large numbers of people who should be in some kind of psychiatric hold but aren't disrupting and vandalizing the public commons is one of the biggest quality of life and physical safety problems in my region and in many other American urban areas.
Go to Florida, be arrested. Have charges thrown out, dropped, dismissed or simply be acquitted. Florida doesn't care, they'll bill you for your incarceration at nearly $100/day. And failure to pay this bill is, itself, a felony.
>* "Insane." Psychiatric hold. Three days. Due process on paper, not in practice. Police in my town can and do use this if they don't like you.
A friend of mine was committed longer than 3 days without council or the ability to represent themselves in the hearing. Apparently the whole process of being committed is ex parte in practice in some states.
This is a bit hyperbolic and the exaggerations really undermine what I think is your broader point (that there is rarely recourse when you're held for short to moderate amounts of time). It is hard for me to believe that someone was held for 16 years on civil contempt without due process or that someone was held for half a year without due process after being deemed dangerous. The reason that is hard for me to believe is that the due process is implicit in the action you describe. Civil contempt is from a judge which implies that you're already in court - that's due process. Someone being labeled "dangerous" implies that a finding was made by a neutral party - that's due process.
Just because you disagree with the outcome doesn't mean that due process wasn't given.
Yeah it's "due process." In civil contempt the judge is a witness and prosecutor in the very "process" they're judging. That's the most perverted form of due process imaginable.
A judge should have to recuse themselves if they are acting as witness to the supposed infraction.
Civil contempt isn't some roving criminal charge that jumps out of the jury box randomly. It's meant to make somebody comply with a court order. Anybody in civil contempt holds the keys to the jailhouse door in their own hands, all they have to do is comply.
This statement should make you uncomfortable. It makes me uncomfortable because it is a pure expression of the power of the state. But it's still due process.
In Criminal Contempt max duration of imprisonment is limited. In civil it is not until somebody decides that one never complies. You may call it due process. I call it for what it is - A torture and fucking crime against humanity. Judge that holds person for years for being stubborn deserves nothing more than walk the plank
Any power that could force a judge to actually walk the plank for what they see as an abuse of power, is itself something like a state, that could just as easily wield that power against the stubborn defendant.
Judges are not above the law. They could be and are being made to "walk a plank". Problem is that we have many laws that are very shitty and allow abuse and are heavily distorted to benefit anyone but "we the people"
> Then Iranians will be reminded how peaceful and prosperous the most other Muslim countries are.
This is factually incorrect. Top 10 majority-Muslim countries, sorted by population:
Indonesia, Pakistan, Egypt, Turkey, Algeria, Sudan, Iraq, Afghanistan, Morocco, Saudi Arabia
Now, the majority of those have problems with seeds in Western Imperialism, but the point is (a) the majority of those have problems (b) Iran's problems also have seeds in US interventions.
The gap between how peaceful and educated most people are, and how bad governments are, is a phenomenon almost unique here. Figuring out how to bridge that gap is the major challenge. The trick would be establishing a collective caliphate -- where the caliph isn't an individual but an institution -- and which spans the Muslim world.
Prototyping platforms have tiny markets, but lead to downstream sales. Many a company were brought down by more developer-friendly platforms ignoring the "tiny" userbase of people who want to do unconventional things.
Most IC vendors provide free samples and support because of this. That's a market size of close to zero -- electronic engineers -- but leads to a market size of "massive." I can get an application engineer to visit my office for free to help me develop if I want.
Arguably, iPhone and Android won by supporting the tiny market of developers, who went on to build an ecosystem of applications, some long-tail, and some unexpected successes.
And arguably, x86 won for the same reason.
Atmel had shipped 500 million AVR flash microcontrollers, due in large part to the ecosystem created by Arduino.
Balmer said "Developers! developers! developers!" Visual Studio was not a major revenue driver for Microsoft; what was developed in it was.
> Prototyping platforms have tiny markets, but lead to downstream sales. Many a company were brought down by more developer-friendly platforms ignoring the "tiny" userbase of people who want to do unconventional things.
Qualcomm doesn't even make small/cheap MCUs so they aren't going to win over that market by buying Arduino. Their first board post-acquisition is a mashup of a Linux SBC with an MCU devkit, and while the Linux SOC is from QCOM, the MCU is from ST Micro.
>Atmel had shipped 500 million AVR flash microcontrollers, due in large part to the ecosystem created by Arduino.
How do you know the 500 million sales is due to the Arduino ecosystem?
I used to work in embedded for 10+ years and in the 4 companies I worked at so far, none of the products ever featured AVR microcontrollers. The microcontroller of choice for production was always based on the feature/cost ratio for each application, never on the "is it part of the Arduino ecosystem?" question.
Tinkering with Arduino at home, and building products for mass production, have widely different considerations.
If they sold 500 million microcontrollers and your workplaces never bought any, then your experience doesn't tell us anything about why the people that did buy them, bought them.
All of the products that i've been involved with that included AVR microcontrollers are from before the Arduino platform existed. The STMicro ARM M3 chips are more capable and cheaper then the 8-bit AVRs; The Arduino IDE never factored into the decision, even at the height of its popularity.
FWIW: I've used Arduinos, but never with their IDE.
AVR was super-developer-friendly well before the Arduino. It replaced the PIC for a lot of hobbyist projects.
To the points in the thread, on major product development, these things don't matter. On the long tail of smaller products, as well as on unexpected successes, they do.
That is the downside. you can prototype with one chip and when the concept works switch. I've worked with many projects over the years where that was done. Sometimes an intern proved it works with arduino - which wat cheap enough to buy without needing supply management, but then we did the project with 'good code' on our internal controllers. Othertimes we bought a competitor andiagain first thing switched them to our controllers. (Our controllers are designed for harsh environments which means millions of dollars spent designing the case and connectors)
I remember having great fun in QuickBASIC. And my son enjoys Scratch.
Django code is much more fun to work with than Node, but I can't imagine developing something competitive in it in 2025 to what I'm developing in Node. Node is a pain in the butt, but at the end of the day, competitiveness is about what you deliver to the user, not how much fun you have along the way.
* I think the most fundamental problems are developer-base/libraries and being able to use the same code client-side and server-side.
* Django was also written around the concept of views and templates and similar, rather than client-side web apps, and the structure reflects that.
* While it supports async and web sockets, those aren't as deep in the DNA as for most Node (or even aiohttp) apps.
* Everything I do now is reactive. That's just a better way to work than compiling a page with templates.
I won't even mention mobile. But how you add that is a big difference too.
It's very battery-included, but many of the batteries (e.g. server-side templating language) are 2005-era nickel cadmium rather than 2025-era lithium ion.
I would love to see a modern Node framework as pleasant to work with, thought-out, engineered, documented, supported, designed, etc. as well as Django, but we're nowhere close to there yet.
You spell out a lot of examples, but all of them are purely technical. What is it that you can deliver to the user using Node that you cannot deliver using Django? This is a genuine question.
Man, the only true part is the async/web socket part (and it's most because of python and not django itself) ... you can do a lot, and by a lot I mean almost 99% of websites/apps out there, with django and it's 2005-era nickel cadmium features
The lithium-ion battery analogy seems fitting: When we're not careful about sourcing those modern batteries from a trustworthy supply-chain, they tend to explode and injure the user.
Amazon shouldn't sell returned products as "new," but as "open box."
The other way it happens is co-mingling. Some vendor sends an "open box" product to Amazon as new, or a fake product, and Amazon ships it out when sold by Amazon since it considers goods to be fungible.
I stopped buying anything which goes in my body from eBay, Amazon, and similar after receiving a premium food product with very clearly fake packaging.
Amazon broke in 2020, when most shopping went online. It never recovered.
I doubt it ever will. Trust takes a long time to earn, and a little bit of time to break. I had four or five incidents on Amazon, cancelled Prime, and I doubt it will ever make business sense for Amazon to get me back.
I do think there's a place for a competitor to Amazon right now which looks more like the old Amazon.
Starting one would be super-capital-intensive. It's not a lean startup. There's only a handful of organizations with the capital to do that, and I doubt any of them will, in fact, do it.
>I do think there's a place for a competitor to Amazon right now which looks more like the old Amazon.
If walmart plays their cards right, they can do it (I mean they did acquire Jet). Unfortunately they also seem to be OK with becoming a dropship frontend for aliexpress
In well-designed microelectronics, they will.
The standard circuit involves a fuse, a fast Zener clamp, and sometimes a small resistor (e.g. 1 ohm) and/or capacitor. The design parameter is that, with the current limit from the resistor, the Zener should not blow out before the fuse.
The resistor needs to be small enough to not lose a lot of voltage under normal operations, but to still protect the Zener during the short surge during which the fuse blows. For most microelectronics, that's not hard. A 0.5W USB device might have 100mA of current max, which across 1 ohm is 100mV, so negligible for most purposes.
With high-power devices, it gets more complex.
Of course, consumer devices (a) will never be fixed (b) don't sell on this (c) every penny counts, so there's no market pressure to do things right.
But that's how we used to do it, and how it's still done many places where things count. If I'm building a one-off or few-off, it definitely will have proper protection.
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