Had a pretty close childhood friend choose assisted suicide (in California) a few years ago after a year long battle with blood cancer. It's not easy to do, I think his biggest fear was losing his ability to consent as his mental condition declined rapidly. The link below outlines the process. He was getting home hospice care staying at an Aunt's house hear the hospital he was treated at. I don't think it is the right choice for everybody, but I certainly think in my friends case it was.
I used to test devices for USB compliance a long time ago. One of the things I often saw problems with was the inrush current test. Basically too much bypass caps on the 5v. I didn't see it mentioned in the article. It's really easy to get focused on the high speed digital design but for compliance it's sometimes the less sexy stuff that gets you. No idea how this stuff works with newer versions of the standard but it seems like there still is a test. Nice article though.
What devices do people use to limit inrush current? You can make a current limiter with a few transistors, but I'm guessing there must be better integrated solutions (e.g. with temperature protection, etc.)
I only saw this topic recently. Sorry for replying 2 days after everyone else has left...
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I like the pMOS constant-slew rate trick myself.
A number of voltage-regulators have soft-start ramp-up already built in. But if your project doesn't have one, you can build it out of pMOS pretty easily. With just a resistor + capacitor on the pMOS (serving as negative feedback, to slow down the start), you can arbitrarily slow-down inrush current to whatever values you wish.
Constant-slew rate voltage control vs a capacitive load effectively creates current-controlled startup functionality. So its "good enough" for most people's purposes (assuming capacitive loads are what's causing you to be worried).
So its a bit of an A-problem vs B-problem here. I'm giving you a slew-rate controlled soft start circuit when you asked for current control. But... its probably what you want?
> but I'm guessing there must be better integrated solutions (e.g. with temperature protection, etc.)
I believe the "proper" solutions are called a "load switch", of which there are a huge variety of integrated chips and MOSFETs with load-switch (constant slew rate + temperature control) solutions available.
Things get rather complicated as you edge into "proper" solutions. I'm just a hobbyist though, so I don't have much experience with these "proper" designs.
EDIT2: Maybe that NXP Load switch is a bit "too full featured" for most projects. This TI one I found seems to be more mainstream and simple. TPS22950CQDDCRQ1 (https://www.ti.com/product/TPS22950-Q1)
You can use inductors. Some USB cables have a choke on them. But basically the problem is when a large amount of circuitry all powers up at one when you plug in. So everything connected directly to USB 5v with a lot of large capacitors to filter the power. If you really need that then you can self power and avoid the problem.
If the answer to excessive in-rush current (due to capacitance) is to add series inductance, then: Isn't the more-efficient answer simply less capacitance?
I think the correct answer really depends upon what you are trying to do. Sometimes where board space and cost are not an issue people use a combination of larger and smaller bypass caps to reduce switching noise. I don't think there is a one size fits all solution because people power many different types of things from USB. It's more just a caution about USB power in general. Most people know the 500mA current limit, but in-rush compliance is something you don't really see in functional testing because typically you can get away with a violation and the board will still work.
AMC7135 might work: it's a linear LDO fixed current regulator designed for driving LEDs, which internally is basically an N-channel MOSFET which holds it's gate voltage in the linear region and actively adjusts it to provide constant current.
Silicon based chips rely on oxide and metal layers to connect the transistors. Not clear to me from the article how that would work for graphene based devices. This was also an issue for GaAs based chips. From the Wikipedia article on GaAs
"The second major advantage of Si is the existence of a native oxide (silicon dioxide, SiO2), which is used as an insulator"
William Gibson's novel the Peripheral (2014) and Agency (2020) have characters who control implanted smartphones (like a HUD on your eyes and audio channel built into you ears) that are controlled by using the tip of you tongue on the roof of your mouth. It's possible he was inspired by the video or some other source but yeah it's clear the idea has been around for a while.
IIRC the book(s) mainly referenced "subvocal" controls, based on detecting almost-talking movements within the user's face/throat/voicebox.
I'd argue those are qualitatively different, more like a modern-day system of saying "AssistantBot: Send E-Mail", as opposed to a geometric mapping one could use for, say, painting a picture.
I absolutely agree that it's not for beginners, but amateurs can still have fun. I did the NNG in lean 3 and again lean 4. It didn't take me 100s of hours but I've also spent a lot of time over the last decade trying to brush up my math skills. One of the main problems with proofs is other than having a mathematician friend who's willing to check its really hard to know if you did it correctly. My son is a mathematician and I still didn't want to ask him to check my proofs! The cool thing for me about lean is I can do some form of math proofs and not have to ask somebody if I got it right.
If you liked that you might like the natural set game as well.
The author of the math book "How to Prove it" Daniel Velleman who I think did the set game also has a "How to Prove it with Lean" which is nice because the exercises correlate to the book.
I've found the lean community on zulip really open to amateurs to want to learn. I asked what I considered a "duh" type of question once I saw the answer, and the guy that helped me is kind of "the lean math" guy.
I have a graph from "Expert Political Judgement" that I've kept on a cork board for over a decade. It's from page 55 in my edition. It charts "Objective Frequency" vs "Subjective Probability" It has three curves, Experts (people in Government, paid to make political assessments), Dilettantes (people who are well read, read NYT, WSJ and the like), and College Undergrads. The Expert and Dilettante lines are more or less on top of each other. The undergrads are observably much worse and farther from the "Perfect Calibration line" that is a 45 degree line between objective frequency and subjective probability. So it's not the case that there is no difference in people's ability to predict political events, it's that so called "experts" are no better than people who follow current events closely. This was for me the main takeaway from the book, is that nobody can predict political events very well, but some groups are measurably worse than others. Tetlock has a brief section that somewhat mirrors your argument on page 186 "Misunderstanding what game is being played" where one expert tells him making predictions is all about getting your sound bite out, not about being correct. In this game, stronger, incorrect predictions might be advantageous in that they can change the narrative.
Right, and then he followed this up with Superforecasters which is all about the people who are on that 45 degree line. They exist! They just aren't popular.
For me are three distinct things
Japanese curry Japanese style of the Indian dish often made from an instant roux package and usually served over Japanese style white rice
Katsu Curry the same dish with a deep fried pork or chicken cutlet put on the the rice before the curry is poured over
Curry rice - no cutlet, the curry is mixed in with the rice before it's served.