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8mbonn | How do electronics accurately know time? | Technology | explainlikeimfive | {
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"Things like digital watches and computers have an internal oscillator (quartz chip). When an electric current is applied it vibrates with a known frequency, this frequency will be converted then into hours/minutes/seconds. It can drift over time as not perfectly accurate. Phones and computers using a network time application will get their time from the network. This is provided by atomic clocks which vibrate much faster than quartz and are incredibly accurate.",
"Actually, a second is a really well-defined unit of time. We need to do that when we are concerned with standard units. A second is precisely 9,192,631,770 oscillations of the Caesium atom. This is how atomic clocks compute time. How computers do that though is beyond me.",
"Imaging you have a bucket that you need to fill with water. You out the bucket under the tap and stay filling it up, this takes time. In fact, they used to make \"water clocks\" that did just this. Instead of a bucket, electronics uses a capacitor, which in this case works just like a bucket. When the bucket is full, X amount of time has passed. Do this hundreds, thousands, or billions of times per second and you have a very simple and reliable clock. Instead of a capacitor, most computers today use a crystal instead. Instead of filling a bucket however, it works similar to a tuning-fork. When a tuning-fork is hit, it makes a single tone; when a computer crystal has electricity applied, it makes a tone as well. This tone is so consistent that I can count the ups and downs (or filling and emptying of the bucket) to track time."
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8mboqk | What exactly have allowed each console generation’s graphics to improve? What do we have now that we didn’t have before? | Technology | explainlikeimfive | {
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"Graphics is just calculations, and better hardware can do more of them per second, allowing more lighting, shadows, complex models, and higher res textures to be rendered within a shorter time, leading to a higher frame rate. [I give a pretty lengthy explanation of some of these calculations in my answer here.]( URL_0 ) There are also improvements in memory access with newer hardware, which can reduce stuttering and freezing when moving from one area of a game to another as the hardware can more quickly load the data needed to render the new area. Look at how good today's games look with skyboxes, mirrors, refraction, reflection, shadows, thousands of polygons, and high resolution. We could do all of that years ago, but it would take days for hardware of a similar price to your console to render the scenes that it takes your console a fraction of a second to render. We've always been able to do the calculations needed to render these scenes, they can just be done more quickly now, to the point where they can be rendered in real time, 30+ times per second. The most important improvement to note is the increase in calculations per second per dollar. We've always been able to do the calculations, it's just gotten cheaper to do them more quickly as hardware design and manufacturing improves.",
"One big part is that the manufacturing technology for integrated circuit get more and more advanced. Each transistor get smaller and faster so you can have more on a chip with the same size at the same cost. The result is higher and higher performance.",
"A lot of people cited the hardware being incredibly more powerful, and that's true, but the software is also much more mature. The industry grew. Initially you had to write your videogame from scratch, in terrible hardware specific language. Nowadays, you can rent/buy a game engine and get triple A graphics out of the box. You would still need to design the assets... but really soon, software will take care of that too! Seeing how fast Nvidia is making progress on that front, in two years you get automatically generated animated 3d models and environments.",
"In addition to the other answers here, I would argue that better algorithms have had the most profound effect. Every so often, someone comes up with a new way to calculate lighting or physics or what have you that is as good, or better, at fooling humans than the current algorithms. Consider these algorithms, which run on the same hardware, but at significantly faster speeds. [Fluid Simulation]( URL_0 ) [Light Transport]( URL_1 ) [De-noising]( URL_2 )",
"* More memory to store more high quality models and textures * faster memory to draw more stuff in higher resolution in a single frame * higher throughput chips (higher frequency and more cores) to do more involved calculations such as improved light models, shadows etc. * better understanding of the requirements leading to better designed systems most of the above are a consequence of chip production improving and allowing more logic in the same area running at higher frequencies.",
"A few things. 3D GPUs with polygon graphics being the main one of them. But even with that, an NES could easily render a very complex scene from a modern 3D game. But it would probably take hours to render a single frame. The main thing that has been advancing is clock speed: the NES had a 1 MHz CPU, while some modern CPUs have above 4 GHz. Basically, a Hz is an operation per second, except many CPUs take multiple cycles to execute some operations. That isn't all - CPU technology has advanced a lot, adding things like parallel execution, which is executing multiple unrelated operations at the same time, and pipelining, which is dividing operations in stages and executing multiple operations in different stages at the same time to further lower execution times, out-of-order execution being executing other unrelated operations while the current one is waiting for something, etc. Basically, since the 80s CPUs have gotten not just about 4000x faster, but are also able of doing a ton of things at the same time, which makes it an even larger difference. And we aren't quite done yet. True life-like rendering is a form of rendering that even today's hardware would take a lot of time to do. It's called raytracing; tracing light rays from the observer until they hit lights. It's the opposite of real-life rendering, which is because tracing from lights to the eye is even harder. Today's 3D graphics are a sort of fake graphics where each triangle is drawn on the screen then each pixel is processed to approximate proper lighting, shadowing and things like that. But it's just an approximation, and a rough one at that."
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8mcj4c | How do finger print sensors work on phones? | Electrical signals? | Technology | explainlikeimfive | {
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"An **optical scanner** works by shining a bright light over your fingerprint and taking what is effectively a [digital photograph]( URL_4 ). If you've ever [photocopied]( URL_3 ) your hand, you'll know exactly how this works. Instead of producing a dirty black photocopy, the image feeds into a computer [scanner]( URL_1 ). The scanner uses a light\\-sensitive microchip \\(either a [CCD]( URL_2 ), charge\\-coupled device, or a CMOS image sensor\\) to produce a digital image. The computer analyzes the image automatically, selecting just the fingerprint, and then uses sophisticated pattern\\-matching software to turn it into a code. Another type of scanner, known as a **capacitive scanner**, measures your finger electrically. When your finger rests on a surface, the ridges in your fingerprints touch the surface while the hollows between the ridges stand slightly clear of it. In other words, there are varying distances between each part of your finger and the surface below. A capacitive scanner builds up a picture of your fingerprint by measuring these distances. Scanners like this are a bit like the [touchscreens]( URL_0 ) on things like iPhones and iPads.",
"Basically when you register your fingerprint it scans it and maps various points of interest on your fingerprint. You repeat it so that it determines that those points of interest are repeatable. It then records those as unique identifier. When you go to unlock your phone it again scans the finger this time looking for the points of interest it has recorded. If they match a certain percentage then it unlocks."
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8mf1fs | How do modern vehicles prevent wireless keys from being locked inside? | Technology | explainlikeimfive | {
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"As a person that’s worked at a Car rental place. They really don’t, most cars will give you a message in the dash about keys inside but that’s about it. I’ve had to deal with locked cars that are keyless and having to unlock them with tools. Hell, you could even start your car up go back inside and leave the keys inside and you can still drive the car without the keys just don’t turn off it off."
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8mmi4k | Why do video players always require user action after they start buffering? Almost every application, YouTube, iFunny, Reddit, needs me to press pause and play after loading instead of just starting the video again. Why? | Technology | explainlikeimfive | {
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"Be careful what you wish for. The current behaviour, as I understand it, was in response to large numbers of users **complaining** about auto-play; people **wanted** to control when videos started, and not have three of them playing simultaneously.",
"Do you have any kind of click-to-play addon/plugin installed?"
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8mmp5f | Why does traditional animation age better than CGI animation? | Technology | explainlikeimfive | {
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"A couple of reasons. It's not so much that Toy Story looks bad, it just doesn't look as realistic as modern CGI and realism is what you're judging. You're only expecting Snow White to look like an animation; by realism standards it's terrible. The other reason: 80 years ago, painting/drawing technology was pretty much the same as now. 20 years ago CGI technology was way behind where it is now. It'd be more like comparing cave paintings to traditional animation.",
"With hand-drawn animations like Snow White, you're not expecting reality. You're expecting a simple representation of reality, more of a gesture, really. CGI animations like Toy Story are close enough to reality for you to have a sense of expectation that never gets satisfied due to the limitations of the technology. It's the little imperfections of life that are difficult to quantify, thus difficult to render. We don't really notice these subtle imperfections in real life, but we surely notice when they're absent. This is something like the [Uncanny Valley]( URL_0 ).",
"3D Animation was in it’s infancy in the 90’s (there are a few pieces full-frame 3D Animation from the 80’s, but those are mostly clips and proof-of-concept segments). It was not only a developing art form, but a developing art form running on a developing technology. 2D Animation was well beyond it’s infancy-stage by the time Snow White was released. You could argue that 2D Animation made in the 1920’s hasn’t aged very well either. Most pre-1930 animation and almost all pre-1920 animation function more as a historical curiosity then entertainment nowadays. I don’t know too many people who could binge-watch Koko the Clown, Felix the Cat or even the oldest Mickey Mouse cartoons. Disney made massive improvements to 2D animation between 1928-1938. Compare [Steamboat Willie - 1928]( URL_1 ) with [The Old Mill - 1937]( URL_0 ). Snow White was the first 2D full-feature, but it is also the culmination of skill and experience that Disney had acquired the previous 10 years. It’s not really fair to compare Toy Story to Snow White because they were at different stages of development in each of their fields. 2D Animation techniques were practically perfected when Snow White was released, whereas 3D Animation techniques weren’t nearly as refined when Toy Story was released. The only things keeping Toy Story from feeling *really* dated is that Pixar chose a subject matter that the technology could render decently convincing at the time (plastic toys). And that Toy Story had (and still has) excellent direction.",
"It's interesting to know that one of the reasons they went with Toy Story was because they knew the limitations of computer animation at the time and since the main characters were all made out of plastic, the little things like moving hair, that make for great cgi, weren't as noticeable. So smart in that the mediums own plastic feel at the time was a bonus for their animated toys."
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8mmpcv | I often get spam emails from people who obviously did not send the emails. How does this happen? Is someone hacking their account? | Sorry if this is a previously discussed topic. I tried to search but the search function doesn't seem to work. I often get obviously spam email from some random person in my contact list. Are they hacked or am I hacked? How can someone spoof the person and send out email from their account? | Technology | explainlikeimfive | {
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"Often times, the account that appears to be sending the message did not actually send it. The “from” address is basically being forged. In internet parlance this is called “email spoofing.” There is phone spoofing too (fake caller ID information) which is a freaking epidemic in the U.S. these days. The person whose email/number is being spoofed can’t do anything to stop it.",
"No one is being hacked, the sender is just saying it's their email. Think of it like the return address on a letter. Anyone could put your friend's address there and send you a letter and it would look like it came from your friend. EDIT: And there's not really anything you can do about it, sorry.",
"Yes, someone has been hacked. No, it's probably not you. It may or may not be the person who the email appears to be from. It's trivial to send an email with whatever you want in the \"from\" header. Forging that field is easy and does not indicate that the email actually originated from that person's account. However, the fact that you received a scam email which appears to be from someone who is in your contacts list means that the scammer who sent the email has access to *someone's* account, and that person has your email address in their contact list. Let's say I'm a scammer and I hack into your email account. I now have access to your contacts list, and I want to send scam emails to everyone you've ever had contact with. Let's also assume (for whatever reason) that I don't want to or can not actually use your email account to send the emails. What do I do? I still use your email address as the \"from:\" in the scam emails I send as it's more likely to get through to their inboxes and it's more likely that they'll fall for it. I may also randomly select other email addresses in your contact list and cycle through them as the forged \"From\" to avoid other types of spam filtering. In short, someone's email was hacked or the scammer would not have the contact list to begin with, but you can not assume that the hacked account is necessarily the one which the scammer forges in the from line.",
"Everyone is mentioning how easy it is to spoof the emails but how WOULD someone know what names to use unless they had access to your account? I get the same thing, usually delete em, but I've had the same address since high school and only seem to get these targeted emails based on 2 names \\(and neither one I've corresponded much if at all with through email\\)."
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8mn803 | How do TV/Radio stations know how many viewers/listeners they have at specific times? | Technology | explainlikeimfive | {
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"URL_0 A company selects certain individuals to install a box on their TV that captures information of what they are watching. Based on how many people participate they can gauge what the rest of America is watching e.g. if 75% Neilsen families are watching Family Guy then they can reasonably predict that 75% of other families are watching it."
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8mnukn | What’s the difference between IPv4 and IPv6? | Technology | explainlikeimfive | {
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"Computers, like houses, need addresses. The internet is a city, and this city is being built. With IPv4, the city planners we only allowed to use numbered addresses up to 2^32 unique combinations. With IPv6, the city planners are now allowed to use both letters and numbers, up to 3.4 x 10^38 unique combinations."
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8mo8fc | How do air conditioners work? | Technology | explainlikeimfive | {
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"When you compress a gas, it becomes hot. You can observe this by for instance inflating a tire. When you uncompress a gas, it becomes cold. You can observe this by using a spay can. The air conditioner uncompresses the gas on the inside, which makes it cold. The warm air in the room then warms the gas, transferring some of the heat into it. Then the conditioner moves the gas to the outside, and compresses it. This makes it hotter than the outside, so the gas cools until it's at outside temperature. Then it starts the loop again. Metaphorically you could view the gas as a sponge. The sponge is uncompressed inside and absorbs heat, then is moved outside and the heat is squeezed out."
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8mp5yo | Why are speakers arranged with woofers on the bottom and tweeters on top? | Technology | explainlikeimfive | {
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"Two reasons. First, subs are heavier because they have thicker membrane and bigger coils. The second one I can't explain that well in English, so I'll have to keep it at low-frequency noises tend to be less directional so it's not important to have them at head-height. This is also why tweeters are slightly tipped when they're overhead.",
"Our ears are less sensitive to the direction of bass frequency sound versus higher pitched treble frequency. So the larger woofer speakers position in the room is not quite as important to our enjoyment of the sound. This is for instance why subwoofers are often located to the side without needing as critical a placement. The smaller tweeter speakers need to be positioned very accurately though in order to provide realistic sound, and they need to be close to ear level in order for the music to be as clear as possible. By placing the tweeters at the top, they bring the sound up closer to your ears."
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8mppbo | Wait so how does WinRar make money? | Technology | explainlikeimfive | {
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"Basically it makes revenue from companies who have to have their documents signed and legalised. You as a regular user don.t need those features, that.s why the program is free. Also is free directly from the creators to discourage piracy."
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8mq6xg | What is machine learning? My computer engineer sister talks about it a lot and I don't understand it. | Technology | explainlikeimfive | {
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"Machine learning is pretty much in the name. It’s a machine that is programmed (by humans) to teach itself something (without humans). Machines most commonly do this through some form of recursion (where the input data is manipulated over and over again in the same manner until some valuable information can be derived from it). Basically, humans make a program and feed it some data. The machine then learns something about the data by itself"
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8mq9a0 | Why commercial airplanes are usually white while military airplanes are usually grey? | Technology | explainlikeimfive | {
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"3 main reasons : 1. Minimizing visual signature . Aircraft operating over sea can be camouflaged by painting them blue\\-grey. 2. Blending of aircraft with the tarmac. Parked aircraft outlines are harder to see if the aircraft color doesn't provide sharp contrast with the surface they are on. 3. Modern military aircraft are painted with radar absorbent paint . The paint is most effective with darker colors and a matte finish. Hence, grey aircraft.",
"Airliners *want* to be seen by other planes, military planes *want* to hide from other planes. White is easier to see in the sky than grey. White is a simple base color on which you can easily put other colors of paint or decals. White reflects the sun, which can help keep the plane cooler (and more comfortable for passengers) on hot sunny days. This cooling effect can also help some (non-metal) parts of the plane last longer, as thermal cycling can wear plastic and composite parts out more quickly.",
"On the commercial side, it's entirely a brand consideration. Spirit Air paints all of their planes bright yellow, for example. UPS paints the back half of their planes dark brown. Southwest uses a purply blue color. As for why white is the most prominent, it's historical, and I'd assume related to white being associated with cleanliness, polish and professionalism (on account of white providing a good contrast to see dirt and damage)."
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8mrsgg | How do mobile services, that are disabled while in airplane mode, interfere with an airplane? | Technology | explainlikeimfive | {
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"They don't. However, if an airplane was built incorrectly, it is possible that the signals send out by your mobile phone - mostly radio and microwaves - could induce an electric current in either the instruments or control circuit of an airplane, and while this is incredibly unlikely the result could be that you and several hundred of your closest (physically) friends would die. Since the cell network is too short and too slow acting to use while travelling much more than a hundred mph everyone agrees that we'd rather have more battery on arrival than take that chance. Well, everyone except the jerk in 79B that is.",
"Aside from issues with the plane, it is also a heavy load on the cell network. To connect and make calls, cell phones communicate with cell towers, which cover the phones in a certain radius. When a phone moves across the edge between areas covered by two towers, the towers communicate to keep a potential connection from a phone call alive. This exchange was designed for phones moving much slower than an airplane. When a plane zips through many towers' zones quickly, the towers try to do this communication, but the phone has already entered a new zone by the time they finish, just wasting that communication. Multiply this by the hundreds of phones in a plane and the cell towers will only be able to talk to each other to negotiate the transfer pf all these phones between their zones, preventing a lot of normal use communication from getting through to the network."
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8msk08 | Why is there an option to overwrite my hard drives with 0 MULTIPLE times when formatting | Technology | explainlikeimfive | {
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"It's due to a theoretical attack to recover information. When you write a 1 or 0 to a mechnical harddrive you are basically stamping a magnet dot on the platter. However the *exact* placement of that dot is not precise. Since you need the head to be able to read that dot later on you make the dot big enough that even if the two are not lined up perfectly (the head over the exact center of the dot) the head will still be over part of the dot and so will read the correct information (a 1 or a 0). This creates the *possiblity* that someone could take apart the harddrive in a lab, scan it with a high precision head and then try to reassemble the data by looking for previous dots that where not perfectly overwritten - essentially looking for the edges of previous dots peeking out from under the current dot because it wasn't lined up perfectly with the old one. To my knowledge this hasn't actually been done in a practical scenario and most people that concerned someone would go to such lengths (such as governments or big companies) simply follow the practice of erasing the data and then violently shredding the harddrive.",
"Because of a misunderstanding. I wish I could remember the names involved, but decades ago someone wrote a paper about theoretically being able to recover information that was physically overwritten on a hard drive. It was very quickly invalidated by increases in efficiency in how hard drives recorded and wrote data. But what he mentioned about a POSSIBLE attack vector was reported and repeated as a DEFINITE attack vector. There has been no recorded instance of data being recovered from an HDD after a single 0 wipe that I've ever been made aware of. There was a reward publicly offered for a long time to anyone that could and it was never collected. A single 0 wipe is fine to securely destroy data on an HDD, and anything more than that only increases the time you spend erasing it. That having been said, no, you should never do even a single 0 wipe on any drive to erase it; an ATA secure erase is faster and just as secure (assuming the drive isn't so old that it doesn't support it), and if we're talking about an SSD a complete 0 wipe just flat-out won't work because of wear leveling (it won't write sector by sector, it'll write to the least used sectors - so the process won't fail but you won't reach your intended outcome of securely erasing data and you likely won't realize that if you don't know about this). But if you wanna have fun bust out dd or diskpart and go to town with them zeroes. I'm not judging. If your data is just too important to even risk a breach from an attack that only exists in theory and rumors, then physically destroy the entire drive. Depending on the method physical destruction can be even more fun.",
"This is only useful for magnetic drives. NAND flash of SSD's store ones or zero's and there's no ghost to erase. Dealing with analog systems like magnetic storage means there is room for unintended consequences of the medium. The magnetic markers of some \"files\" could be left on the platter in a \"ghosted\" manner meaning they could be recovered either partially or in full when only a single write of 0's is employed. Multiple zero writes will ensure nothing remains. Imagine if you had a white wall with a 2\" strip of red paint halfway up the wall all along it (like a chair rail basically). If you wanted to cover that red paint you could take your 2\" brush and with a single long stroke you could carefully paint over it with the same white color as the rest of the wall. You'll probably cover 99% of it but after it dries you'll still be able to see that red stripe through the paint and there might be some edges of pure red that poke out around the white. The next step would be to paint over it 7 more times with white, both above and below and on top of it thereby wiping away any trace of the red line. Is it necessary to do 7 passes of 0's for a format? No, not unless you've got state secrets or billion-dollar IP. The paint metaphor is a bit strained as red paint on a white wall is probably the worst combination to try to cover up and seeing paint color through another layer is not really how it works with magnetic storage but i used it specifically to paint a picture in your mind. Not to mention the fact that 7 extra layers of paint in the middle of the wall would look like shit, IRL you would just paint the whole fucking wall."
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8msvsl | What is the point of region locking? | Technology | explainlikeimfive | {
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"Games are significantly cheaper in different areas. So it stops people in Brazil going to the US and mass purchasing considerably cheaper games/movies So they lock it by market region to stop people doing that. EDIT: I remembered the Brazil fact backwards, they are one of the more expensive ones"
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8mtjfc | How was the transatlantic telegraph cable laid in the 19th century? | Technology | explainlikeimfive | {
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"The warships HMS Agamemnon & USS Niagara were converted to hold a spool of cable. This cable was made of 7 copper wires and waterproofed with hemp and tar. The ships just unrolled the entire spool behind them as they travelled and eventually joined the 2 cables together. The cables failed and broke on their first, second, third and fourth attempts, forcing the ships to go out to sea with replacements and attempt to make repairs. On 10 August 1858, the first test message was sent from Ireland to North America and successfully read 2 days later. The first official message was sent on 16 August 1858. Modern cable laying vessels use the same principles as the first transatlantic cables, although the materials and equipment have been upgraded. Fibre optic wires are used instead of copper wires, repeater stations are installed to boost the signal and prevent signal loss, gps markers are placed to locate the cables easily and many many improvements allow us to transmit information quickly, reliably and easily."
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8mtn3x | How were recordings taken during WWII? | I've been watching some TV and noticed that a lot of the camera angles are ahead of the moving tanks, even when they are firing, like there are dedicated camera men in battle. Same thing goes with planes. It seems like recording footage would need a dedicated group because you shouldn't be recording mid-battle. | Technology | explainlikeimfive | {
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"Militaries have members who's duty it is to record and photograph combat and other activities. They are collectively referred to as \"Combat Camera.\" A lot of the footage you see in documentaries is also staged footage of exercises and demonstrations for propaganda and training films.",
"If the images is from aircraft and show when it fire it is likely from a [gun camera]( URL_0 ) There where cameras mounted on the aircraft that started to film when the gun was fired. It was used so you could analyse how effective the tactics where and how pilots fired and when they hit/killed the target. So they was a important part in developing tactics for air combat. You only have ammunition for a few second of fire and it is hard for the pilot to notice it they hit the target and you can't have other observers like in ground and at sea so cameras was used. If the camera is in front and looks back at advancing troops from your own side is was staged/taken during training. But there are combat foto by cameramen among the troop so if is from behind/from the side it can be genuine.",
"Combat Camera is usually a soldier/Marine embedded with a combat unit SPECIFICALLY to capture the battle. For lots of reasons, not the least of which is future TV shows."
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8mvubn | How do geosynchronous satellites, like those of TV providers like DIRECTV, stay in such a perfect orbit such that they can always provide a signal? | Title says it all. How does it work? | Technology | explainlikeimfive | {
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"In short, geosynchronous orbits are what they are because anything orbiting them does so at the same speed as the earth rotates. That is, in order to orbit at a geosynchrnous orbit distance, you *must* orbit at the same speed the earth spins, and thus stay above the same spot on the earth at all times. Getting these speeds is no more difficult than achieving orbit speeds at any other distance: geosynchronous is just notable because it is the distance from Earth that happens to be this correct speed."
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8mvxug | Why are $25 amazon tablets seemingly more advanced than multimedia centers in luxury cars? | Technology | explainlikeimfive | {
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"Amazon tablets are based on the Android operating system, something that is already established. Multimedia centers in luxury cars are systems are built from the ground up by that manufacturer to be integrated into the car's other systems.",
"Also, car components are probably selected and developed years before it's released. And car product cycle is like 5 years where things don't change.",
"Other people have gone into the software, but another factor is the hardware. All the electronics, including the screen, have to be able to work in an extreme range of temperatures. That screen needs to work on a winter day when it's-40 just as well as a summer afternoon when the inside of the car is 150 degrees. Touch screens that can handle temperatures swings like that aren't known for their responsiveness, and are not cheap to boot. Your cheap Amazon tablet is not made to work in those conditions, or to repeatedly cycle between them.",
"Another factor that someone with more expertise could expound upon is the fact that cars are subject to very stringent regulation. This makes the development and testing of large software programs meticulous and expensive. Thus, manufacturers tend to stick to the bare minimum.",
"The simplest explanation is that car companies are terrible at building infotainment units. This is because of a few factors: - Cars don't get \"upgraded\" - you refine one component, and then reuse it for several years in many models without a plan for replacing it in already existing cars. If a head unit is passable in 2005, it will be trash in 2009 but still be installed in new cars. - Reliability/safety standards - car makers do not like building things that fail quickly. As a result, infotainment setups tend to be bulky and use well-tested (which translates to slow) hardware. They also lock users out when the car starts moving, because every single time someone slips up and hits the gas instead of the brakes, they start a media frenzy. Look how bad it is for Tesla - people ignore Autopilot's repeated warnings and crash, but it's still somehow their fault. - \"Not made here\" syndrome - Luxury cars _have_ to be exclusive. This means that every automaker tries to build their own system. None of them are actually willing (or able) to invest the money to make them polished and smooth, and it shows. These are slowly changing with companies like Tesla and services like CarPlay and Android Auto, but broadly speaking none of these apply to cheap Android tablets or phones.",
"The inside of a car is a hellish environment for electronics. It gets really hot, there's heaps of vibration, and the electric supply is a noisy mess. Stick any standard tablet computer to a car's dashboard and it won't last 6 months. But when people buy a car, they expect the dashboard equipment to last at least 10 years. This means that car entertainment systems have to be built very differently from tablet computers. As a side effect of this, the car's systems won't be refreshed every year, and even if the software's look is updated between models, the hardware is often the same as what they were using 5 years ago.",
"Multimedia systems for cars are being built and tested by huge bureaucratic companies years before they make it into a production vehicle. By the time an infotainment unit hits show rooms floors it is already outdated.",
"Hard answer? Because the electronics in Android devices are specialized for speed, not durability, and they are not required to function under federal motor vehicle safety standards. Any android device (or apple) would shit the bed if it was asked to fire up when it was -40F or 150F or had its internals covered in road dust or slammed around across potholes day in and day out or had requirements for full functionality within a few seconds of power-on. They sure as heck wouldn't perform well for as long as a car will during its useful life. Pay attention to the MASSIVE problems Tesla is having with the Model 3 center console. That is a car system that's designed with standards closer to a consumer grade unit, and it's a hot mess.",
"One answer I've not seen here is that Amazon uses their devices as a platform to sell you more stuff. If you buy a tablet from them, chances are you'll be using their app store and will be paying for more. They price the tablets so low because they know it'll enable more sales. They're possibly loss leaders. Car manufactures aren't going to make more money after the sale of their car, so their multimedia services are literally the cheapest they can get away with. Edit: my spelling was atrocious.",
"An Amazon tablet can’t survive the temperature swings an automotive display has to. Take the display in my Jetta. It’s worked at -26F and 112F (outside temp, no idea how hot in the car). Toss a tablet in the freezer for 7 hours and see how fast it powers up",
"A lot of manufacturers develop their own software. What they need to do is just build their own android or ios devices and run Android/Ios in their systems. Some cars are starting to do this now. I.e. \"Android Auto\". Really, I think even that is not needed. What I think should happen instead is creating a standard port for mobile docking on phones. Take USB/HDMI and combine it into one port. Then make cars that can accepts phones of any size in the dock, where the phone is your cars entertainment screen. Then you just install the APP for your car and you get access to all your cars features and your phone is the electronic hub of your car. It would still have a CPU for monitoring all the car sensors, but that would be relayed to the app on your phone over that docking port. So the docking port would be on some kind of mount that sticks out of the cars center dash area where a radio would normally be. It doubles as a sturdy mount for your phone. Also, this would allow different drivers to have different configurations for everything. You dock your phone everything is the way you want it (the mirrors, the seats readjust electronically, etc etc). Spouse docks there phone it all changes to them. Etc. And you can upgrade your phone to upgrade your cars entertainment processing power. Play music on the phone, comes out of the car. Control the car volume with the phone. I.e. the phones volume controls control the cars speaker levels. And the Steering wheel controls would interface to that dock port too, and work to control the volume and up/down/left/right in menus in the app etc. This would save manufacturers a lot of R & D money, and decrease production time. As well as simplifying trim packages. But they could still sell upgraded amplifier/speaker packages. And if buyers don't have a phone, they could sell a dumbed down (non cellular) device that does everything but can't make calls or send texts. With this model, manufacturers would be using the power of existing phone manufacturer competition to create their entertainment systems. Now all the car makers need is app developers. This would also combat phone use while driving as a national safety standard. No phone in dock, car doesn't run. Phone in dock and car running, you can't send text messages using the phones screen. You can only read text messages on OSD's on the windshield (if the car has one). It should limit the phone to basic road safe functionality. Basically forcing road safety phone usages nationally. Honestly, I think it should be a nationally required design to some degree. Where all new cars past X date have to be built this way. They could take it a step farther in having Bio Metric Keys. So you need a biometric key to start the car. If there are multiple drivers each need they're own key. So whoever is driving, is the phone that has to be in the dock. Or scratch the Biometric key and just bake it into the app. So when you start the car, you have to scan your finger on your phone via the fingerprint reader so it knows you are the owner of that phone and that's the phone in the dock. Take it one step farther and link it into the DMV. License expired? Nope, car won't run for you unless you declare an emergency, which would be followed up by the police. Phones already have navigation, awesome audio players, video players, and so on.... Why develop the same stuff in a car... It's redundantly dumb. Someone like Toyota, should get with someone like Samsung and work together to develop the app, and the docking port in a new phone. Sell the idea in something popular like a Toyota Corolla... If it takes off, everyone will want it and soon all phones will have said Docking port. Edit: This would also solve heat/cold problems, and theft. When you leave the car you take your phone with you, nothing to steal. No ones going to break in and take your door speakers out (not usually...). And if the car gets to hot for your phone, you won't be in it and thus neither will your phone.",
"Someone else answered it already, but to break it down more, everything in a car is made many many years ahead of time. They test it to make sure its not going to crap out in a year. All the tech in your car is made at least 5 years+ ago. A $25 tablet today, would be the quality of an Ipad 5 years ago.",
"One example of why vehicle grade hardware costs more (and there are literally hundreds of reasons why) is the nitz / brightness needed to be perfectly safe and legible in direct sunlight is way beyond requirements for tablets and phones. The suppliers of screens with those specs are not nearly as common and will ask for way more money to build them because of the comparatively lower volume.",
"In car entertainment has to be resistant to lawsuits. They could easily build an in-car entertainment system as powerful as a iPad or android tablet if not more. In an ideal world, an in-car entertainment system has to be designed to be used so that it can be operated by a driver who should be focused on driving. So frequently certain features are disabled when the vehicle is in motion. Or at least designed so the driver can't watch a video. Small buttons, videos and lots of text are high liability risk.",
"It takes forever to qualify something in a car. A car can kill people and has to be made safe for 20 years, so every piece you put in has to prove that nothing can to wrong. So let's say you want to build something completely new into a car. First you need to develop it, possibly for years, then it may be very expensive to ensure that it is save, so high end cars only. Then when this is established, you can make it for cheaper (affordable) cars. Then when you buy a used one, even some more years pass. so maybe your multimedia center was invented 15 years ago..."
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8mx2ov | Why shouldn't you plug a power strip into another power strip? | I've seen so many things saying it makes it more likely to cause a fire, but nothing explaining why. EDIT: I appreciate the explanations, everyone, thanks! But I think some of you may have forgotten that this is /r/explainlikeimfive, not /r/explainlikeim25. | Technology | explainlikeimfive | {
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"The short answer is because outlets are only designed to draw so much current and adding power strips makes them more likely to draw a dangerous amount of current.",
"A powerstrip is a way of creating a parallel circuit: all devices you plug in get the same voltage. Since each device uses some amount of power, each will draw some current, which will all pass through the powerstrip wires. Since they're all plugged in parallel, all that current adds up. So the powerstrip tends to draw more current from the same outlet: it \"amplifies\" the possible current being drawn. It's the current that makes wires heat up, it's not difficult to see how this amplification effect can be dangerous. For example, suppose you have a 110 watt lightbulb plugged into a 110 volt outlet. It will draw 1 ampère of current from the outlet. Now plug a powerstrip with 5 outlets instead, and plug 5 lightbulbs in the powerstrip. Each lightbulb will still draw 1 A, so the powerstrip is now drawing 5 A from the outlet. Now replace one of the bulbs with another power strip with 5 bulbs. The first powerstrip is now drawing 4 A + 5 A = 9 A from the wall outlet. Most outlets and powerstrips aren't supposed to go above 10 A - 20 A, so you can see how easily this can become dangerous with devices that draw more power.",
"You absolutely can as long as you don't draw too much current from the source outlet, it's just that having more outlets connected to the same source makes it easier to exceed this limit. If the outlet can handle 10 Amps then plugging in even two 6 Amp devices will overload it, but you could safely have one hundred 0.1 Amp devices, using as many power strips as necessary to provide one hundred outlets. The trouble is if you plug 1 Amp devices into all those outlets you'll be ten times over the limit.",
"It is a falsely stated safety precautions. You _can_ quite safely line up as many power plug as you desire. But you have to be careful, all the devices that are plugged into your tree of power strips will draw current from one power outlet and therefore the current of all your devices will go through the cable of the first power strip. The problem is in this first strip, it has been designed to withstand a particular current, which is related to the amount of outlets it has. If you branch out to more outlets, you basically \"increase\" the amount of outlets of the first strip. To wrap up, the actual valid safety precaution would be: \"If you plug a power strip into another power strip, never connect more devices than you could using first power strip.\" And the answer why is to prevent the current to exceed limits. Exceeding current limits is how you'll get a electrical fire, which is undesirable, so that is _why_."
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8my3p0 | How many (technological) generations, roughly, are we away from being able to accurately simulate the real world, down to every molecule? | Technology | explainlikeimfive | {
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"Far enough that we don't even know if that's possible. If a computer even used a single bit to simulate each molecule and each bit was only a single molecule itself then the computer would be the size of the universe.",
"I think future simulations will be very similar to today's games. They won't be able to simulate molecular scale resolution and won't need to. Why? At a certain point, in terms of asymptotic limits, matter behaves the same way on the macro scale. That is to say, it wouldn't make a difference if you knew what an individual molecule is doing compared to a 1kg mass, or a 100 kg mass. For an Earth simulation, you can expect a lot of hack type solutions to make it plausible. Procedural algorithms will create the world around you in terms of people, animals, biology, and save that to memory in the form of less resource intensive calculations. In effect, only a certain radius in your field of vision, hearing and smell will be calculated and displayed to you in the Earth simulation. I don't think we are anywhere close to an effective simulation of Earth like this but I wouldn't say that it would be impossible by 2045 or 2050. I'm sure if you extrapolated out computer specifications by 2050 we would have a computer able of simulating Earth as if it were a video game. What you're asking about is pretty much impossible without some development in computer science which uses the previous model to emulate molecular resolution but not require a computer larger than the universe."
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8n6awk | Those who remember having to keep your TV tuned to Channel 3 to get a picture, what was the purpose of the other channels that just showed a screen of static/snow? | Technology | explainlikeimfive | {
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"The single channel 3 was the one video feed as supplied by the cable box which was decoding the cable signal. The cable box switched what channel it decoded but always delivered it to the television's channel 3. If instead of that you had an antenna connected to the television the channels would show all the openly broadcast programs (while they existed).",
"Channel 3 was chosen for most devices because it was rarely used for broadcast channels that would have caused interference otherwise. The other channels weren't used because there were more often broadcast signals on those.",
"It sounds as though you had cable. For those who watched with an antenna you changed the TV channels on the TV itself, not a cable box. It used those channels, at least those whose signals you could pick up.",
"Wow, this makes me feel old. Television stations broadcast their programming over the air. If you have a local station called Fox 10 or something like that it’s because at one point they probably sent their broadcast out on channel 10. If you hooked up an antenna to your television and turn the dial to the channel you want to watch (2, 3, 4, 12, etc) it wouldn’t be static/snow but instead it would be the program that was being broadcast. Once cable boxes, VCRs, and video game systems (and computers I guess) became popular they would commonly get the signal (sound and video) to your TV by sending it out in a similar way, often on channel 3 (though 2 and 4 were also common). You could plug the cable directly in to the same spot you would normally connect an antenna and it would pick up the signal from your device even if a television station was broadcasting on the same channel (because a direct connection was so much stronger than one picked up by an antenna). < no longer really ELI5 > You can still do this, though now everything is broadcast digitally so you need a television (or box of some sort) to decode the signal coming from the television studio. Everything you see now on old TVs is static/snow because no one is allowed to broadcast on those channels anymore (it was called VHF). Really old TVs would often have another dial that had UHF channels you could tune in, think of it like AM and FM radio. VHF channels were numbered 2-13 and UHF channels were numbered 14-83. Usually the VHF dial would have a channel marked 0 or U and when you set it there you could use the UHF dial to go higher.",
"You could get analog cable channels and antenna channels. You didn't have to have a cable box for basic cable channels in most cases as you could go straight from cable jack to TV and use the tvs built in analog tuner. All channels have a radio frequency so when you plug in your vcr, cable box etc and set to slider to channel 3 or 4 your device would display a picture using the selected frequency.",
"Well I assume that you got your channels through the air, with a smaller antenna and not a sat box and parabola or a cable box. A TV usually comes with a pre programmed channel selection. The TV doesn’t know if there’s something there or not. Your manufacturer probably went with this standardized way, because there’s usually airborne or public access, airborne channels of these frequencies. Now you come into the picture, you can usually scan the frequency range for channels. Imagine this like a radio. When scanning through the frequencies you only get channels with something on. Yes, you can manually go to FM 98.30 but you can’t really be sure that there’s something there, if not, you’ll just hear white noise. It’s not the radios fault that you don’t select frequencies with actual streaming on. So the purpose of those channels were simply to give you a wide selection. You could go to channel 387 if there was something on it. You just kept to channel 3 because there was something on it at your location, I remember mine being channel 1, 7 and 23. However you can actually program your TV channel selection, and make your channels in order after the initial scan. In Denmark where I am from, back in the early 00’s, we had maybe 4-5 public channels to choose from, that were mostly government funded. But I could still go out and invest in a cable or sat box and get a wide arrange of channels. Or I could be apart of a local collaboration, that supplied TV channels directly to my TV via cable, so they’d show on my regular channel selection."
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8n8pi6 | How come some vendors require my debit card pin but others do not? | Technology | explainlikeimfive | {
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"Your debit card has Visa (or another credit card company) backing it. Each transaction can be run as debit (processed by your bank directly, requires your PIN) or credit (processed through Visa, does not require your PIN). Processing as credit through Visa is to your advantage as the consumer. The consumer protections are much greater. If there is fraud or a dispute, you have a lot more power to get it fixed quickly. Vendors don't want you to choose this option, because when you do they have to pay Visa a transaction fee. This is why some shady Point of Sale systems will force debit even if you try to pick credit. You could complain to Visa about these places and they would probably be forced to fix it, but ain't nobody got time fo' dat. When you use debit, the money is literally pulled out of your account immediately without that intermediate \"credit stage\". This is a big deal, for example if you use it to check in at a hotel then the full amount of the hotel's holding amount will immediately be pulled out of your checking account. Versus the credit card approach where it is just a \"pre-authorization\" transaction that doesn't actually hit your account until they complete the posting.",
"You can spend up to £29.99 with contactless payment but will need to enter your pin for transactions of anything more. Or.. have i completely misunderstood.",
"Source: almost 10 years of card-specific processing. Your card issuer (the bank) has a preference on how they verify their cardholder, whether it's via PIN, signature, or not at all. This is primarily what drives the PIN request, but certain transactions require it regardless, such as ATMs. That's the simple answer. For more color: Prior to the advent of chip cards, transactions made with your PIN posted at the same time as they authorized due to the additional verification token, whereas transactions without it always had a lag between authorization and posting. However, chip cards muddy the waters. Sometimes, PIN transactions will travel along the signature networks, and vice versa; it depends a lot on issuer vs. Merchant network affiliation and a whole bunch of other industry nonsense. I could go on and on, but the long and short of it is that the PIN request is driven by your financial institution's preferences. That's it!",
"Similarly, how come when I use my credit card sometime I have to sign and other times I don't? I've had to sign and not sign at the same store before.",
"McDonalds is the only place where it's like SWIPE BAM. You're good. Other places are dial up, you pass a clip board (such as checking out of the airport or something) sign it, wait for the other copy to print out. I can go on and on"
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8n9aud | How are password managers more safe? | They don't seem that unhackable themselves to me but I could be wrong. | Technology | explainlikeimfive | {
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"Nothing's unhackable, but the idea is that it allows you to make more complex passwords for all the websites you use and have a secure place to put them, rather than something insecure like having a word doc with your passwords or writing them down on a piece of paper. Otherwise people tend to either re-use passwords across multiple sites or use very simple passwords. Password managers basically only require you to remember ONE password (preferably also complex) so that all your other ones can be a bunch of nonsense",
"They're naturally as safe as they are hackable, which is to say, provided you pick a good one that has good encryption, and most importantly, pick a very good master password, is nigh on impossible, or as much so as you can reasonably say for todays technology. Nothing is perfect after all. But taking the hacking of themselves out the equation, the point of them is they relieve you of the need to remember passwords, which itself prevents you falling into all the usual traps. Which is to say using a too-short, easy to remember password; using the same password across multiple websites; using barely-different variations on one password for different websites; writing passwords down and so on. You can create a password that checks all the boxes for making a password adequately safe, and just dedicate yourself to remembering that one password. Then, the manager can itself create a the rest of your day to day passwords, that each will also conform to the standards of safety that are required, but you don't have to remember them all. Someone who has direct access to the servers can decrypt passwords that aren't sufficiently secure in a surprisingly short length of time, seconds in some cases.",
"They encourage good password practices. Most people use the same password for all web sites, or they use a clever formula - \"AlternativeCorn\" is my basic password, but for Amazon I use \"AlternativeCornAmazon\" and for my bank I use \"AlternativeCornBank\" and so on. People think they're being clever and making secure passwords, but they are not. People do these bad things because good passwords are hard to memorize, and multiple good passwords are hard to memorize. In an ideal world, a person will use a unique, hard to guess password on every web site. That's why password managers are good. You only memorize one good password (the one for the manager). Then, for each web site, you use a different, unique password, which you save in the password manager. My password manager's password is \"AlternativeCorn\", but my Amazon password is now \"4t68fnBkeBNdet3!!kskt\". I don't have to memorize \"4t68...\" Many password managers will also type the password for you, so you don't have to type \"4t68...\" I've used a password manager for decades. I believe it has saved me from hacking attempts at least twice."
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8nbr7p | Why do people still use fax machines even though emailing documents is free and (debatably) easier? | Technology | explainlikeimfive | {
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"You cannot easily email something handwritten or that has signatures on it. It is possible by scanning, creating a pdf or jpg, then emailing that, but it is easier and more secure to just use a fax machine.",
"I work in organics, so we work with a lot of old timey farmers who don't do the internet. We always try to get people to email stuff, but every once in a while we get faxes from people who straight up don't have computers.",
"It is mostly a trust issue. You KNOW a fax is gonna work and that it tells you if it didn't. Most people don't have received receipts on emails and other features that would replace the fax. As many have stated, it APPEARS more secure, but when done correctly email is more secure for sure. Part of is it also a resistance to change and a matter of printing a document to sign it, to then scan it. Why not just fax it at that point?",
"Because your information can get stolen through email but not through fax. I was a mortgage banker for a couple years and we would never allow customers to email any important docs just fax because of this reason and that we could get sued for it if it came back to us.",
"Some interesting info in the thread... So, there's a couple of reasons that go hand-in-hand. Both of them boil down to \"It's hard to do a man-in-the-middle attack\" Previously, before telephony ran over IP, the regular phone network was a great way to send things like faxes, because it was all Layer One on the transport. No routers, no switches. Endpoints are the only ones that get a copy of the document, unlike email where each node along the route is an email server and each one gets a complete copy. Even if the email is encrypted, having a copy of it at an interstitial location provides a chance that it can be cracked. The second, and major reason, is that faxes are sent as *images* with a checksum and not *text* - it's preeeeetty much impossible to intercept and change a fax mid-flight in a man-in-the-middle attack. This is not true with email."
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8nfqw8 | How and when do they get those display cars into shopping malls that seemingly don't have doors big enough to get them in? | Technology | explainlikeimfive | {
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"Probably overnight or early morning. There are movable walls where cars can fit. Not sure if they slowly drove them in or if they are hitched by an ATV.",
"Shopping malls always have large doors somewhere as these are required for allowing large objects to enter both for promotional use and for occasional maintenance should it be necessary. You probably just haven't seen them, but trust me, they're there. In all likelihood, there's probably more than one door (probably one per 'wing', so as to avoid a car having to be driven across an entire mall to end up where it's supposed to go."
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8ng7kw | How does the Akinator work? | Technology | explainlikeimfive | {
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"I know that if it doesn't get it right it asks you type in the solution. Maybe that's how all the answers were fed to it except for the first 1,000 names the developers might have put in to get a prototype.",
"**Please read this entire message** --- Your submission has been removed for the following reason(s): ELI5 requires that you search before posting. There are absolutely no exceptions to this rule. Please see this [wiki entry]( URL_0 ) for more details. --- If you would like this removal reviewed, please read the [detailed rules]( URL_1 ) first. If you still feel the removal should be reviewed, please [message the moderators.]( URL_2 ?)"
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8ni1dw | How are 3D graphics rendered in order to get a cel-shaded or painted effect such as in Breath of the Wild? | So I know very little about 3D models and rendering, but seeing the actual character models from Breath of the Wild (they look very plastic/rubbery without whatever shading effect the game puts on them) made me wonder how the console actually takes the model and outputs it with the correct shading, and how one programs such an effect. Bonus question: There are certain scenes where characters are rendered as semi-transparent ghosts, how does the developer make sure that the inside/back of the model isn't visible through the front? | Technology | explainlikeimfive | {
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"Cel shading is a very simple effect: you just have to compute lighting as usual and then step it (ie: code something like \"if the surface is more than 50% lit it is considered 100% lit otherwise it is considered 25% lit). In practice you want more than one step (to keep specular highlights and the like) so you use a look up table, [like one of these]( URL_1 ). > how does the developer make sure that the inside/back of the model isn't visible through the front? Rendering translucent objects correctly is a nightmare, for this exact reason (and a few others). One way to make it work is to render translucent objects into the z-buffer first, then render them on screen normally with translucency enabled. (The Z-buffer is a data structure that store the distance of each pixel to the camera. it is used to know if a given pixel of a given object is occluded by something. By rendering the object into the z-buffer before rendering it on screen you ensure that pixels that are behind one of the other object's surface will be occluded correctly) Another technique is to render translucent objects normally (as opaque objects) but only every odd pixel. This is very cheap (much cheaper than real transparency) and looks very good on high-dpi devices (but only works if you want exactly 50% transparency). This isn't used in BotW but Mario [does it for silhouettes]( URL_0 ).",
"I'm not sure of the full details of the main question so I'll let someone else approach that but I can help with your bonus question. If you imagine a face of any object as having an arrow pointing up at a right angle this is called the normal. [Here is a cube]( URL_0 ) with face normals shown. There are 3 others not shown pointing in the opposite directions. When a game is rendering a scene it will check the direction of these normals compared to the direction the camera is facing. If the normal is point away along the same path of the camera then they are not drawn in screen and the ones that point towards the camera are drawn. This is known as back-face culling and will be what lets you have a transparent texture on an object without seeing it's back or inside.",
"Well the effect is exactly that, [cel shading]( URL_0 ). Basically you want to create outlines around objects and have flat areas of color instead of color gradients. I'm not sure how much you know or don't know so I'll just throw a mid-level explanation for it. If you need help with some of the terms or don't understand something, I can try to open it up with a bit more comprehensive explanation. For creating an outline around game models, you would render a depth map and a normal map. A large difference between two close points in either the depth or the normal map would indicate an edge. Here's a nice picture of the process: URL_1 One very easy way to achieve flat areas of color is to calculate lighting and color per-face rather than per pixel. For this, you'd use a normal for the face rather than for per vertex. Then you run all the lighting calculations in the vertex shader rather than the fragment shader and output a simple non-interpolated color to the fragment shader. This requires that faces have unique vertices rather than that faces share vertices, which is often done for optimization and to limit the chance of precision issues leading to gaps between faces. > There are certain scenes where characters are rendered as semi-transparent ghosts, how does the developer make sure that the inside/back of the model isn't visible through the front? They don't render parts with a normal pointing away from the camera. That is to say; The backside of a polygon is not rendered."
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8njijf | How do electronic signatures work? Anyone can just type a name as a signature, so how are they verified? | Technology | explainlikeimfive | {
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"It's basically just confirming that you are agreeing, and intend to legally confirm or agree to something. It should not be used as proof of identity. Usually with e-signatures you verify where it is coming from. If Joe Bloggs sends you something signed J Bloggs, he's going to look like a right twerp trying to argue in court that he didn't sign it, someone else did and he forwarded it on to you. And by right twerp, I mean he would be admitting to criminal fraud."
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8nm1hk | what’s the difference between Program Files and Program Files (x86)? | Technology | explainlikeimfive | {
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"Program Files stores 64-bit programs, Program Files (x86) stores 32-bit programs. The difference is that, amongst other things, the 64-bit programs can utilise more RAM and bus. Hence more efficient programs will be the ones in the non x86 file, especially in more modern, high end machines.",
"The Program Files (x86) folder contains applications which are based on a 32-bit architecture while the Program Files contains programs designed for the more modern 64-bit architecture. The number for the bit architecture refers to the width of the datapath and data registers of the processor; the wider datapath and data registers mean that the 64-bit architecture supports things like more memory and also increases the speed at which they can complete calculations. A 64-bit architecture processor can run programs designed for 32-bit processors, but a 32-bit processor cannot run 64-bit programs.",
"On 32-bit versions of Windows, \"Program Files\" is the default location for the installation of most application (non-system) software. On 64-bit versions of Windows, \"Program Files\" is the default location for the installation of most 64-bit non-system applications, and \"Program Files (x86) is the default location for the installation of most 32-bit non-system applications. There is nothing stopping a 64-bit program from being installed in the \"Program Files (x86)\" folder, nor is there anything stopping a 32-bit program from being installed in the \"Program Files\" folder. There's nothing special about the folders themselves. However, the environment variable %programfiles% resolves to \"Program Files\" on 32-bit applications running on 32-bit versions of Windows, \"Program Files (x86)\" on 32-bit applications running on 64-bit versions of Windows, and \"Program Files\" on 64-bit applications running on 64-bit versions of Windows. Failure to be mindful of this can result in bugs."
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8nr9tp | how do we sequence DNA? | How can we tell the order of something so small? is it just a big microscope with someone writing down the sequence? | Technology | explainlikeimfive | {
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"The first and most important method for DNA-sequencing was Sanger sequencing. I can try to explain it. A nucleic acid consists of four different nucleotides (G, T, C, A). They bind to each other and form a polymer (a chain). DNA consists of two such chains, which spin around each other and form a double-helix. In sequencing, the first step is to separate the two strands, by heating up the DNA-sample. We're left with a single-stranded DNA sequence. We then try to restore the double-helix, by creating a brand new strand, based on the template of the old strand. This is done using an enzyme called DNA-polymerase. It adds nucleotides to form a brand new strand. However, we don't just add the regular nucleotides. We add special \"defective\" nucleotides. The enzyme can't use these nucleotides, so the process stops, and we only get a half-finished new strand. The terminal \"defective nucleotide\" is color-marked so we can read which nucleotide it represents (A, G, C or T). We repeat the process for all nucleotides, and get many short half-finished new strands, each with different sizes and different terminal nucleotides. We put them in order, according to size, and read the terminal nucleotide. That gives us the sequence. I hope I made it understandable. It's much easier if you look at pictures actually, so you can see the structure of DNA."
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8nrem7 | How can people that have done surgery that puts metal in their body walk through metal detectors without setting then off? | Technology | explainlikeimfive | {
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"Metal detectors work by running electricity through a coil of wire, creating a magnetic field. When metal passes through, it distorts the magnetic field and the machine detects the change. The machines can be set to different sensitivity levels, so you need a stronger distortion to set it off. Some metals, such as titanium\\*, are less magnetic than others, so they'll distort the field to a small degree. And small pieces of metal, such as screws or rods, change the field much less than larger pieces, like joint replacements. Thirdly, your body works to dampen the magnetic field, so metal inside the body is weaker than a similar amount outside of the body. Source: I work with these things every day. \\* Popular belief is that titanium does not set of metal detectors, but this isn't true. I have a 10 ounce ball of pure titanium that I decided to test this with and it definitely sets them off."
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8nt97o | Why do wires have different rates and types of data transfer and how is this improved? | Technology | explainlikeimfive | {
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"Imagine you're talking to someone in a noisy room. You probably speak slowly and loudly. You might have to repeat yourself often. But in a quiet room you could speak quickly and quietly without repetition. The same is true for electromagnetic transmission of data. If there is a lot of interference from the outside world or other lines of data, it slows down the rate at which you can transmit. To get around this, wires tend to be shielded from the outside world and 'twisted' to avoid EM fields from aligning over long cable runs. The total resistance of the wire also plays a role. Any sort of real world system is going to have 'parasitics' - resistances, capacitances and inductances that arises from the imperfection of the physical world - that create undesirable filtering effects. This is difficult to describe in human-accessible terms, but it effectively 'rounds' the waveforms. What used to be a perfect [square wave]( URL_0 ) starts getting rounded corners. If those corners become rounded enough, you're no longer able to discern what the signal is."
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8nww1j | How does DRM work, and what made Denuvo so notoriously difficult to crack? | Technology | explainlikeimfive | {
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"DRM tries to assure that contract terms are obeyed, usually by only decoding the data for legitimate users. Most designs are add-ons, there is code that says \"this use is OK\", and then most of the code just relies on that. It's a single piece of code to hack or trick. Denuvo works differently, [as explained in this post]( URL_0 ). It made developers port there code to Denuvo's DRM-aware environment. This eliminated the \"one check and you're done\" approach to hacking."
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8nybtp | why do electron microscopes always show the image in black and white and not in color? | Technology | explainlikeimfive | {
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"Because it can't SEE colour. Imagine closing your eyes, and running your finger along an object, like say a telephone. You probe the shape and texture of the object with your finger, but your finger can't detect the colour, only the *form*. Electron microscopes are like that. They send an electron beam and scan the surface of the object, so it can only detect shape & texture, not colour.",
"Because electrons aren't detected in different wavelengths, like light is, in those microscopes. Electron wavelengths aren't as significant as their velocity in terms of energy, whereas light wavelengths are absolutely related to their energy. (Edit just in case: different colours are different light wavelengths)."
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8nycf0 | How does an inverted switch 12v dc to 110v ac? Where does the extra 98 volts come from? | Inverter*, darn autocorrect | Technology | explainlikeimfive | {
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"It reduces amps. Total electrical power is volts x amps, so at the same power, if one is reduced, the other increases.",
"Some of the inverters use a circuit called boost converter, a boost converter uses solid state switches (transistors or MOSFETs) to charge an inductor. When the power to the inductor is removed, the collapsing magnetic field generates a higher voltage. To make it AC some inverters use multiple boost circuits and switch between them, if you see most inverters on an oscilloscope you will see that the waveform is only three steps. Boost circuits can increase voltage but require hight current as input. Power (voltage times current) remains fairly constant between input and output.",
"Watts = volts x amps as you up the voltage the amps goes down 60 watt bulb = 120v x .5 amps or 60 watts = 12v x 5 amps",
"A set of electronic switches are used to convert the dc to ac. The ac then goes to a 12 to 110 volt step up transformer, which uses magnetic fields to multiply the voltage by a set amount."
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8nz61c | Can someone explain what the basic concept is behind multiplexing? | With relation to networks would be preferable. | Technology | explainlikeimfive | {
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"Me (Aaron) and my brother Bob are dating two sisters, Alice and Betty. We are all strange people, so me and Bob are each writing 100-page novels for our girlfriends. Each page that we write takes 2 days, and each page takes 2 days for Alice and Betty to read. We want to send the novels to them in the most efficient way possible, but because this is all fictional the post office can only mail a single one-page letter per day from our house to the girls' home. What options do we have? I could wait 200 days for Bob to write and send his whole novel, then I can send mine. But that makes Alice have to wait a really long time to receive her novel, and during the time that she's reading it Betty will just be sitting around idle, having finished her novel already. The whole thing takes 400 days. A better system might be for me and Bob to alternate mailing pages. As long as Alice and Betty are aware of the system, or we mark our pages with which one of us wrote them, this method still gets all the information where it needs to go but nobody is idling for nearly as long. It takes me 200 days to write my novel, and also 200 days to send it, and it takes Alice 200 days to read it. Bob and Betty also just need 200 days to write, send and read their novel. Instead of 400 total days, we just need (about) 200 total days. & nbsp; Often when sending data over a network, there are multiple senders and multiple receivers. The network can only transfer a limited amount of data per second. Since it takes time for the senders to generate messages and time for the receivers to process them, it's often most efficient to *multiplex* the messages by interleaving them into a single continuous stream, then *demultiplex* them at the receiving end.",
"[Multiplexing]( URL_0 ) is when you take 2 separate signals/streams of data/etc and squish them into a single one. Usually done in such a way that they're easy to separate later.",
"As far as I understand it, multiplexing depends on packetized protocols, and letting you put many streams of packets in a single stream by somehow identifying which packet belongs to which stream so that you later can \"demux\" them, for instance by tagging the packets or knowing the order they come in or by type."
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8nzdi8 | All the bits | What are 64-bit, 32-bit apps? What is the difference? What is the difference between 32 and 64 bit OS's?Also I have seen 8-bit music remixes, what sort of processing does the music go through? | Technology | explainlikeimfive | {
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"A bit is a binary digit, which can be a 0 or a 1. Eight bits is a byte. Computers store numbers for processing in \"registers\". \"64-bit computing\" means that the computer uses registers (and other parts of the system) that are 64 bits large, which means that each register can count up to about 18 quintillion. This means, for example, that such a computer could have a working memory of 18 quintillion bytes (each byte having a unique number called its \"address\"), about 16 million terabytes. Back in the early days of home computing, 8 bit computing was the norm. Each register was only 8 bits, or one byte, and so could only have 256 different values. That didn't mean it was impossible for the computer to work with larger numbers, but doing so meant using more than one register. This did impose a lot of restrictions: 64kB RAM, for example, or a character set of only 256 characters. \"8-bit music\" just means \"music of the sort you'd expect from an old-fashioned 8-bit computer\". At its most basic, \"music\" was generated by making a beep at a specific pitch -- and there were only 256 pitches you could choose from."
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8o09l8 | -What is data science? | Technology | explainlikeimfive | {
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"Data science is figuring out how to extract useful information from giant piles of data. You know how Netflix recommends movies? They know everything that you've watched and liked, and they know everything that everyone else has watched and liked, and they figure out what other people who like the same movies as you have watched and enjoyed that you haven't seen yet. That's data science. Similarly with Amazon. They look at everything that everyone buys and then recommend more things that you might want to buy. How do they do it? Basically it's lots of math. A related name is ”big data\". Up until recently we didn't have enough computer power to make correlations across such giant piles of data about so many people, but now we do.",
"Let's say you're Santa Claus, and you want to give the best possible gifts to everyone. Sadly, the company that makes the gifts is erratic, and didn't give you a list of what they created this year. You have a large stash of gifts in your warehouse, and it's really messy. You call upon the elves \\(Our Data Scientists\\) for help. Since they have no idea about what's in the warehouse, they start\\*\\* exploring. They start with the most basic details, like quantity, size etc. and take notes. Then they can group the gifts by observing patterns like toys, accessories, same destination city, are they naughty/nice etc. Finally, they give you a nice comprehensible list that you can use to effectively deliver presents. Now lets say you got feedback about the gifts that you sent. It's mostly nice, of course, but some of them didn't like what they got. You ask your elves to do something about it. The elves now again search among the gifts, if there's a set of gifts that a group of kids always hate. They try to find such \"patterns\" or \"correlations\" and then give you reports on what they find. Based on these patterns, you could now \"predict\" which gifts are more likable. This is a good part of a Data Scientist's life."
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8o1a9k | USB 3.1 & the difference using it with usb type A or C. | Technology | explainlikeimfive | {
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"text": [
"USB A, B, C, mini, micro are about the the shape of the plug: URL_0 . Type C is unique compared to all previous ones in that both ends of the cable are the same, and you can turn it upside down. USB 1.0, 1.1, 2.0, 3.0, 3.1, 3.2 are mostly about the data transfer speed, but also how much power they can deliver. Devices on both ends negotiate to use the fastest speed they both can handle. You *usually* get at least USB 3.1 or 3.2 speeds if the device has a type C plug. Some devices also support transferring various video signals (HDMI, DVI, displayport) over the same type C cable at the same time as USB data."
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8o1h79 | what is the purpose of the basketball looking things on power lines | Technology | explainlikeimfive | {
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"text": [
"To my understanding, it's just to make them more visible to low flying aircraft. Especially near and around airports.",
"Balisors are less common around airports (where air traffic is tightly controlled) than in the countryside where low-flying planes are likely (if not common) for crop-dusting, police, state natural resource departments. They can also be visible at night, read here: URL_0",
"They are there to make them more visible to aircraft. Often they are used near airports but they can be used in other places too. Many hospitals have heliports, so you will see them near hospitals often. Another place they are used are where power lines cross canyons. Helicopters often fly low in canyons as part of rescue operations or training. Even at slow speed a power line is hard to see from the air, and a chopper encountering power lines would make for a bad day. Military aircraft often practice low level maneuvers in canyons so these balls are used. An example of what can go wrong when a military aircraft encounters a wire in a canyon can be evidenced by this [event in Italy]( URL_1 ). Often helicopters are fitted with [cable cutters for such encounters]( URL_0 ). But a pilot hopes to never have to rely on them."
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"https://www.nytimes.com/1998/02/04/world/20-die-in-italy-as-us-jet-cuts-a-ski-lift-cable.html"
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8o4axa | How does Winrar get companies to pay for it when they could do exactly what we are doing? | Technology | explainlikeimfive | {
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"text": [
"Why does anyone still use WinRAR when we could all just use 7-zip?",
"WinRAR's license specifically allows you to keep trying it as long as you're merely an individual; however, if you're a company, you have to buy a license or you risk huge liability if caught, and since the software is so consistent in nagging, nobody could say the company didn't know they were infringing. Companies have to license all sorts of software, so it's easier in many cases to just get it over with and expense that through the well-established processes than run the risk of going out of business over a lawsuit about a single small piece of software.",
"Companies can't do what we do because it's a liability. They'd technically be breaking copyright/plagiarism laws, and no company wants to risk a law suit."
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8o6nk7 | How can a car's performance be increased by OTA updates? | I was reading about Tesla improving acceleration and braking on some of their models through software updates. How can that be done? I mean I get how performance can be limited, but how can it be increased without any changes in hardware? | Technology | explainlikeimfive | {
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"It means that, for example, the brakes are computer\\-controlled and the computer is holding the brake's capability back intentionally. You press the brake pedal, that signal goes into a computer, that computer knows how hard the brake's hardware can ACTUALLY squeeze, then sends a limited signal based on what it's set to do. The brakes and other parts are possibly setup this way because ideal performance may require a lot of number crunching, and number crunching may take data from a LOT of cars. So they built a car they could adjust later after they find out how thousands and thousands actually perform on the road, not a lab.",
"If the hardware is being used suboptimally, then changing how the computer controls it can improve how it performs. For example, in order to brake effectively, you want to avoid skidding. If an engineer figured out a different way to operate the brakes to reduce skidding, that would improve how well they work.",
"Elon Musk mentioned one time how an update optimized how the front and back motors worked together to increase acceleration.",
"> I mean I get how performance can be limited, but how can it be increased without any changes in hardware? Simple: They shipped with limitations and the updates reduce or remove them.",
"All modern cars ( not just electric cars like Teslas) are controlled by a computer. This computer manages lots of things but most importantly the timing and fuel ratios. If you have the right software and proper cables you too can modify the values stored in your car's engine management computer and improve its performance. (Now of course this could end up causing you to fail safety and emissions testing in certain US states). Tesla doesn't have to worry about that since their electric cars don't have any regulated emissions.",
"Think about it this way; The whole car is controlled by electronics. Small computers with a specific software that tells it how to react to very specific situations. If t was just a matter of always spinning up a motor as fast as possible, the software would be kind of easy to write. But. Now it’s a matter of always spinning it up as fast as possible, and at the same taking into account that you don’t want the wheels to loose grip and start spinning. So. Acceleration will have to take into account information coming from the sensors that detect spinning. And if you measure the power consumes by the motors, you can pretty reliably predict when the anti spin will detect a short while before it actually happens. And thus prepare for the spin. Which requires that you further advance the software that controls acceleration. You probably see where I’m going with this. The software that controls acceleration is advanced. Tested. Rewritten. Tested again. And so on. And I’m not even close to describing the basic features. I still haven’t covered how acceleration should go faster or slower depending on how you use the gas pedal. Or how you make sure the motors live their expected service life. Or, you know, a lot of other things. It’s the same with the brakes. That software is also taking a lot of shit into account. Electrical cars often use *regeneration* as a braking method. It means that if you stop giving the motors power when the car is moving, you can instead use the motor to *generate* power. And by doing so, the motors will slow the car down. And. Of course, conventional brakes too. If I understood the articles on the subject correctly, Tesla has changed how the regeneration cooperates with the conventional brakes. They figured out a way to make the braking more efficient in a lot of situations by thinking further on how to make two separate braking systems cooperate. This kind of thing happens on all other cars too. The difference is that Tesla has a communication link to their cars they can use at any time while other manufacturers rely on you visiting a dealer yearly to get updates. Tesla tells everyone what they are doing while the other brands do it silently. That is really the mayor difference here. (But. You know. You can totally rest assured that Tesla updates things without telling too. While they are at it.)"
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8o6sew | Why do electronics stop working after they are submerged by water? | I could understand if they have power running through them, but what about electronics that are powered off completely? | Technology | explainlikeimfive | {
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"The immediate answer is conductivity. Water is extremely conductive to electricity. If water is connecting two electrical components, electricity will flow between them. If it's connecting two components that aren't designed to connect, that causes errors or possibly even permenant damage. Water can also permenantly damage some electronic parts on a physical level, like screens, batteries, buttons, etc. If something isn't designed to be completely submerged in water, it probably won't work again until it's dried. Even then, residual moisuture can cause malfunctions. Speakers are a good example: water in between the diaphram and the casing can cause it to lose the ability to transmit sound clearly. If you've dunked your phone in water, you might be able to see moisuture droplets beneath the lens of the camera, ruining photos more or less permenantly. Water also causes quick corrosion to ferrous metals, causing those components to wear out or lose their conductivity.",
"If they are powered off and you get them out quickly and let them dry completely, they will often be fine. But drying them out completely isn't trivial.",
"A few thoughts... Water is conductive, so even if the device is powered off, where water bridges the contacts of the battery and connects it to other places on the circuit, you can now be potentially dumping a whole batteries worth of power into small components that cannot handle it. Even without a battery, it also doesn't mean the circuit is safe however, as components like capacitors can hold an electrical charge for significant lengths of time, and again if that current gets to the wrong point there can be serious damage. Water can also damage some components by just being there - components that rely on precision spacing, movement or contact (thing the layers of a touch screen maybe, or the moving parts of an accelerometer) can be damaged if a physical item breaches this. Water is also corrosive to metals, and due to the tiny sizes of components and circuit board traces used in consumer electronics, this can take hold quickly and destructively. A protected (painted) steel beam may take decades to rust to the point of worry, but a tiny trace a fraction of a millimeter thick won't last long. Water is also rarely pure, but comes with a wide and varied collection of other materials dissolved in it - an obvious one being saltwater, which is hugely corrosive (far more than pure water) and will dry out leaving deposits of salt behind, which will continue to corrode and damage the circuitry."
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8o6x60 | Why don’t rockets launched in to space hit any of the junk circling earth’s atmosphere? | Technology | explainlikeimfive | {
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"There are a few main reasons. First, the people launching the rockets try to avoid what they know is up there. The second factor is that space is very large and there just isn't that much stuff up there in the first place. If I dropped you somewhere in the Pacific Ocean at random would you really be afraid of hitting a plastic bag? Sure, there are a lot floating around out there, but the ocean is *huge* and they just aren't that common in comparison. Now consider that space has three dimensions and the ocean surface only has two.",
"They do hit space debris. The Space Shuttle, Hubble Telescope and the ISS have all been hit by debris. URL_0 While we can track pieces about the size of a grapefruit using radar - there is an awful lot of stuff we can't track. This set to become a much bigger problem in future and collecting space junk is a problem that a lot of people are trying to solve."
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8o8mbt | Why are the pieces in a torrent downloaded in random order rather than sequential? | Technology | explainlikeimfive | {
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"Torrents split up the files into smaller numbered chunks. When you download the torrent, you need people who have the pieces to upload to you. Torrenting works faster when everyone downloading has different parts of the torrent, because then you can upload that portion of the torrent too, meaning the file spreads outwards like a web or ripple. If everyone’s client tried to download sequentially, it would form a bottle neck as everyone else waits to download the same portion, and then upload that same portion to everyone else... causing a wedge-like formation of file dispersion.",
"Let's say you have 3 people. A has the whole file. B & C have none of it. If B & C download sequentially, A must give each of them a complete copy of the file because B already has everything C does. If B gets the first half & C gets the second half, A can only send out *one copy* of the entire file & let B+C share between themselves. As you add more people to the torrent, the effect gets magnified.",
"Follow up question, based on the other excellent responses: You have to have a non-sequential upload, to maximise the speed at which it can be distributed and reduce the risk that the seeder might disappear and leave everyone without their file. That makes sense. But is it actually *random*, or is there some behind-the-scenes optimisation to make it an optimal distribution of packets? If it's optimised, how does that work?",
"This website has a great visualization of how bittorrent works: URL_0",
"Imagine that are 100 pieces. There are ten people getting it. The blocks are in order. Something happens to the seeder. It stops sending packets. All ten people have blocks 1-30. Nobody has a complete copy. Now imagine that it’s random order. Now it’s very likely that among the ten downloaders, they have enough to talk to each other and everyone can get a complete copy. They all still have 30% of the download, but it’s not the same 30%. Now, imagine that the seeder was always sending out the blocks that it has sent out the least that the receiver didnt already have. That makes it almost certain that a full copy will exist if the seeder goes down."
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8o9f42 | Why are there no electric planes flying commercially yet? | Technology | explainlikeimfive | {
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"Batteries are heavy. That's the answer. It's just like cars in a way. Gasoline powered cars have longer range, quicker refueling, time-tested engineering, and wide adoption working in their favor. Electrics are still expensive, limited, and relatively new. Electric planes exist, but they suffer from range and payload issues. Batteries are heavy, recharging would delay airplane turnaround at airports, the technology is less tested, and the infrastructure isn't there."
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8oblax | How the random() function works in C++. | This one has been troubling for me sometime. I'm not able to figure out how to generate a random number without using the random() function. Or even how the random() function was coded. | Technology | explainlikeimfive | {
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"C++ and other languages use a simple mathematical mechanism called a [Linear Congruential Generator]( URL_0 ). You start with some number called a \"seed\", and then each time you call random() it multiplies the current number by some constant A, adds another constant number C, divides by a third constant M and keeps the remainder. The remainder is the new random number. The function srandom loads the seed. Usually you use the current time as the seed, to make sure you don't get the same sequence of random numbers each time you run the program. Note that this is a very basic and not secure random number generator.",
"It's a pseudo random number generator. It starts with a \"seed\" value, and when you call random it runs that seed through some operations to generate a new number that for most intents and purposes is unrelated to the seed. That value is then used as the seed for the next time you call it. It's not truly random because if you start with the same seed, it will always give you the same sequence of numbers. So often you use some system value that is unlikely to be the same between multiple runs of the program as the seed, such as the system time. If you need truly random numbers (e.g. for cryptography) you need to use special hardware features that measure a physical source of randomness."
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8od8or | How do landlines call mobile numbers? | Technology | explainlikeimfive | {
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"To explain how this works we should first address an evident misconception about mobile phones: They do not communicate directly with each other or with satellites. They communicate with cell towers on the ground, typically within about 5 miles. The connection is then transferred to its destination over conventional cables. So if you are calling a cell phone more than 5 miles away from your own cell phone it goes: Your phone, cell tower, cable to other cell tower, cell tower to destination phone. As you can see a land line phone just routes the call to the appropriate cell tower to reach your mobile phone.",
"Signal goes from your phone to the tower, the cell tower contacts the automatic phone switching system and routes your call to the approach switch, your call keeps going through switches until it reaches the switch to make your final connection. Then the call is switched to the land line, routes down the line where the phone rings. This all happens very quickly."
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8odlir | Why are all new games being announced right before E3 and not at E3? | Technology | explainlikeimfive | {
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"This draws people into their E3 events. If there’s hype around a developers new game they will be more inclined to watch their presentation than if there’s just the promise of new games. Kind of like why stores have signs advertising sales to draw people in rather than relying on people coming in on their own."
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8ohexc | Are modern day CPU speeds being limited by physical dimensions? | Hypothetically, would CPU manufacturers be able to make insanely fast processors if they weren't making them fit in to conventional sockets. Like could they make one the size of your dining room table that could process information at insane rates. From my basic understanding it has to with the number of transistors in a CPU \(as in more transistors = more GHz\). Assuming that we were able to cool it sufficiently and there was some type of motherboard that could support it. | Technology | explainlikeimfive | {
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"Yes the are limited by physical dimension. For example the speed of light is 299 792 458 m / s. If you run a processor at 4 GHz the light will travel 299 792 458 /(4*10^9)=0.075 m=7.5 cm during a clock cycle. A signal in a processor travel at lover speed the light so travel speed for a signal is important > (as in more transistors = more GHz) This is incorrect. The speed depend more on the size of the transistor and how you build a pipeline. The size is relevant because the speed a transistor can switch at in a digital network depend on the capacitance of the load after and the current trough it. So smaller transistor and conductor result in less capacitance and faster possible speed. The pipeline is how you bild the CPU. A Pentium 4 used a deep pipeline so a single instruction had 31-stages. The intel core 2 that followed it had 12-14 stages. The more stages you have the less you do on each stage and the more is dedicated to store information to the next stage. There is also problem with information that you need in one instruction might not be calculated yet and that prediction of branches are incorrect. The result was that the change from Pentium 4 to core 2 was that the frequency was close to halved but the performance was a lot higher. To have higher frequency the number of transistors are not important what you care about is the ability to cool the system and the size of the transistors. The amount of transistor a processor have will determine what it can do and the time in cycles it take to preform a operation. The way to have higher frequency processor is increased cooling and low temperature. You can overclock the high frequency if the cpu is cooled with liquid nitrogen.",
"One important consideration for CPU design is that speed of light limits the design. Speed of light tells you how long you have to wait until one part of the CPU can affect the other part. If you had table-sized CPU, then one end of that table would take about 3 nanoseconds to be able to have any influence on the opposite side of that table. If you need to send request to the other side of the table and back, that's about 6 nanoseconds. This means, physics itself would prevent you from doing more than 1.6 billion operations per second if they dependent on far away parts exchanging information. If you have self-contained smaller chips on this table-sized chip which can mostly do logic using only nearby parts... Well, that design is called multi-core design. Each self-contained part is called a core. Modern computers actually do pack multiple cores. However, even if you add tons of cores, there are some tasks where having ton of cores just doesn't help you at all. However, one such case where multi-core design frequently provides massive boost is graphics. And whaddya know, graphics card, that huge plate, basically consists of hundreds or thousands of cores which all just want to do simple math.",
"First answer, so sorry if I'm a little overboard on detail! First things first, the **clock speed** of a processor is nothing to do with how many transistors are in that processor; you can speed older processors up within reason, or slow new processors down. Increasing clock speed means more heat is generated, which is often a bottleneck in modern CPUs - hence the rise of multi-core processors. It's **extremely important** to note that very often the bottleneck is not how fast the CPU runs, but how fast **memory can retrieve information**. I'll go into this more in a moment. CPUs follow a very common model when they execute instructions, called the **fetch-decode-execute cycle**. (**side note:** an *instruction* is a machine code number that translates to something like \"move the value of register A to register B\", or \"load the value in memory at address 1024 into register A\") The fetch-decode-execute cycle does what it says on the tin. Fetch an instruction from memory, decode it, and then execute it! A simple processor will fetch one instruction, decode it, and then execute it, **doing nothing else while this happens.** Now, that model can be sped up by turning up the clock speed, until you hit a wall: **main memory (RAM) can't keep up with the speed at which data is being requested.** It usually takes quite a few clock cycles for main memory to get the requested data, due to the multi-gigabyte sizes we're working with today. In the context of modern applications, that delay *isn't acceptable any more.* We've all seen those graphs of how fast clock speeds have gone up since the 60s - exponentially! What those graphs don't show is that **memory access times have barely improved since then!** We simply haven't found many solutions to straight up increasing access time in memory, unfortunately. Now, modern CPUs get around this in all sorts of clever ways - one way is to use **cache memory** - which is like special RAM which sits in-between the CPU and main memory. It's *super* fast, but as a tradeoff is small in capacity. Extremely clever methods (often rooted in maths) are used by the CPU to work out what data **is going to be accessed, and put it in cache before it's even needed!** People can and do spend their entire careers working on cache memory, and some of Computer Science's hardest problems are related to it. Another way of improving straight-up performance is **pipelining**. What this does is conceptually simple - split the Fetch-Decode-Execute cycle into **multiple stages** - e.g. one for fetch, one for decode and one for execute. Since those 3 steps are independent, you can **fetch an instruction while the previous one is being executed!** This leads to absolutely massive speedups in computation within a CPU, and is often closely tied to cache memory too. **tl;dr:** the bottleneck with modern computers is often memory access times, **not clock speed**! This can be reduced with cache memory and pipelining."
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8oif7p | Why does a lot of retro tech have a “thousand” at the end of their names? | Technology | explainlikeimfive | {
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"To make the name sound more futuristic and high-tech. That the technological breakthrough in the product was so significant that it was worthy of bumping up the version to some multiple of 1000. Alternatively, in the decades before the turn of millennium, adding 2000 to something sometimes implied it incorporated technology ahead of its time that would fit in with the latest and greatest of the future.",
"This is a post WW2 phenomena. Tech was becoming a thing. Computers, atomics, etc Planned obsolescence required new, better model names, 1, 2, 3... At some point the univac 4 needed to be better just by the sound. Univac 400 vs the IBM 401. Jump a head to the nth degree. The univac 9000 or the OS X for that matter. And never more than 1000s because univac 12000 doesn't roll off the tongue as well. It's a marketing trope that bigger numbers sound betterer when implying power. There was a trend before the cold war got intense to add \"nukey\" words to products/places. Atomic Cafe, Hydrogen Jukebox. This is passé."
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8oj0ux | What is "embrace, extend, extinguish"? I know it's a thing that Microsoft does involving killing... something (?), and I've read both the Wikipedia description and the previousexplanation but I'm still totally lost. | Technology | explainlikeimfive | {
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"Microsoft has used this approach in the browser space as follows. Bring out a browser that **embraces** the standard used in other browsers. Thus sites that work in other browsers also work in Microsoft's. Then add some new features, which are highly dependent on operating system interfaces which you don't make public. These new features **extend** the standard, and allow websites that use them to have more features, but only when viewed with the Microsoft browser. The effect on users is that when they go to some sites with another browser, they don't work, with a message that says \"This site requires Microsoft browser version X or above.\" Thus even a user who prefers another browser has to have two browsers on their machine, and one of them must be Microsoft's. Over time, having two browsers is too much work, and more and more sites only work with Microsoft's, and eventually the other players are **extinguished**.",
"If you don't like a competing product, make yours compatible, then make yours better so people switch to it, then cancel it so people have to switch to your other product."
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8oji5s | How does an updater update itself? | Technology | explainlikeimfive | {
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"text": [
"Anything that is currently running can't be updated immediately because files that are in-use are locked. An updater, when encountering files that are in-use (including the updater itself) will place the new files in a temporary location, along with an instruction for the OS to overwrite the now-running files the next time there is a reboot, or you bounce the program. So if you've ever wondered why some updates require a reboot and some do not, it's because those files are in use and need a reboot to not be in-use."
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8okvv1 | What's the big deal about Apple depreciating OpenGL support in favor of Metal? | Technology | explainlikeimfive | {
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"The part of your computer that draws the pictures doesn't speak the same language as you. In order to make it draw pictures, you need to talk to it in a language it understands. OpenGL is a \"high level API\" for the drawing bit of your computer, which is kind of like you having cards with pictures on it that you wave around to be understood when you meet people that don't speak the same language as you. This works fine, and the drawing bit understands what you want it to draw, and everything is good. Metal is a \"low level API\" for the drawing bit, which is more like learning basic words and phrases in the language it speaks, until you become conversational. Either way, the drawing bit understands what you want it to draw, but by speaking its language, it has a better understanding of what you want from it, which mages it faster, and makes the drawings potentially better. The switch then, is to get more out of the drawing parts of computers. By deprecating OpenGL they're saying \"look everyone, you're gonna have to stop waving your picture cards around and start learning the language\", so that they can get (hopefully) beer drawings out of the software. Quite why Apple care about good drawings given that the best use for Apple products in gaming is using the MacBook as a mouse mat, but that's a different conversation. The big deal is that Metal is proprietary, so people have to pay for it, and OpenGL is free, so it's another thing in the long list of ways Apple is effectively charging people to make things run on their computers. Source: am programmer, amateur game dev, and all round computer nerd"
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8omgtf | Why does nothing work with 3G or even 4G sometimes when years ago it would have been more than enough? | Technology | explainlikeimfive | {
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"Cell phone companies have a limited amount of frequencies (bandwidth) available. LTE uses this available bandwidth more efficiently (more users all getting higher speeds). As more and more people have gotten LTE-capable phones, the cell companies have responded by shifting bandwidth away from 3G and more to LTE to better meet demand, but this does mean that less bandwidth is available for those still using 3G or non-LTE 4G. Of course, there's also an effect that pages simply take up more bandwidth than they used to, simply because average available speeds are constantly increasing."
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8oo00h | What is color sampling? when someone throws ratios like 4:4:4 or 4:2:2 what do those corresponding numbers mean. How does this relate to the design of a CMOS sensor? | Technology | explainlikeimfive | {
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"4:4:4 means that every pixel has an independently defined brightness and colour. 4:2:2 means that every pixel has its own brightness, but adjoining pairs of pixels share the same colour. Similarly there's 4:1:1 where rows of four pixels share a colour and 4:2:0 where two-by-two blocks of pixels share a colour. These schemes allow video to be encoded with fewer bits and work well because our eyes can't see detail in colour as well as we can in monochrome. An 8 megapixel camera will have 4 million green sensors, 2 million red sensors and 2 millions blue sensors. Typically (with Bayer pattern) groups of four pixels are arranged like this: G B R G This is a close match for 4:2:0 colour sampling since colour is only fully defined for groups of four pixels. Note that an 8 megapixel camera only has 8 million pixels in all whereas an 8 megapixel display, e.g., a 4K TV, has 24 million sub-pixels: 8 million red, 8 million green and 8 million blue."
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8optrj | What's the difference between a camera sensor taking a picture or recording a movie? | For example how are the camera megapixels not related to the recording quality of a movie? If a camera can record at 120fps, why can´t we take 120 pictures per second? | Technology | explainlikeimfive | {
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"> how are the camera megapixels not related to the recording quality of a movie? They are related. Most cameras use sensors with more pixels than the video format, but that is not always the case. Expensive broadcast video cameras often have just 2 megapixels. > If a camera can record at 120fps, why can´t we take 120 pictures per second? You are taking 120 pictures per second when you record video at 120 fps. They just happen to be in a single file. They can easily be extracted. I think what you're really asking is what are the differences between a still formats and video formats. Video formats are usually 16x9 and around 2 megapixel for HD or 8 megapixel for 4K, while still pictures can be almost any size or aspect ratio (even though most still cameras use a limited set of sizes). One reason that you can't take 20 megapixel stills at 120 fps is a hardware limitation. It can't process and store the pictures fast enough. Another reason is that still photos need more time to prepare before exposing the image because auto-focus and exposure adjustment is more precise in still mode than in video mode. A third reason is that it would fill memory very quickly. It isn't a feature people have been clamoring for."
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8oq7ki | How does Google keep their map updated? | They always seem to have all the roads and construction updated immediately. How? | Technology | explainlikeimfive | {
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"text": [
"There are a lot of sources that Google can pull from, and obviously they don't really disclose all of them. They own Waze so a lot of the closure data is sourced from the users submitting real time info there. Users running Maps on mobile devices or in Android Auto that are still opted in to data sharing will also allow Maps to gather real time data about detours, traffic issues, and the like. Before the [Maps vandalism incident]( URL_0 ) there was a system called Map Maker where trusted users could directly edit the map itself in near real time. With high enough trust levels changes were published instantly. Old trusted users from that system still have some level of ability to publish changes quicker in the updated Maps interface. There are also the Local Guides program still in place where again trusted users can submit info. Changes to roads and boundaries are handled by a much smaller team now, but with better community hive mind input, they can spend time validating road updates and not as much time dealing with correcting point of interest edits like hours, phone numbers, websites, and closed businesses that all rely on community consensus to publish to the map more or less automatically."
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"text_urls": [
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8oqgtr | Why electric cars aren’t solar powered? | Technology | explainlikeimfive | {
"a_id": [
"e05a9pa"
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"text": [
"Some do have solar panels, such as the [Fisker Karma]( URL_0 ). Most manufacturers have released designs or concepts with solar panels (Tesla, Ford on the C-Max, BMW, Toyota). Quite simply, a panel small enough to fit on a car doesn't collect enough energy to power a car. A whole roof is only good for 300-400 watts of energy in full sunlight. A P65D Tesla (for example) has a 65,000 watt-hour battery. Considering 10 hours of sunlight per day, you'd need the better part of a month to charge the battery once.."
],
"score": [
4
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"http://st.motortrend.com/uploads/sites/5/2011/02/2012-fisker-karma-top-down-view.jpg"
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|
8otz5z | What exactly is a RAW image (or video file) and how does it allow extensive digital color processing when it's so grayish? | Technology | explainlikeimfive | {
"a_id": [
"e062nm9",
"e06d8uh"
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"text": [
"it's the raw data from the image sensor; there's way more data than you'd get with a JPEG or TIFF, but it hasn't been cleaned up for presentation. It has the advantage that all the extra data hasn't been thrown out yet, so you can set your own white balance wherever you want, because all the metering data is still there. So basically, it's not grayish; whatever software you're using to display it is just doing a bad job of interpreting it.",
"Photos and videos can get pretty huge, many formats, like JPEG and MPEG, use lossy compression to save space, with a slight but usually unnoticeable loss of quality. A RAW format isn't having any of that, it wants maximum quality, no matter how huge the files get. You can always compress and process later, keeping your RAW file around as a high-quality master. Your eye has slightly different sensitivities to light and color than a photosensor does, in particular, we are more sensitive to change in color than change in hue. A RAW format stores the image exactly how the photosensor sees it and lets you process to make it nice for humans afterward. Also, every camera has a slightly different photosensor. Good (i.e. not free) photo processing software will often recognize various camera makes and apply the right kind of processing. If your camera is not on the list, or if you are using cheaper software, the generic settings might not be right for your particular camera."
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9,
3
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|
8ouesk | How software and hardware interact? | How these two interact? How does a software know which buttons did i press? And, How a bunch of codes which do not have any physical body or shapes makes changes and movement into a hardware? | Technology | explainlikeimfive | {
"a_id": [
"e066wfx"
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"text": [
"Let’s take your keyboard as an example. You press a key on your keyboard. This completes an electric circuit. There is a small microchip embedded in your keyboard that is loaded with what we generally call “firmware” that suddenly notices “hey, electricity is flowing through the ‘F’ key circuit!” (because it is literally wired as part of said circuit). It then sends a signal up the keyboard wire to your computer. Your computer then has a bit of code called a “driver” that interprets that signal and determines that it means the “F” key was pressed. It then sends a signal to your text editor program saying so, which then uses that knowledge to print a “F” on the screen. It also works in the opposite order as well, with the program sending a signal to the driver, which sends one to the firmware, which opens or closes an electronic circuit to, say, turn a light on or off, or turn on/off an electric motor."
],
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9
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8ouqgg | Why there's almost no researches trying to create new devices which could allow us to explore the bottom of the ocean? | Technology | explainlikeimfive | {
"a_id": [
"e068va3",
"e068yj1"
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"text": [
"Your statement that no one is trying is false. I think most of the limitation keeping us off the sea floor currently is technological, or more specifically materials science limitations. We don't have anything to make a submersible out of that can both withstand the pressures experienced at the bottom of the ocean and also be large enough to house researchers and their equipment.",
"For something to be done it has to be profitable. For us to use billions of dollars and thousands of man hours to create a technology, we have to be able to profit from that technology. Who is going to fund a project that’s not given anything back? So now the question is, what can we possible find on the bottom of the ocean that can make this whole thing profitable. You can probably answer that better than me and I’m not trying to argue against it. But as an economist, unless there’s a gain, it won’t be done. It’s the same deal with the moon missions. We won’t send anymore people to the moon, simply because it’ll be a waste of time and the costs will be greater than the Benefit."
],
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4,
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8ow573 | Why was videography and photography first invented in black and white and not straight into color? How was color added later on? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Black and white film is a bunch of [silver salt]( URL_0 ) crystals suspended in gel. Exposed to light, the silver salt reacts, and (once you add developer chemicals) becomes translucent or opaque. Color information isn't stored, only intensity of light. Obviously you can't get color photos unless color information it stored somehow in the film. I don't know what chemicals are suspended in the gel to react specifically to red, green, and blue light, but I imagine the process is similar, and because it was more complicated, it came later. One technique that existed before color film was to take 3 black and white photos through red, green, and blue filters (so the film would only record the intensity of the red, green, and blue lights separately). Colored light could then be applied to each of the black and white photos in order to [reconstruct the color image]( URL_1 ).",
"Black and white photography uses only one layer of film coated in a chemical that reacts when exposed to light. This reaction gives a greyscale image, that we discribe as a black and white photograph. Colour photography uses multiple layers of film, each layer reacts when exposed to light of a certain wavelength , that we see as colors. In 1855, researchers demonstrated that three colours, red, green and blue could be combined in various ways to produce all shades of visible colour. So tradition colour photography used three layers of reactive film, that generated red, green and blue images. They were combined to produce full - colour images. This colour process is simply more complex that simple single - layer black and white photography, more complex to invent and to use. For many decades, the cost and complexity prevented its use in all except the most costly and elaborate applications.",
"Photographic film are made up of chemicals that react when hit by light. You then have to develop the image in a chemical process to create a stable image. If black and whit film is it simpel silver halide crystals that is exposed and they react with light of all colors. If an singe strip color film you have to have multiple chemicals in the film that each only reacts with one color of light and then be able to develop it and create multiple colors. To find the chemicals and a way to develop it was not easy. That was not a simple thing to do and it took close to 100 years from the first silver based black and white photos start to emerge in the 1830 until a single strip color film was introduced in 1935 but is was expensive so black and whit continue to stay dominant into the 1950-60 There was a way to create color image before that taking 3 black and white photos with color filter in front of them and display the back the same way. It was one in the 1950s. It was complicated but is was used. The first full color movies was created by recording on three strips of film each with one color and physical combining multiple film strip to crate the final move that was projected. Technicolor was a system like that with films like The Wizard of Oz, Gone With the Wind. It was expensive to use and required a huge amount of light. The color filter and \"black and white sensor\" is how digital cameras work. Either by optical split to multiple sensors or a filter with all three colors distributed in a grid on one sensor."
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|
8owo4w | How does a liposuction work without ripping your guts out? | Technology | explainlikeimfive | {
"a_id": [
"e06pj1t"
],
"text": [
"The type of fat that people are trying to remove by liposuction is the visible fat that lies between the skin and the muscle. Lipo literally vacuums the fat from under the skin and never actually penetrates into the abdominal cavity."
],
"score": [
10
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8oy6qf | How did technology have this sudden boom in quick advancement from the 1950's to the present? | Technology | explainlikeimfive | {
"a_id": [
"e070nmr",
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"text": [
"I'd take issue with your starting point. There's been exponential growth in technological progress since the late 18th century. Basically, a combination of things: We devised a scientific methodology for investigating the natural world. Strong governments began to find new discoveries useful An economic and legal system developed through which resources could be directed to people with new ideas and those with ideas could profit from them. A person designing a better cart in the 15th century would have a harder time coming up with improvements without approaching the problem from a scientific perspective. Even if he found an improvement, he may make his life easier by his innovation, but he would have never thought to market his new idea to make money. Even if he did consider marketing the idea to those around him, he would have no legal protection from people just copying his idea from a strong state interested in shepherding scientific progress. Once all these factors were in place, the process of scientific innovation built on itself exponentially, as new ideas created the scope for even more new ideas and freed up more people from menial labor such as subsistence farming to innovate.",
"The Cold War. Both NATO countries and the USSR poured tons public and private money into STEM (science, technology, engineering, math) research and education. Largely for ideological and military purposes. That's why you see the explosion in cheap university education in the 1970s, and why space and science toys were so prolific in the 50s. Our modern society is all a byproduct of that."
],
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8ozafn | In videos of the damage caused by nuclear explosions, how does the camera not get destroyed. | Ive been watching videos of nuclear tests and it seems that the cameras are always fine. Additionally they seem to barely shake in some of the videos. How is this is possible when the structures they are filming get absolutely destroyed. Shouldnt the power of these nuclear weapons also at the very least shake whatever structure the camera is on? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Mostly they are far enough so that it doesn't matter. Zoom lenses are a wonderful thing. There are sometimes cases of cameras being put close enough to suffer some damage. The way they get around this is by building a bunker for the camera. [Here's a photo of a camera bunker from the Trinity test]( URL_0 ) — the whole thing is made of concrete, and the cameras face upwards, with a mirror then directing them to the test. So even if the blast wave did sheer off of the mirrors or something, the cameras would be unhurt. Nuclear effects are _very_ powerful near the fireball (ground zero). But they drop off of in intensity after that faster than most people think. So you place the camera in an area where it won't just be entirely annihilated.",
"Mostly the cameras are simply far enough away that they are not affected nearly as strongly. Second, you can affix the camera to a structure that is capable of withstanding the shockwave at the required sistance. For example, if you drill the camera into a huge boulder and place it far enough from Ground Zero, the blast eill be unlikely to affect the boulder even if it breaks down weaker structures.",
"Typically, the cameras are zooming in on the explosion, a safe distance away from the actual blast-radius. On top of this, the camera is secured somewhere in a way that even if it does experience a shock-wave or residual explosion, it only minimally damages or shakes the thing it's secured to."
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8p0901 | How does my phone know when to use the mobile version of the website? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Your phone doesn't. The web server you are connecting to detects the nature/version of the browser running on your phone (the browser returns this information when requested), and then the server sends the appropriate pages (desktop or mobile). When you select 'request desktop site', the browser sends modified information, so the server thinks it is communicating with a desktop browser.",
"Edit: the following is assuming that we are talking about websites that have entirely different mobile counterparts. I.E. URL_0 and m. URL_0 It depends on the website as there are a few different methods. But a common method is to rely on your browsers 'user-agent' information. Every browser has a specific identifier which is referred to as it's user agent. Even if you are using chrome on your phone, it would have a different user agent than it's desktop counterpart. It's important to understand the general model for how your device interacts with a server. When you type a website into your address bar and hit enter, you are initiating a connection to the server that houses the data for that URL. Your browser then asks for the files needed to render your desired web page. This is know as a request. If the server accepts the request, and if it can find the files that you need, it will then serve them to your browser. There are essentially two sets of files that make up the desktop and mobile version of the site. Through one of the several methods available, the website determines your user agent and decides which set the server should send."
],
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|
8p0m6t | If electricity moves so fast, why does it take so long for phones to charge? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Because batteries do not store electricity. They store chemicals. And when those chemicals react they MAKE electricity to power your phone. Plugging your phone in doesnt fill your phone with electrity, its using the electricity to move the chemicals back to where they were. And when that happens, the battery is able to make electricity again.",
"Actually, electricity is not that fast down a wire. Electromotive Force is fast, but the electrons themselves are slow. If you imagine a wire as a tube filled with blue balls - as soon as you put a fresh red ball in one end, a blue one will fall out the other end. However to get that red ball to fall out the end will take some time. So, when you are charging a battery you are removing electrons from one end and pushing more into the other, via the chemical reactions others have mentioned. These electrons move at a speed measured in centimetres per hour.",
"First off, charging is a chemical reaction. The speed of electricity is irrelevant. Charging can be sped up to a point, but cells have current and voltage limits. The current limit prevents the cell from overheating. The voltage limit prevents metallic lithium from forming in the wrong place, which will lead to dramatic cell failure. The devices which have been recalled for lithium batteries exploding or catching fire have almost all had overcharging problems. The charge of a nearly empty lithium cell is done with a constant current at first. This is the fastest part of the charge. When the cell reaches 4.2 volts, the charger keeps the voltage at that level. This phase is slower because as the cell becomes charged, its open circuit voltage approaches 4.2 V and the lower voltage difference means less current flows. When the current reaches a low level (around 5% of the initial current), the charging is complete. Other cell chemistries like Ni-Cd and lead acid can take full charging current for the whole charge cycle, but must be terminated before cell damage occurs. TLDR: They charge slowly to protect the cell from damage. Source: URL_0",
"Simply? Two reasons. First, moving electricity causes heat, so we need to only put a little in at a time so things don't melt. Second, think of filling a jug with a tap slightly on vs full force. Less water at a time allows the water in the jug to settle and make room for the incoming water. At full force it interferes with itself and you make a mess.",
"Think of the battery like a swimming pool. To charge it up you gotta fill the pool with water. Even if I use a garden hose with the water shooting out really fast, it is still going to take awhile for the pool to fill up."
],
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8p3ivw | When FaceTiming someone on speaker, how do they not hear themeself through the microphone from the other person? | Technology | explainlikeimfive | {
"a_id": [
"e085cb9"
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"text": [
"It's due to \"echo cancellation\". The software checks the microphone input for the same sounds going out of the speaker. If it is there, it tries to subtract it out. Good speakerphones all do this. Older (or crappier) speakerphones just cut off the mic when playing anything out of the speaker. This not only prevents echoes, but it also prevents \"feedback\". If you get a sound coming out of a speaker that goes into a mic then out the speaker and then in the mic and then out the speaker etc. etc, being amplified even a bit at every step, it quickly gets out of control and leads to a loud squeal coming out of the speakers as the amp circuits max out. Not nice."
],
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|
8p3p9y | Why do computers use 1s and 0s? | Technology | explainlikeimfive | {
"a_id": [
"e086kod"
],
"text": [
"Binary! Here's a simple video explanation that really helped me understand the concept: [**Binary \\- what is it, why is it important, and how do people interface with the language**]( URL_0 )"
],
"score": [
6
],
"text_urls": [
[
"https://airdev.co/post/demystifying-tech-episode-2-binary-1527803862469x140109900385141380"
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|
8p556c | Why aren't laptop graphics cards removable like ram or hard disk? | Technology | explainlikeimfive | {
"a_id": [
"e08ic6p",
"e08i952"
],
"text": [
"Most laptops do not have dedicated graphics cards like desktops have. The CPU and an integrated graphics chip do the graphics processing.",
"Graphics cards produce a lot of heat, so upgrading one might lead to a situation where the GPU puts out more heat than the cooling system is designed for. And to save on costs and space, most of the time graphics cards are soldered into the motherboard instead of creating multiple unique sockets, or the laptop just uses the integrated graphics card of the processor."
],
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|
8p7b13 | How did country dialing codes come to be? | I was on URL_0 and noticed that, while USA and Canada use "1", no country uses "2", and all of them seem random (a few single digits, a few two digit, most are three or four digits). Is there an explanation? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Country codes are assigned by the International Telecommunications Union (ITU), an United Nations organization. When a country becomes recognized by large, they petition for an area code, and are assigned one by this ITU. The first letter of the contry code is determined more-or-less by continent/region. US and Canada begin with +1, Mexico and South America with +5, Europe with +3 and +4, and so on. (The logic behind choosing these numbers goes to old dial telephones. It was faster to dial a lower number, and regions with more available communications got lower numbers (except Africa managed to get +2, who knows)). The following numbers are similarly chosen, a bigger, more advanced country within these regions will get a smaller number than a smaller country; like how the Netherlands has +31 but Macedonia has +389. Tl;dr, the first number is separated by region, and following number(s) are generally chosen based on how big/advanced they are; countries with more activity will typically have lower numbers for faster dialing",
"if you sort them alphabetically instead of numerically it makes a bit more sense. You could say that 2 is not used so that 200 is available. You'll notice that there are not any countries using the twenties either. This is because how dialing used to work, you send one number at a time and get redirected closer and closer to your destination, if you start sendint a 1 it knows you're going to USA or canada, because there are no countries using 10-19 or 100-199, essentially USA and canada are blocking all those. likewise there are countries using 380-389 but not 390-399 because Italy is using 39, so if you start to dial 39.. you'll end up in italy and the next digit you dial will be interpreted as the beginning of the italian number, not the next digit of a country code."
],
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8p83c9 | How does the internet get from country to country? | How does all the internet link up to one main internet? Like how can I see the same things in New Zealand, that people in America can see? At the same time? | Technology | explainlikeimfive | {
"a_id": [
"e097j3v"
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"text": [
"Short answer: Huge cables that go under water that link up between countries, often laid by private companies (Internet service providers(internet companies)) Edit: here is a link to see how the cables are laid URL_0"
],
"score": [
17
],
"text_urls": [
[
"https://youtu.be/KDcdgcRtvBQ"
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8p83z1 | Why do only some displays display HDR? Isn't a display just a series of pixels that display different color values? What makes an HDR display different? | To clarify, if my normal LCD display does not display HDR, what makes it different, hardware wise, from an HDR compatible one? I understand the HDR process when taking a picture, and the layering of differently exposed images, but then how can I view the HDR image on my non-HDR phone? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"An HDR screen is a different concept to taking HDR photos. Although both relate to using a wider range of colours. A non-HDR screen only has 256 different levels of red, green and blue. So there's only a certain range of colours and brightness it can display. HDR screens increase this so there is a wider range of colours/brightness levels. True HDR screens are supposed to be capable of more brightness, but it's not just the maximum brightness that matters, it's how many levels of brightness each colour channel has. So for example you could have a movie in HDR which for the most part looks the same as the non-HDR version, except explosions are brighter. If you just turned the brightness up on the non-HDR version, everything would just look washed out because the brightness goes up for everything. The HDR version has more brightness levels to work with.",
"The tldr is true HDR needs super high brightness or nits. Normal monitors are capable of 100-300 nits. True HDR monitors are capable of 1000-2000 nits. So looking at a HDR image of the sun is almost as looking at the sun"
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8p9nyv | How were movies edited before computers ? | Technology | explainlikeimfive | {
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"They viewed the film (on reels) frame by frame on a projector and then cut out the frames they didn't want physically from the reel. They then taped the two sections together to recreate the film. The editors were highly experienced at this, and it was done quickly and efficiently",
"I'm not sure how far back your knowledge of film/cameras goes so forgive me if I state the obvious. So let's say you take a still picture of a man with your phone. That's one picture that you can look at. Now imagine you want to take a video of the man waving. What you would do, essentially, is take many pictures. One picture when his hand is all the way to the right. Another picture when it has moved a bit to the left. Another picture where it's even more to the left. And so on. You would then view all the pictures, one after the other, very quickly. Even though they are separate pictures, because they flash past so quickly, they will fool your brain into thinking that the man in the pictures is actually waving his hand. You can see this when you edit videos - just play the video frame by frame. Each frame is basically a still picture. Nowadays, every frame of video is captured in a computer chip. However, before this happened, every frame was captured on something called \"film\". So instead of digital cameras you'd have film cameras, and every picture you took would take up one frame of film. Film came in rolls, and every roll consisted of lots of frames joined together in a strip. Cameras that captured movement worked like a still camera on burst mode. They would capture lots of pictures on a roll of film. Every frame would have a picture that was slightly different. After all the frames in the roll of film had pictures on them, the entire strip would be taken out of the camera and labelled. So let's say you wanted to have 48 frames from roll of film A joined to 24 frames from roll of film B. Well, the video editor would take roll of film A, identify the 48 frames, and then use a razor blade to slice out the part of the atrip that contained them. Then, he would slice out the part of the strip that contained 24 frames from roll of film B. Finally, he would stick them together with tape. You could then play the little movie you'd just made by running your stuck together film through a projector. I'm skipping steps in between, of course. The film had to be treated with chemicals before it could be exposed to light, for instance. But essentially, that's how it worked. It's easier to see in pictures or video, so I would advise you to search on YouTube.",
"Watch the first scene Eddy meets up with that Hollywood dude in Who Framed Roger Rabbit. You'll see a guy doing it and have a good idea",
"They physically cut the film and taped it back together. Cut sections can be discarded, or rearranged. Then the pieces are taped back together, and copied to a new single print. This entire process can be done by hand or on a number of different machines. This is also how all post-production and special effects were done for a long time.",
"Besides computers and film, there was a third way to edit movies. Videotape editing has been used since 1963 to edit. It was often been assisted by computers to keep track of the events and control the videotape recorders, but the video/audio itself did not go through a computer. BTW terms like clip and bin which are used in digital video editing programs were originally used to describe cutting the film and hanging the clips in big cloth bins."
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8paiks | How do hotel room keys work? | Technology | explainlikeimfive | {
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"text": [
"Depends what kind of keys. Tap-key cards have RFID-chips. The door reader emits very weak electric fields which powers up the chip, which spits out a unique ID. If the ID matches the reader in the door, it opens. This type is usually unprotected and easy to copy with a portable RFID-reader, which is a major security flaw. There are even some android apps which let you do this. If it’s insert-into-slot cards, it might be a magnetic strip (similar to credit cards). If the magnetic strip has the right code for the door, it opens. This type is more secure since reading magnetic strips is harder. There are also other types of cards such as mechanical key cards with multiple holes, but these are more rare."
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8pb7j7 | I saw an advertisement for a keyboard saying the keys can withstand 50 million clicks, how do companies test this? | Technology | explainlikeimfive | {
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"with a clicking machine. they test smart phones the same way. little rubber do-dad on a robot arm tapping a million times",
"Actually, this may be easier to test than another commonly asked question— about lightbulbs which advertise 5,000 hours of life. If you click them fast enough, you may actually be able to test many millions of clicks in a manageable amount of time. They still likely use *extrapolation*. After a smaller number of clicks, a few will start to fail. This will happen more frequently as you approach the number of clicks that a *typical* switch fails at (half fail before that time, half fail after). If you analyze the speed of failures you can predict the shape of the failure pattern, and where it will peak. This assumes they fail more or less randomly with increased use, not catastrophically after a certain number of clicks due to some specific part that wears out. But that’s usually a fine assumption for those sorts of things.",
"They don’t physically test to that extent. It’s a lot of statistics and probability that gets them a certain number, and then the business side adds a safety factor to make it difficult to sue."
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8pbyoe | how small can pc chips really get, the recent introduction of 7nm chips from AMD made me think is there some kind of limit? | Technology | explainlikeimfive | {
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"Yes there is a limit. if 7nm isn't the limit, you can see it from there. Given AMD's yield numbers, it might be 10nm. Quantum mechanics says that an electron isn't a little billiard ball of charge, it's a cloudy region where the charge is statistically located. When features get too small, the individual electrons can \"tunnel\" through the insulator walls and get out of one part of the circuit and into another part unpredictably. It's like using a pipe with holes in it, you can make the place at the end of the pipe wet, but you can't easily make it enough wetter than the places under the pip that it encodes a \"1\" or \"0\" of information. When everyplace is wet, you can't compute with \"wet\" vs \"dry\".",
"Yes there is a limit, however it's important to note that AMD's \"7nm\" process isn't 7nm in the strictest sense. A number of years back (around 45nm) chip manufacturers began moving their naming away from being an engineering measurement and more toward being a marketing name. Remember that they're not just doing a straight up shrink of the previous transistor designs where only a single number would be needed to describe them. Often improvements come in the form of more subtle alterations that don't actually involve making smaller transistors, just tighter clearances and the like (in fact some of these actually increase the size of other elements as a trade off). To my knowledge nobody uses pure size to define their process anymore though Intel has been somewhat conservative in how quickly they push their marketing terms ahead. This is apparent in how the various pitch measurements of Intel's \"10nm\" process are actually in line with the measurements that most other manufacturers like AMD are already calling \"7nm\"."
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8pcrs5 | Why is it so important to rinse food from recyclables, but it isn’t necessary to rinse soap or lotion from containers? | Technology | explainlikeimfive | {
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"Getting rid of food from recyclables is only important for hygiene reasons (rats, flies), they can be recycled no matter how dirty they are."
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8pdhvp | Why do computers need to update? | Technology | explainlikeimfive | {
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"For security purposes mainly. There's always new exploites people can use to put malware into your system. Updates help to try and prevent it.",
"There is a wide category of cases why you might need an update. **Bug fixes** * consumer software is never bug free. Supposedly the only way to create 100 & #37; bug free software is to make sure that software is mathematically provable. Almost all mainstream programming languages do not allow for this to be easily done. * Just because you haven't seen a particular bug doesn't mean it is not there. You might not have encountered it yet but as you use more features of a given piece of software the more likely you are to hit it. **New Features** * While one person might be happy with what they have many others might not be. There are always customers who are asking for feature X or feature Y. * Customer acquisition is what drives a lot of this. If you were already the best out there and had tons of customers you probably won't bother as much with new features (as the risk/reward curve isn't in your favor). If you do this competitors will usually come up and try to fill in those features (and eventually replace you). * integration with other new software. A lot of software now\\-a\\-days tends to rely or be relied on by other software. A lot of software will have interfaces for others to use. Sometimes these interfaces are discontinued and therefore everyone else who relies on it needs to be updated. * MacOS just discontinued support for OpenGL in favor of their newer Metal Interface. This means pretty much every game designed to work on MacOS for the last 10\\-15years will be screwed unless they update them to work with the latest Metal interface (unlikely for really old games). **Security** * Lots of developers don't know much about software security. They will have a certain security threat model in their head (essentially attackers they want to protect you from) but it is usually inaccurate. * A perfect example of this is facebook with Cambridge analytics. Facebook claimed it was focusing on trying to protect unauthorized users from being able to break into accounts, servers, etc.. (their threat model) The real threat was one of their customers was using their data for something that could be classified as illegal. * Software it depend on could have security holes. Its your softwares job to make sure it protects itself and you regardless if the underlying stuff/software is insecure. One thing all these broad categories have is that they are trying to benefit the end user. Its true that sometimes an update comes out that makes a few users lives worse off. This is almost never the goal."
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8pf32d | how come when you speed up a song on YouTube, it doesn't get that "Alvin and the Chipmunks" effect you get when you speed up a vinyl record? | Technology | explainlikeimfive | {
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"Essentially it’s because computers are smart. Sound is a wave, with how high or low a sound is being determined by how many waves it has per second. More waves = high pitch. So when a recording gets played at a faster speed, be that a record or on a computer, more waves come out in the same amount of time, so everything gets higher pitched. Computers can also do this thing called “tone shift” though, where they go through a recording and shift it to be higher or lower pitched by detecting and then adjusting how long the waves are for a given sound. Computers can use these two in combination to get a video that is faster/slower and still at the same pitch, or higher/lower and still the same speed (there are also a few algorithms that can do speed changes directly and don’t involve doing both so you can process faster). The YouTube player is smart enough to do this, but a record player (obviously) is not.",
"It's using a pitch changer to essentially change the high pitched sound from playing it faster, back down to where it normally should be. It's not perfect however, and you can often hear artifacts in the sound which make it sound a bit odd."
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8pgao0 | With the resolutions and graphics capabilities we have, why aren't we capable of of creating a simulation of a person that's visually indistinguishable from a REAL person? | Technology | explainlikeimfive | {
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"Render times are too long for realistic hardware. Your eye is going to spot the flicker of 15-20 frames per second, so you need to be 30+ or better to even have a chance at fooling the brain. So now you're talking hardware that can render a photorealistic image 30 times a second. That would cost you a not-so-small fortune. The computers that do this kind of visual rendering for movie CGI can take hours to do a single frame. The end result is quite convincing these days, but they can't do it in real time."
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8pgj92 | Why are the decimals in AM/FM radio stations always odd-numbered? | Technology | explainlikeimfive | {
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"Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do FM radio stations end in odd numbers? ]( URL_3 ) ^(_9 comments_) 1. [ELI5: Why is FM radio on only odd frequencies and only frequencies between about 90 to 110? ]( URL_6 ) ^(_40 comments_) 1. [ELI5: Why do all radio stations end with an odd number after the decimal? ]( URL_2 ) ^(_21 comments_) 1. [Why do radio station frequencies always end with an odd number? ]( URL_5 ) ^(_2 comments_) 1. [ELI5: Why do all radio stations end in an odd decimal? ]( URL_1 ) ^(_ > 100 comments_) 1. [ELI5: why are all the FM stations ending with odd number always? ]( URL_4 ) ^(_3 comments_) 1. [ELI5: Why can you only tune FM radios to odd numbers? ]( URL_0 ) ^(_13 comments_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/65yq5t/eli5_why_do_all_radio_stations_end_with_an_odd/",
"https://www.reddit.com/r/explainlikeimfive/comments/27j3e7/eli5_why_do_fm_radio_stations_end_in_odd_numbers/",
"https://www.reddit.com/r/explainlikeimfive/comments/4au3lf/eli5_why_are_all_the_fm_stations_ending_with_odd/",
"https://www.reddit.com/r/explainlikeimfive/comments/1kwnt5/why_do_radio_station_frequencies_always_end_with/",
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8phmk8 | how can a tv remote sit around all day not wasting it’s batteries and immediately be picked up and used (without having to be turned on), while something like a game controller must be turned on first before use, and if you left it on all day it would drain the batteries even while not in use? | Technology | explainlikeimfive | {
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"a tv remote is a usually one way communication and uses IR. the remote emits a signal when a button is pushed and the tv receives it. it's like using smoke signals. a game controller communicates through bluetooth which is active two way communication. just by keeping it on and idle, it'll consume power. and controllers can also do other things, such as transmit audio, rumble, etc.",
"A TV remote is typically made in such a way that every button is an \"on\" button for the remote itself. Meaning it uses absolutely no power when you're not pressing any buttons. So the reason is the same as for a flashlight -- when not in use it doesn't do anything.",
"Many answers here mention that remotes use IR, which is one-way, while controllers use bluetooth, which is two-way. This is close to being the answer, but I just wanted to add a bit extra. The important thing to note is that bluetooth is connection-oriented. Devices establish explicit connections with each other, and then either device can talk to the other over the established connection. Now, because devices want to connect as soon as they can, they have to constantly be trying to connect, meaning at regular intervals they're sending out a signal just asking \"anyone else nearby speak bluetooth?\" This uses power. Of course, devices can get around this by either giving up and going to sleep after a while, which means the user will have to \"wake up\" the device before it tries connecting again. Another reason controllers might draw more power is that electronics just always draw a little bit of power, even when they're completely off, and more complicated electronic with more components are going to draw more idle power. And since a controller is much more complex than a remote, it draws more idle power. On top of that, since the best way to prevent this idle power loss is to physically disconnect the battery, IR remotes can just use every single button as a physical disconnection, so the battery is only even connected to anything when a button is pressed. In a controller, a bunch of components need to be on continuously, even when no buttons are being pressed (like the bluetooth radio). So, to counteract the idle power draw, controllers come with on/off switches, which can be used to physically disconnect the battery from the electronics and saving power.",
"A basic tv remote just blasts an ir signals into the ether depending on which circuit is completed, it’s the TVs job to receive the signal. Your game controller has to send AND receive a constant stream of very complex signals, when you aren’t using it and it’s left on it still has to sit there and constantly check if anything has changed which drains its battery.",
"Remotes are pretty dumb and do very simple things, like shooting out the same signal every time you push the same button over IR. Controllers actually have some smart bits in them, talk both ways, and are generally much more complex.",
"I'll address it in two parts: 1) TV remotes do drain batteries but do so at a very slow pace. The basic structure to TV remotes use an LED at the infrared frequency range that characteristically blocks most current from the battery until someone turns it \"on\". When you press a button it turns on for a short burst, then back off. You also have to program a remote when you start because the receiver at the TV only responds to a certain type of signal. 2) The actual use of a game controller vs a TV controller are pretty different. A TV remote signal is very directional; if you don't point it at the correct spot you don't get the channel changed or the volume changed, etc., this wouldn't be convenient for a game controller. You also care about missed inputs, having a two way connection instead of a one way connection like a TV remote means you need constant talk between the game controller and system. This means quite literally in-between all of your inputs on your game controller the system and controller are both communicating with \"hey I'm here \" and \" do you still see me signals\" on top of other things. Newer features have reinforced the need for this type of partnership (things like rumble) real ELI5: They were built to do different things, a lot of what a game controller does requires input from you and the game system. Doing this requires energy for working in both directions. Talking both ways requires synchronization as well (in order to understand each other) so that's why they use power even when not being used to make sure they are still synced (most have power saving built in to disconnect after so much time of no use) They could have made game controllers work the same way as remotes but you wouldn't have the benefits of the feautures like rumble etc. Sorry for the long stuff, went on one of those onion peeling journies Source: PhD student in EE, specific in wireless",
"Most of the popular answers here are wrong, those reasons are why the controller's battery doesn't last long while in active use, not the reason it has terrible standby power usage. The real reason is because the people that made the game controller didn't prioritize low standby power usage. It's entirely possible for the engineers to make the game controller go into a low power mode if it's idle for say 5 minutes, but for whatever reason(cost or development time) they didn't bother. Even with a bluetooth receiver active(but not transmitting), two AA batteries can last a month or two in an idle/standby mode. Provided the developers care about standby time.",
"TV remote buttons complete a circuit for the battery, and thus electric current is used. This is a tiny amount of power. If the remote isn't used, it's like the batteries aren't even in the remote. The IR light is a single light that sends bursts of light patterns. A controller using Bluetooth or other method of communication is always using a wireless connection to stay in contact to communicate actions done on the controller. Think of it this way: a remote is you and a friend sitting around where you can occasionally tell your friend something. A controller is where you two need to constantly ask your friend every 10 seconds if he is still listening. Which scenario will cause you to be more tired at the end of the day?",
"Think of a complete circle. Now think of one that is incomplete, or 95% drawn. You know it’s a circle, but it’s not connected. This is how circuitry works. If the circle is complete, batteries drain. If the circle is not complete, nothing happens. Most TV remotes are simple and use an open circuit (incomplete circle). You are closing the circle when you press a button. The circle is only complete and only draining batteries during that button press. When you let up the circle opens and once more, the batteries go back to their non-functional, incomplete circle state. A game controller is more complicated. It works with an always-closed circle. The button that turns it off and on is not the same as a tv remote. The game controller always has a low level of power running through the system even when it’s off, hence the batteries drain. Circles.",
"A remote only sends a signal when you press a button. A console is constantly pinging a controller, checking its current input state every fraction of a second. Also; remotes don't vibrate.",
"- A TV remote is basically a torch (press a button to shine the infra red light). - Your game controller is basically a two-way-radio (it's constantly sending and receiving UHF radio waves while it's turned on)",
"Many game controllers are two way devices. So assuming you could make one that worked exactly like a remote, it would still have to \"listen\" to see if the console is telling it to \"do\" something, example \"rumble\". For that reason there is always some battery usage. If you wanted to minimize it you could remove the rumble pack although with most today it is integrated.",
"Every button in a remote is essentially a tiny switch. If you open up a remote, you'll see on the circuit board inside there are little black pads that line up with each button on the remote. When you push a button, you essentially complete the circuit for that individual button, which then sends the appropriate signal to the device (volume up, channel change, etc.). Then when you release the button, the circuit is broken, meaning no current flow, and no loss of battery life until another button is pressed. This wouldn't work with a gaming controller because as stated above, it is only one way communication, and a lot of the functions of a gaming wouldn't work with one way communication."
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8pk2wa | What is a DDoS attack? How do websites like cloudfare mitigate them? | Technology | explainlikeimfive | {
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"Most companies that provide a website have web servers for the purpose, or dedicated computers that are optimized to be able to handle 500,000 to millions of data requests per minute. A [denial of service attack]( URL_2 ) is an attack that tries to overload these servers or computers, by requesting data millions of times and not giving time for the server to respond. The idea is to make the server so busy that it can't respond to regular customers, so regular customers see an outage. Because server computers have gotten pretty good at handling millions of requests like that, in order to get through and overload a modern server, you need 20,000 or more computers to perform this attack, so that you can generate the millions of requests and the huge traffic. So, for a distributed DoS attack, you have hackers that infect some 20,000 or more random computers with a virus, and this virus doesn't delete files or anything like that, it just stays hidden / silent, until the hackers give the order, and then your computer along with 19,999 others all start to spam the target server with requests, all at the same time. The way to mitigate a DDoS attack is to realize it's happening, and then block the requests from reaching the servers, or disrupt the 20,000 attacking computers from being able to request data so fast. [Cloudflare]( URL_0 ), specifically, asks the 20,000 computers to \"I'll give you your information, but first answer this [captcha]( URL_1 ) question to prove you're a human and not some virus script.",
"Distributed denial of service attacks. Imagine you know of this really great donut shop in your home town, lots of people go to it every morning, it's full but they manage to get people in and out and make enough donuts for everyone to be happy. Now imagine you say \"THEY MESSED UP MY JELLY DONUT!\", you're pissed, you're furious, that was the one thing you got for yourself everyday and they messed it up. So you go and get 100 of your friends to all rush into the store at the same time during the peak of morning rush. There are so many people jammed in the door way that no one can get in our out. You just DDOS a donut shop. DDOS is just sending a ton of traffic at a website so that it get's congested. Generally this is done by several hundred computers (distributed part of DDoS). Website can detect these usually just by monitoring traffic and seeing if there's a odd spike. If they notice it, instead of letting you flood their donut shop, they end up just closing shop for a few minutes until you and your friends leave. No more bodies in door ways, just locked doors (which are much easier to clear out to allow traffic). Now instead of an hour of down time, it was just a few minutes."
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8pkl25 | If TV remotes emit infra-red rays, then why does camera lens pick violet rays being emitted from the remote? | Normally I can't see any light being emitted from remotes, but when I use a mobile camera for viewing I see a bright violet-ish light coming from the remote | Technology | explainlikeimfive | {
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"First, a quick introduction to how camera sensors work: Camera sensors actually just see in \"black and white\". That is, they only measure light intensity, not frequency. The sensor itself doesn't know if a photon hitting it has the \"red\" wavelength or the \"blue\" wavelength. To figure out which wavelength a photon is of, a filter grid is placed on top of the sensor to allow the camera software to figure out what colors things are. If the filter over sensor pixel number one only lets blue light through, the camera knows that if pixel #1 detects any light at all, it is of the blue variety. The filter on top of next pixel on the sensor only lets green light through, so if the same blue light hit that part of the sensor, it would be blocked by the filter and the sensor wouldn't show any light at that spot. This process is repeated for all of the several million pixels the camera sensor has, and when the camera software combines the information about how the color filter is arranged with the light detected by the sensor, it can use this to calculate a color image even if the sensor is only able to see black and white. So, let's say an infrared photon hits the camera sensor. If the color filter i mentioned earlier isn't made to block infrared wavelengths, all pixels on the sensor get lit up by it. Slight variations in each color filter's ability to block IR wavelenghts might cause the blue filter to block less of the IR than the other two colors, but still not all of it. As a result, it would show up as bright with a purple tint. If the red filter had been able to block 100% of IR radiation, but the other two filter did not block it at all, the IR would look cyan. You can read up on bayer filters for more information. URL_0 tl;dr: All camera sensors are sensitive to a wide range of light and don't natively see in color. The weird color from non-visible light is caused by the color filter on top of them not blocking IR and UV perfectly, or at all."
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8pllj3 | How Speakers Produce Audio | How does an object consisting of metal, magnet, wire, and paper/plastic produce audio? I’ve torn them apart before and they look super basic and I don’t understand how they produce audio. | Technology | explainlikeimfive | {
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"Their operation is not really that complicated. First of all, sound is essential just a pressure wave in the air. Very similar to a wave in water. In water you can easily create such a wave by placing your hand in it and moving it back and forth. This is exactly what a speaker does. It's just a piston that makes the membrane move back and forth, causing pressure waves in the air. The mechanical movement is caused by a permanent magnet which gets pulled or pushed by an electromagnet. You can usually see those vibrations at low frequencies."
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8pmlkd | Why or how do the magnets in those magnetic car phone-holders not affect the electronics in phones? | Technology | explainlikeimfive | {
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"Phones don't use magnetic storage (tape, hard drives), it's all memory chips nowadays. So a static (not changing) magnetic field doesn't affect the electronics inside. A changing magnetic field, on the other hand, like the field produced by transformers (vibrates at 60 hertz) or lightning or static electricity (sudden pulses - EMP) can cause runaway electrical currents in the electronics, due to the [electromagnetic induction]( URL_0 ) effect. Also, iron/steel and other [magnetic materials]( URL_2 ) are very good at [directing the magnetic field]( URL_1 ) through them, and thus away from the surrounding (air)."
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8popav | How does this topographical sand work? | URL_0 Really confused on how those topographical sand works. | Technology | explainlikeimfive | {
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"A Microsoft Kinect is used from above to measure the height of the sand, and a projector displays light onto the sand according to its measured height. Edit: found a picture URL_0"
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8ppd9s | And why are video games for certain consoles still sold as discs when the game is installed to the hard drive anyway? | Wouldn’t it be more cost-effective for the companies making the video games (and possibly the consumers buying the games too) to not sell them as discs and only Offer them as digital downloads? Speaking for myself I know as a consumer that using the discs on these newer consoles is an inconvenience… Nothing is more annoying then having to get up and put in a different game just to be able to play it. However, with older console such is the NES SNES and N64, there’s no greater feeling than putting in the new game which is odd | Technology | explainlikeimfive | {
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"Downloading games is more cost effective for the producer, but not necessarily the consumer. In certain countries and places bandwidth is expensive. I remember reading about an Australian gamer that was fuming that he pre-ordered a physical copy of a game only to get an empty CD case because it was download only. The game was over his monthly bandwidth cap from his ISP so he had to pay extra to download the game.",
"Not everyone has fast enough internet to download a bunch of gigabytes to play something. In many places, people still have data caps. A physical disc can be sold in a store. A lot of people still insist on getting *something* tangible when they make a purchase. A physical disc acts as a \"dongle\" to show you actually paid for the game that doesn't rely on an internet connection."
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"url"
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8ps3j4 | What is a tensor? | I read the [Simple English wikipedia entry]( URL_0 ) but I'm going need you to dumb it down a shade for me. Please ELI5, what's a tensor? | Technology | explainlikeimfive | {
"a_id": [
"e0dxmdw"
],
"text": [
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What is a tensor? ]( URL_5 ) ^(_17 comments_) 1. [ELI5:Tensors ]( URL_0 ) ^(_16 comments_) 1. [ELI5: What is a tensor? ]( URL_4 ) ^(_9 comments_) 1. [ELI5:What are tensors and what are they used for? ]( URL_2 ) ^(_1 comment_) 1. [ELI5 (or ELI29): Tensors ]( URL_3 ) ^(_2 comments_) 1. [ELI5: What exactly is a tensor? what are the differences between metric tensors, stress-energy tensors and any others I am excluding? ]( URL_1 ) ^(_1 comment_)"
],
"score": [
3
],
"text_urls": [
[
"https://www.reddit.com/r/explainlikeimfive/comments/2dwnk9/eli5tensors/",
"https://www.reddit.com/r/explainlikeimfive/comments/1wixgz/eli5_what_exactly_is_a_tensor_what_are_the/",
"https://www.reddit.com/r/explainlikeimfive/comments/6aq8t1/eli5what_are_tensors_and_what_are_they_used_for/",
"https://www.reddit.com/r/explainlikeimfive/comments/rgonq/eli5_or_eli29_tensors/",
"https://www.reddit.com/r/explainlikeimfive/comments/5lgc5t/eli5_what_is_a_tensor/",
"https://www.reddit.com/r/explainlikeimfive/comments/5f78h2/eli5_what_is_a_tensor/"
]
]
} | [
"url"
] | [
"url"
] |
8psd14 | Why do objects in cartoons that move/will move appear brighter/more vibrant than objects that are stagnant in that scene? | Technology | explainlikeimfive | {
"a_id": [
"e0dncni"
],
"text": [
"If you're talking about old cartoons, then that's because those objects were drawn separately. The background of a scene in a cartoon is generally a single drawing. The moving objects or characters are drawn on a separate transparent sheet, called a \"cel\", which is then laid on top of the background and photographed. A new cel is made for every frame."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
8psp90 | - Why are Li-ion batteries so prevalent in every size except AA, AAA, etc? | Technology | explainlikeimfive | {
"a_id": [
"e0dpwqp",
"e0drrms"
],
"text": [
"Electronics that use AA batteries expect around 1.5-1.2 volt. Li-ion batteries deliver around 3.7 volt. Applying 3.7 volt to something that expects at most 1.5 is likely to cause damage or at least not work properly. You'd need to put a circuit inside the AA battery the converts the 3.7 volt to 1.5 volt.",
"In addition to the voltage differences mentioned earlier, you’re also going to have to deal with a different naming convention. Try looking for 14500 cells (AA size) and 10440 cells (AAA size). There are some devices that require these sizes of cells for proper performance. The numbers refer to the physical size of the battery— 14 (diameter) x 50 (length of major axis) for the AA equivalent, and 10 x 440 for the AAA equivalent. Be VERY sure that the device can handle the power of the Li-ion cell before you insert the cell."
],
"score": [
13,
9
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
8pufh6 | How does an earphone, that is plugged into an audio jack or a USB port, get the power to run? | Devoid of any battery or external power source, do these earphones get power from the jack or port itself? If so, how can the power and audio be transferred from the same cable and separated by the earphone? | Technology | explainlikeimfive | {
"a_id": [
"e0e3goz",
"e0e3ha0"
],
"text": [
"They receive the power from the plug. If I remember correctly, it’s the pulses of electricity that drive the tiny electromagnet inside the speaker that makes the noise as it vibrates the diaphragm. WhT you’re hearing is the vibration of that piece of paper/plastic as the magnet reverberates it.",
"A USB port has power as well as signal. Not a lot of power, but enough to power a memory stick, for example. I've seen solid state drives which no longer need wall socket power, just the power which comes across the USB port. Also, some newer DVD drives. I'll leave the audio jack part for someone else to answer."
],
"score": [
7,
4
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
8pun9b | Rechargeable batteries. Do they stop charging once fully charged? Does it damage the device if left plugged in? | Technology | explainlikeimfive | {
"a_id": [
"e0e78ik",
"e0e5vrp",
"e0eeht5"
],
"text": [
"Chemical batteries react to produce useable power when connected to a circuit, and this reaction is reversible in a rechargeable battery. When the battery charger charges the batteries up again, the battery chemicals will reach a point where the reaction has been fully reversed. From this point, the energy that was going into the chemical reaction can get wasted as heat in the battery. If the charger isn't designed to detect this, it will keep pumping power into the battery and could damage it via this heat. Most modern chargers will detect the full charge and stop pumping in power to the battery.",
"I can say about Apple devices. They stop charging the battery when it is fully charged and restart when it drops below a certain level. So overnight charge is fine. Source: URL_0",
"There are multiple kinds of rechargeable batteries. In modern electronics such as laptops and smartphones and even electric cars, you almost always have lithium batteries. These have special charging circuits built in that make sure you can't overcharge (or under-discharge) them, otherwise they could overheat and explode. This is true even if you leave them plugged in. Other batteries, like NiMH (nickel metal hydrid, such as Eneloops) or NiCd (nickel cadmium, often used in battery powered drills) can be left to charge indefinitely at a low current without causing significant problems (they won't explode or anything, but it can shorten the battery's life). This is called \"trickle charge\" and most cheap chargers will use this method. These chargers don't have special protection circuits so they're cheap, but they take half a day to charge the batteries. To charge them faster, you can get fast chargers that supply more current, and they also have protection circuits to shut down charging once the batteries are charged, as the higher current could damage the batteries after a while. Modern devices make sure that you can't damage batteries if you leave it plugged in for too long, so you don't have to worry about that."
],
"score": [
5,
4,
3
],
"text_urls": [
[],
[
"https://www.apple.com/batteries/why-lithium-ion/"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
8pwn00 | Why do smaller downloads seem to go at slower speeds/Larger downloads at higher speeds? | Technology | explainlikeimfive | {
"a_id": [
"e0ely84"
],
"text": [
"It takes time to establish a Connection to the server you're downloading from, which may seem longer with smaller downloads since the time it takes to establish that connection might be as long as the actual download time. Also smaller downloads usually contains a lot of smaller files instead of a few big files (bigger files are easier to download than a lot of smaller files)."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
8pxm76 | How does the hawk-eye technology work ? | Technology | explainlikeimfive | {
"a_id": [
"e0f7ehq"
],
"text": [
"Hawk-eye is just one of several systems that organizations are using to do things like assist refereeing. It's likely several (more than 2 I imagine) cameras synchronized on a computer that runs a relatively simple computer vision algorithm to identify the ball from live feeds. If the cameras are synchronized properly you can take the position of the ball relative to each camera at discrete time markers and work out a 3-dimensional location of the ball at any given time. Once you have this information, it's also possible to e.g. use the last few milliseconds to anticipate trajectory."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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