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Sensei

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Everything posted by Sensei

  1. Where have you seen such a phenomenon? Show us the circuit, maybe you misunderstood something. General simplification for the layman: 1) A resistor limits the current through the wire. It can be used as voltage divider. 2) A capacitor stores electrons on plates for later use. 3) A coil stores energy in magnetic field for later use. 4) A diode blocks current in one direction. If the current exceeds the limits ("specifications") of the components, the component is unable to dissipate the energy fast enough and sooner or later fails. It is a function of current, voltage (and therefore power, P=I x U) and time (and therefore energy, E= I x U x t = P x t ). There are graphs that show how long a component can withstand an overcurrent or overvoltage. Any element can fail, if its specs are overly and lengthy exceeded. Failure symptoms: 1) A defective resistor will usually be 0 ohms, i.e. it will no longer pass current. That is, it limits the current to zero through its wire. 2) A defective capacitor does not store any electrons anymore. 3) A defective coil usually passes no current. i.e. it does not store any energy anymore. 4) A defective diode usually does not pass current, i.e. it limits in both directions, instead of only in one. The energy entering the wire is equal to the energy leaving the wire minus what was consumed by the elements and dissipated as heat. The number of electrons must be equal (unless you have some kind of device that ejects them into space). One of your the previous threads was about smps. It is the coil that stores energy and causes the voltage to rise, not the diode. Since the coil has stored energy, and part of the circuit is intentionally turned off, it must release stored energy. And it does so in a very short time. The number of electrons is constant, so the only thing that can be increased is the voltage (Q=I x t, E=Q x U = I x U x t). There is a voltage spike, which is later smoothed by capacitors. Although in typical domestic applications, smps usually generate lower voltage than the input AC voltage. Lower voltage, such as 5 V, 12 V, 24 V, but with higher current than the input voltage of 230 V or 110 V.
  2. Programmers, especially in the past, use lookup tables (LUTs), to speed up an extensive mathematical algorithm. In the '80 years, in CPUs without multiplication implemented in hardware, LUTs were even used for multiplication and division. Multiplying 8 bits by 8 bits requires 65536 16-bit LUTs = 128 KB (which can be in ROM!) https://en.wikipedia.org/wiki/Lookup_table "An n-bit LUT can encode any n-input Boolean function by storing the truth table of the function in the LUT. This is an efficient way of encoding Boolean logic functions, and LUTs with 4-6 bits of input are in fact the key component of modern field-programmable gate arrays (FPGAs) which provide reconfigurable hardware logic capabilities." Example in C/C++: uint16_t multiply_lut[ 65536 ]; // Initiated by the user once at startup. uint16_t multiply( uint8_t src1, uint8_t src2 ) { uint16_t result = multiply_lut[ (uint16_t) ( src1 << 8 ) | src2 ]; return( result ); }
  3. The diode passes current in one direction and does not pass it in the other direction. This is the case only in theory. There is a voltage that causes the diode to let current through in the opposite direction. But a Zener diode is designed to let current through sharply at a well-defined threshold voltage. As a result, too high a voltage does not reach (in theory) the parts protected by the Zener diode. Zener diodes are often used in pairs: When you have element at hand, or on circuit, you should check its specification and charts like: ..and read Wikipedia about it for general information.. ps. Not without a reason people invented RTFM. https://www.google.com/search?q=RTFM
  4. ..finally we have explanation of many things.. thank you so much for sharing this with us..
  5. Actually your post makes no logical sense to me. I can see the errors in the source code, so I can predict that sooner or later it will crash and under what circumstances (cumbersome for others to foresee, especially the "children of the debugger"). Telling another programmer that he/she made a mistake in line X is unethical? If I tell "fix this or people will die because airplane or spacecraft will crash", somebody will tell "right" and simply ignore my advice, I foresaw this disaster and this happened. If programmers/engineers will fix it, then can tell "you foresaw nothing, as nothing happened, see? There was nothing to worry about!".. People say so about the Y2K problem (although a spaceship was destroyed by a similar mistake!), and so now they say about COVID-19.. ("they scared us for nothing!")
  6. Number six: get out of the house so the whole premise can't happen. Number seven: you shoot yourself before two hours, so the whole premise can't happen. There's a (forty year old) movie about it, but instead of a "being of superior knowledge" it's just a gypsy fairy.... https://www.imdb.com/title/tt0074251/ "Modest editor, has shipped his wife and kids for the weekend, and is trying to relax in his house at the outskirts of Warsaw. His quiet evening is only disturbed by the accidental forecast made by a Gypsy woman, that at evening time he will murder a mysterious brunet. He is trying to escape the destiny, but to no avail" (it is a satirical comedy, you would love it)
  7. People are slaves. Slaves of money, most of them, except some homeless and some billionaires etc. And slaves to tradition, rituals, the religion they were raised in, addictions, etc. How can you say you have free will if you can't even wake up when you want? The clock rings at 5, 6 or 7.. and you rush to work, which you hate..
  8. STM (from the article that you just linked) is not one of them.. ..then you would not build an electron microscope, but a tunneling microscope.. It's a completely different technology, with different operating principles.. ..what is your definition of an electron microscope.. ? "An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing them to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher resolution of about 0.1 nm, which compares to about 200 nm for light microscopes." STM is not listed on the list of electron microscopes, and they clearly stated: don't confuse with STM: https://en.wikipedia.org/wiki/Electron_microscope ps. Personally, I would prefer to build an SEM. ps2. A good starting point would be to create a 3D printer or 2D printer/plotter with high motion resolution (so that the electron gun remains stable and the sample moves slightly below).
  9. https://en.wikipedia.org/wiki/Scanning_tunneling_microscope "Not to be confused with scanning electron microscope (SEM)." https://en.wikipedia.org/wiki/Scanning_electron_microscope "Not to be confused with Scanning tunneling microscope." STM != SEM..
  10. Some people have been on the forum (any forum) too long and too bored with the forum and answering (newbie) people, they become unbearable and a cumbersome to the rest.. unable to answer any simple question.. We have seen this in the past.. Some of them were banned because they were too disruptive.. I'd call it professional forumer burnout.. It's very simple. When you accelerate an electron with a well-known voltage, it hits something. Their kinetic energy ranges from zero to that voltage, expressed in eV (e.g., 5,000 V will get you from 0 to 5,000 eV K.E.) If it has high enough energy, it causes the electron to be ejected. When an electron is attracted to an atom or molecule, it must emit a photon. We have 1) electrons that have been ejected and 2) photons that were emitted by electrons attracted to an atom or molecule. Ejected electrons and/or photons can be captured by sensors. Reflected electrons can be captured by sensors. Their energy (kinetic energy) (thus velocity), angle and time of flight from the primary emitter to the object and then to the sensor can be measured. A computer algorithm reproduces this in the computer's memory and displays it on the screen. Don't be silly. Electron microscopes are damn expensive and this is not a project you can do at home. At least not you.. Making an electron gun requires a fairly good vacuum. https://en.wikipedia.org/wiki/Electron_gun The number of calculations here is in the billions, so your little knowledge of Python is not enough to create a program. You need C/C++.
  11. Hello! They were sending them to jail! And then - do what you want - at least here.. If I send you to a space station on the moon or Mars and then release you, you will be in the same situation as they were 200 years ago....
  12. In the Concentric Universe. but parallel means that there is independent variable with the same x,y,z,t.. How does it fit into your "Concentric Universe" theory.. ?
  13. Unfortunately, you did not pay enough attention to the discussion.. As big as something is, the discussion of volume.. When I was asking about the mass.. ps. Phi apparently not for everyone.. In which parallel Universe?
  14. How does the TARDIS bag summarize the weight contained in the bag? (volume vs mass problem) If this is really a reasonable question, you should start by creating an algorithm, e.g. by searching out Internet what the weight (and the volume) of the animal is, what percentage is bone, fur, head and other dispensable parts. The real meat is then dried (i.e. even further reduction of mass, i.e. water in it). https://www.google.com/search?q=drying+salt+meat https://www.google.com/search?q=dried+meat "To dry cure meat with salt, cover it entirely in salt for a full day. In order to make sure the meat is completely covered, fill a container with salt, place the meat on top, and pour more salt over until it's buried." https://www.google.com/search?q=cured+meat+weight+loss "The meat should lose 35-40% of its weight by the end of the process, and the only way to tell when the meat is finished curing is to weigh it." The weight of human bones is 14%. (Measure the weight of the jumbuck by yourself, before and after) So, if we assume a similar bone mass, out of a 50 kg animal - 50x14% = 43 kg x 60% (due to drying) = 26 kg. The head and fur go off first, as do the internal organs (they would go bad first). At least 50% of mass, and even more volume, is gone. https://www.google.com/search?q=lowland+sheep+lamb "The animals' body weights were monitored from birth to day 180, when they were slaughtered. At slaughter, the lambs reached an average body weight of 38.82 kg. The percentage of slaughtered parts, slaughter yield and the proportion of cutouts in the half-carcass were tabulated."
  15. ..unlikely.. HTTP/HTTPS web archivers work only with true HTTP/HTTPS servers.. but Facebook and Twitter are dynamically generated JavaScript servers. They change stuff depending who is watching it, and (try to) ignore bots.. i.e. archiver will get nothing.. Some (devs) says "use WebAPI".. Have you seen the "prove you're human" requests (created by Google!) where you have to click something in the right order...? Web archiver won't work with that - and it won't archive pages.. Entire FB, Twitter are "blank pages" for automatic archivers.. ps. I have created HTTP/HTTPS search crawlers. (like "Google").. Google demands data from you, to index pages, and at the same time, dismiss giving you their data.. The result will be equivalent to "dark ages" like three thousands years ago in the Greece.. https://en.wikipedia.org/wiki/Greek_Dark_Ages They even want to speed up the collapse by automatically deleting data due to user inactivity. Two or more years without logging into an account and deleting the account. The days when "Google is cool" passed about twenty years ago..
  16. Why do you write such nonsense? Matrix operations are nothing more than operations on multiple variables simultaneously/parallely. If you have matrix 2x2, you have 4 equations. If you have matrix 3x3, you have 9 equations. If you have matrix 4x4, you have 16 equations. etc. The operation between vector with n-th element and matrix which has n-th x n-th element, can be expressed (for somebody reading it) as an array ("matrix") of equations. For example (the simplest case), the scale matrix will have a format such as: sx, 0, 0, 0, sy, 0, 0, 0, sz https://en.wikipedia.org/wiki/Scaling_(geometry) https://www.google.com/search?q=scale+matrix How to perform operation with a such matrix? Multiple columns by vector [x,y,z] element and add them together in the same row.. e.g. x' = sx * x + 0 * y + 0 * z; y' = 0 * x + sy * y + 0 * z; z' = 0 * x + 0 * y + sz * z; Because matrix had 0 in some columns and rows (most of them!), this can be much simplified without matrix multiplication to just: x' = sx * x y' = sy * y z' = sz * z From 9 equations (3x3 matrix with 3x vector elements, 9) we can have 3. From 16 equations (4x4 matrix with 4x vector elements, 16) we can have 4. For rotation it is not so simple. E.g. rotation in Y axis: Matrix 3x3 will have format e.g. cos( angle), 0, -sin( angle ), 0, 1, 0, sin( angle ), 0, cos( angle ), Or something like that (+/- sinuses and cosines) https://en.wikipedia.org/wiki/Rotation_matrix For translation you need 4x4 matrix with format: 1, 0, 0, tx, 0, 1, 0, ty, 0, 0, 1, tz, 0, 0, 0, 1, https://www.google.com/search?q=translation+matrix Matrix operations are 1) easy for computers to perform in parallel 2) slow down the whole process (during plain scaling and/or translation) 3) speed up operations if they were complex are they were merged together 4) make it more readable for humans who needs to review them. The matrices can be "multiplied" by other matrices, yielding matrices that can be used for the final vector transformation. Which can simplify the entire vector transformation process. https://www.google.com/search?q=matrix+combine https://www.google.com/search?q=matrix+merge MMX means Matrix Math Extensions or Multi Media eXtension. Pentium CPU ~ 26 years ago. SSE means Streaming SIMD Extensions. They are basically operations on matrices and vectors. Multiply 2, 3 or 4 elements in an array and/or add them together in the one CPU operation. If you write things the right way, MMX and/or SSE/SSE2, etc. will be automatically activated by the compiler and used, and you will be able to increase the performance of your code... or you can write your own MMX/SSE/SSE2+/AVX CPU code.. https://en.wikipedia.org/wiki/Advanced_Vector_Extensions (AVE = "Advanced Vector Extensions" > SSE > MMX) i.e. AVE is SSE on "steroids".. and SSE is MMX on steroids... ..now depreciated by GPUs..
  17. ..unfortunately those good times are over..
  18. ..I would guess without even bothering microscope.. I would just use my lie detector..
  19. Does he have free will or is he predestined to utter such words..? Look at Swansont's minature - "resistance is futile"..
  20. ..and they never look the same as they did before, so every time you look at a nail like that, you are reminded of an accident from the past.. Accident, is the most common way to lose nails..
  21. The number of bizarrenesses increases with each generation.. The apparent result of living too well..
  22. Are you able to explain your thought path that led you to such extraordinary conclusions.. ?
  23. ..or you were predestined to say such words.. Philosophical discussions can be shortened to the statement "I know that I know nothing".. If one needs brain exercises, one should start creating algorithms, i.e. solving solvable problems, rather than wasting (precious human life) time on unsolvable ones..
  24. Unwise. Used socks and shoes should not be given, exchanged, purchased or sold to other people - in this way it is very easy to get infected with onychomycosis and/or foot fungus. Onychomycosis ends with the old nail falling off and a new one growing in its place.. It takes many months..
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