What is Bit: Definition and 398 Discussions

The bit is the most basic unit of information in computing and digital communications. The name is a contraction of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as either "1"or"0", but other representations such as true/false, yes/no, +/−, or on/off are commonly used.
The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program. It may be physically implemented with a two-state device.
The symbol for the binary digit is either "bit" per recommendation by the IEC 80000-13:2008 standard, or the lowercase character "b", as recommended by the IEEE 1541-2002 standard.
A contiguous group of binary digits is commonly called a bit string, a bit vector, or a single-dimensional (or multi-dimensional) bit array.
A group of eight binary digits is called one byte, but historically the size of the byte is not strictly defined. Frequently, half, full, double and quadruple words consist of a number of bytes which is a low power of two.
In information theory, one bit is the information entropy of a binary random variable that is 0 or 1 with equal probability, or the information that is gained when the value of such a variable becomes known. As a unit of information, the bit is also known as a shannon, named after Claude E. Shannon.

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  1. C

    Max Input Change for 1 Bit Output in 12-Bit ADC: 0.50037V

    Homework Statement The full range input of a12-bit, successive-approximation type ADC is 1 volt. Determine: a) the maximum input change required to give a one bit change in output of the ADC Homework Equations None The Attempt at a Solution The ADC is 12 bit, so it will produce a...
  2. ZapperZ

    If you look a bit foreign, don't do math on a plane

    This is way too stupid to make up: https://www.washingtonpost.com/news/rampage/wp/2016/05/07/ivy-league-economist-interrogated-for-doing-math-on-american-airlines-flight/ Zz.
  3. dbcoopersurviv

    I A bit confused about Schrödinger's cat

    I am certain this has been asked before many times before since the cat in the box first did not come out, and I am just overlooking it. And I am using the cat in the box for the exact purpose it was orginally created as I understood, to simplify the concept to its very base pieces to allow...
  4. S

    Basic 1-d dynamics with a bit of calculus.

    Homework Statement A 500 kg boat moves with an initial speed of 20 m/s turns off it engine and slows down due to the drag force. If this force has magnitude F= 15.3v^2 find the boat speed after 12 seconds.Homework Equations ∑F = ma dv = adt The Attempt at a Solution taking the side opposite...
  5. V

    Help understanding Shannon entropy

    Hi I'm having some trouble understanding Shannon entropy and its relation to "computer" bits (zeros and ones). Shannon entropy of a random variable is (assume b=2 so that we work in bits) and everywhere I've read says it is "the number of bits on the average required to describe the random...
  6. Geek007

    Bit rate, bit interval vs frequency, time period

    can we use frequency and time period terms for digital signals or we have to use bit rate and bit interval terms for digital signal. in simple words,
  7. nmsurobert

    How Many Photons Are in Each Bit of a 10 Gb/s Optical Signal?

    Homework Statement An optical communication system operating at λ = 1550nm is transmitting pulses at 10 Gb/s. The magnitude of the optical pulses is the same. Calculate the number of photons received within each bit. Assume that the received average optical power is 10 mW. Homework...
  8. S

    Tachyons, the Double Slit Experiment, and a bit of Fiction

    Hello, All! I'm writing a bit of fiction, and as a newcomer to the world of Quantum Physics, I thought I'd clarify a few concepts here, to avoid lapsing into technobabble. I'm trying to make something along the lines of the film Primer, which tries to incorporate as much realism as possible...
  9. MidgetDwarf

    A bit of confusion regarding instructions

    Mentor note: moved the thread to the homework forum So I was given a few problems to take home, to complete by the professor. My question is not regarding how to solve the problems but rather, if I understand the instructions. We are given the following instructions. Find the general...
  10. CentrifugalKing

    Need a bit of help -- Pulley accelerated by a force....

    Homework Statement A pulley, with a rotational inertia of 1.5✕ 10-3kg·m2 about its axle and a radius of 10 cm, is acted on by a force applied tangentially at its rim. The force magnitude varies in time as F = 0.50t + 0.30t2, where F is in Newtons and t in seconds. The pulley is initially at...
  11. alexmahone

    MHB Finding the Number of Bit Strings with 8 Zeros and 10 Ones

    How many bit strings contain exactly eight 0s and 10 1s if every 0 must be immediately followed by a 1?
  12. A

    Problems building a 1 bit / 2 to 1 Multiplexer

    First let me just I'm a total newbie to electronics, but I would like to progressively learn how computers work by building the little components with the small parts, and then work up to the ICs once I understand how to make rudimentary versions. I'm trying to make a 1-bit multiplexer out of...
  13. Mr.Robot

    Interfacing 8 Bit ALU on LCD ( fpga kit )

    I have the code of 8 bit ALU and code of lcd controller mounted on spartan 3E fpga kit. but i am unable to sync the program. Please help me with it! Thank you!
  14. davenn

    Tuesday Giggle - a little and cute bit of audio humour

    a fun play on words
  15. I

    Post-grad feeling the tiniest bit lost

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  16. Kior

    Would anyone explain the solution a little bit to me?

    I am preparing for my math probability class next semester. There is question: Calculate E(x3µσ) Would anyone explain the solution in the picture a little bit to me? 1.Why is the step hold? Is there a formula or something that i can calculate E[X-µ]n? 2.Why is the fourth step hold? Where is...
  17. G

    MHB Bit Masking: How to Manipulate Bits in Binary Numbers

    Hey Guys, can i have a hand with this question. I just want to know if what I did was right. Bit masking has a task. They are used in order to access specific bits in a byte of data. 1) Using the 8-bit binary number “1001 1101”: Turn off the 2 bits (masking bits to 0) on each side, and then...
  18. F

    Combination formula on dice and bit errors

    When the learning combination formula the formula nCr is usually derived using a deck of cards. There are n=52 different card. If you choose r number of cards, each is different so you basically start with n!/(n-r)! , then because the order is unimportant multiply by 1/r!. This explanation is...
  19. K

    Difficult time brazing drill bit to ultrasonic horn

    I have an ultrasonic drill, and need to attach a stainless steel drill bit (hollow tube) to a hardened steel horn. For anyone unfamiliar with ultrasonic drilling, please take a look at the following illustration with instructions for mounting the drill bit...
  20. F

    Is there such thing as one bit of information?

    The smallest unit of information is a bit, which has two possible states. Yet don't you also have to specify the location of this information? So in a 4d world we're talking about 4 + 1 = 5 degrees of freedom, or 5 bits of information to code for just the one bit. So is there really such...
  21. S

    The 1904 plane of the Wright Brothers a bit strange

    Something strange regarding the 1904 plane (Flyer No 2) built by the Wright Brothers I am looking for an as simple as possible mathematical model that can explain how it really worked. In 1904, the Wright Brothers started to test a new plane, Flyer II, somewhere near Dayton, Ohio where they...
  22. G

    Frame Synchronisation via Modified Approach to Bit Insertion

    Homework Statement I am currently embarking on a project which requires me to design a system where I can transmit voice over a distance, by inputting an analog voice signal on one end and then recovering the voice which I input on the transmitting end at the receiving end. The general design...
  23. K

    What is the correct answer for the 4 bit magnitude comparator homework?

    Homework Statement Homework EquationsThe Attempt at a Solution As long as A = 1, its true, So options (A) and (C) are wrong. My ans is (E). Right?[/B]
  24. nomadreid

    Are the two definitions of "bit" compatible?

    First, I am not sure that this is the right place for this post, because earlier Physics Forums broke up the "computing and technology" into several subheadings, such as information science as opposed to hardware, and so forth, that I don't see anymore. Anyway, so here is an elementary question...
  25. DaveC426913

    What is the purpose of this extra bit on my pocket charger?

    I recently bought this pocket charger for my phone. Simple device, power in, power out. But it has this extra bit whose purpose I cannot figure out. Ideas?
  26. C

    Comparing 2-Bit Numbers with a Single Decoder and Standard Logic Gates

    < Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Is there a way to create two bit numbers comparator using one 2 to 4 decoder and standard logic gates?
  27. W

    Someone know a bit about Generators? (windmill project)

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  28. Coffee_

    [Intro QM] A bit confused on spin of system notation

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  29. J

    Would a pure diamond drill bit ever get dull?

    If a drill bit that was cut out of a single large diamond were made, would it last forever, assuming it was never used to drill through diamond and was never exposed to a laser? Would it ever get dull or break?
  30. interhacker

    Programs A Bit of Advice on Major Selection

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  31. Silicon Waffle

    Why Does Bit Shifting in Win32 API and C# BitConverter.ToInt32 Act Differently?

    In Win32 API, I see the define macro MAKEWORD #define MAKEWORD( h, l ) \ ( ( ( WORD )( h ) << 8 ) | ( BYTE )( l ) ) Why does it make a shift of 8 bits ? In C#, they have a BitConverter.ToInt32, which performs something similar to this Makeword and I use this 8 bit shift and it works...
  32. C

    What Is Total Parity of Bits?

    Below is the extraction from quantum computer book, but I think my question is related to classical computing; "Now let us generalize from one to multiple qubits. Figure 1.6 shows five notable multiple bit classical gates, the AND, OR, XOR (exclusive-OR ), NAND and NOR gates. An important...
  33. dkotschessaa

    A bit of encouragement needed Academic probation

    I rarely post these pathetic types of threads, but I kind of need to right now if you all don't mind. For those that don't know me... now 38 years old, first year of grad school for mathematics. I started undergrad at 33. I am married, have A.D.D. and a somewhat busy life, but I'm very...
  34. P

    Mechanics and a bit of fluids (mech).

    Hi, This problem has been driving me mad! Can anyone simplify the physics of this problem? Because I can't solve due to to many unknowns. Question ref: Engineering Materials, Benham, Crawford & Armstrong. Please refer to attachments.
  35. L

    Need clarification regarding carry and overflow bit

    I'm trying to understand carry & overflow bits. Carry seems pretty easy - If I'm not mistaken, if you carry on your last bit into a bit that you don't have, the carry flag is set to 1. For overflow, I referred to another previous thread on here, of which one of the posters recommended the...
  36. A

    Need a bit of help understanding voltage drops

    2 Questions... (Iam sort of new so please forgive if what I ask don't make any sense.) #1. If I am receiving an 1000v output from an experimental electric device and I only need around 700v what happens to the 300v of electricity that's left after I take only what I need? #2.Can someone tell...
  37. T

    Designing a Parity Bit Circuit for Data Transmission

    Homework Statement A parity bit will be 0 if the data contains an even number of 1’s and it will be 1 if the data contains an odd number of 1’s. If during transmission a 1 is changed to a 0 or vice versa, then the parity check at the receiver will fail. Determine the parity P for 4–bits of...
  38. B

    Understanding n-bit and m-bit Numbers

    Hi guys, I sure this is an astonishingly dumb question, but I am new to embedded systems, so don't be too harsh. I am taking embedded systems in final year at uni and working through some introductory tutorial sheets. One question asks; -If two n-bit numbers are added together, what memory...
  39. STEMucator

    IEEE Floating Point, 64 Bit: How are Exponents Translated into Ranges?

    Homework Statement This is not a homework problem, but rather a concern I had while reading. Not sure where I should've put this thread. Homework Equations The Attempt at a Solution I was reading about how integers/floating point numbers were stored in a computer. For an n-bit word, the...
  40. M

    A Bit Confused About Polar Basis Vectors

    Let me say from the beginning I'm not talking about the non-coordinate unit vectors for polar coordinates. I'm talking about basis vectors. Let me just ask it as boldly as possible: how does one use these basis vectors in order to describe a vector? I know they are different at every point, so...
  41. J

    What are the ratios of width and length for these two rectangles?

    I've indicated two rectangles. Can peeps tell me what they get for the ratio of widths? And then the ratio of lengths? Thanks. rectangles.JPG
  42. T

    16 bit sigma delta ADC question

    Hi every one, I am examining a prototype device that is designed to analyse current from an electrochemical O2 sensor (current source), The sensor will output 1.124 uV per PPM (cross 47 ohms @0.023 uA), and has acuracy of +- 2 PPM, with max 1000 PPM. it ueses 16 bit Sigma Delta ADC with...
  43. Q

    (A bit for fun) Putting a Human in Superposition

    Putting a Human in Superposition I recognize the practical aspects of this would be absurd, but I must admit the premise of what it would take to put a human in a superposition of states is an amusing thought exercise and has some relevance towards me understanding actually in what scenarios QM...
  44. C

    Derivatives, and a little bit of linear approxim

    Homework Statement I have to find the deriv of ##f(x)=xArctan(x^{3})## I just need an explanation of how the arctan works... So I understand the rest, but just the deriv of arctan itself is confusing for me. So the derivative of ##arctan(x)## just in general is ##\frac{1}{1+x^{2}}## But if...
  45. T

    Attempting to learn a little bit of Quantum physics at 17

    I'm 17 years old and plan to study theoretical physics at university. I want to try and learn a bit of quantum physics just because it interests me; got to spend the summer doing something! Sadly I only have a AS level understanding (including FP1) of maths so can anyone recommend any resources...
  46. allamsetty

    Multi Scale simulations on windows 7 32 bit Computer

    I am Post Graduate in Physics and working as a researcher in Non Destructive testing. I have heard about multi-scale simulations and its applications to material modelling. Iam intersted in learning mutiscale simulations for materials modelling. can anyone provide me links that would let me...
  47. A

    ISC Bit Setting for Interrupt Service Routine

    I'm setting up an interrupt service routine, but I'm unsure which ISC bit setting I should use. ISC bit settings: ISCx1 ISCx Description 0 0 Low level of INTx generates an interrupt request 0 1 Any logic change on INTx generates an interrupt request 1 0 The falling edge of INTx...
  48. C

    Why Does Gauss's Law Use Cylinder Circumference Instead of Area?

    Homework Statement So I was looking at this site reading up again on Gauss's Law and was a tad confused http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elecyl.html 1st thing on the page... Homework Equations The Attempt at a Solution It states that the electric flux will just be the...
  49. C

    Why does more bandwidth means higher bit rate in digital transmission?

    I'll start with what I do know: Shannon Law gives the theoretical upper limit C_{noisy}=B*log_{2}(1+\frac{S}{N}) if S = N, then C = B As N→∞, C→0 As N→0, C→∞ Nyquist Formula says approximately how many levels are needed to achieve this limit C_{noiseless}=2*B*log_{2}M (If you do not use enough...
  50. Y

    Is There a 64-Bit Version of Microsoft Security Essentials for Windows 7?

    I just got my Win 7 64 bits computer. I went to Microsoft site to download the Security Essential. But when I tried to install the program, it said it's for a 32 bit computer and I need to get the 64 bit one. I went on MS site and looked all over, typed in "64 bit Security Essential". But I kept...
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