Bit Definition and 398 Threads

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. N

    Looking For Academic Guidance - I'm struggling a bit

    Looking For Academic Guidance -- I'm struggling a bit Hello, I am currently hoping to obtain a physics degree, but I am just a little shaken up by my last two tests I took in Gen Phy 2 E&M. I try really hard and would go as far to say that no one in my class works as hard as I do to learn and...
  2. B

    16 Bit Assembler Vertical Bar Loop

    Homework Statement Create a program that displays a vertical bar character ‘|’ moving left to right in 79 positions across the screen, then back right to left across the screen. Homework Equations (16 bit Assembler) The Attempt at a Solution .model small .stack 100h .data...
  3. B

    Understanding 32 Bit PCI Slots with a Bandwidth of 1133MBps

    The 32 Bit PCI Slots have a Bandwidth of 1133MBps. And I know they connect to the Southbridge BUSS. But if you have three PCI Slots and you have a FAX Card in one and a Graphics Card in another. And they both are working at the same time am I right the 1133MBps Bandwidth will be split...
  4. S

    Python Having some trouble with a little bit of Python Homework:

    Homework Statement The problem shows as follows: An arithmetic progression is a sequence of numbers in which the distance (or difference) between any two successive numbers if the same. This in the sequence 1, 3, 5, 7, ... , the distance is 2 while in the sequence 6, 12, 18, 24, ... , the...
  5. D

    Fed up with Visio - Modify things a bit and the whole diagram breaks

    I have been using Visio for a few days now and I'm frustrated because I can't edit my UML sequence diagram a bit without the whole thing falling apart. Say I have it already nicely done and I want to add an alt box. When I shift the whole thing down, some of the activation bars and message...
  6. N

    What Is the Maximum Value of f(x, y) = x + y Given the Constraint xy = 16?

    Homework Statement Find the maximum value of the function f(x, y) = x + y subject to the con- straint xy = 16, x > 0, y > 0. Homework Equations f(x, y) = x + y xy = 16 The Attempt at a Solution I attempted this first using substitution, then using LaGrange multipliers. Both...
  7. M

    MHB We mathematicians are all a bit crazy

    The title of this thread is a famous _ and apropriate _ quote about mathematicians. As per request it was changed so that this thread serves the purpose of sharing crazy mathematician's stories (observation: the apostrofe is before the s ;) ) I'm sure many of you heard this before, but I love...
  8. D

    Designing a 4-Bit Multiplier using Basic Digital Logic Components

    Homework Statement Begin the design of the multiplier by adding more detail to the block diagram. The parts available for your design are • D Flip-flops (74LS74A) • 1 4-bit Up/Down Counter (74LS169) • 1 4-to-1 MUX • 1 4-bit Adder (74LS283) • 2 4-bit Parallel Shift Registers (74LS194A)...
  9. O

    Shannon entropy - use to calculate the bit needed to encode a symbol

    To encode a symbol in binary form, I need 3 bits ,and I have 6 symbols. So I need 6*3=18 bits to encode "We are" into binary form. As shown in http://www.shannonentropy.netmark.pl/calculate My question: 3 bits to encode one then I have to use 16 bits, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. How to...
  10. L

    Calculating Rotational Inertia (A Bit of Confusion)

    Hey all, Perhaps this is a bit stupid... I'm familiar with the normal procedure of calculating rotational inertia (using integration, parallel axis theorem, etc.). However, I had a confusing thought: if the center of mass of a body is the point at which you can treat as all of the mass being...
  11. S

    Bit Specific Assembly Definitions

    I have an example given in the textbook that defines port A bits 5 as PA5 equ 0x40004080. Port A is 0x40004000, and the first 7 bits are for data. I do not see how bit 5 is 0x80. I figured that would be bit 7 and bits 5 would be 0x20. We use ARM assembly language for LM4F120H5QR microcontroller.
  12. I

    Programs Physics Majors Internships (and a bit more)

    Hello there PF! Recently I've been trying to decide between engineering and physics as a college major, and I came across this forum and thought I might as well see what you guys had to say. As you can tell from the title, I'm particularly concerned with what internship opportunities are...
  13. S

    MHB Addition with eight bit 2's complement numbers. [Check my Work]

    Perform the following operations involving eight-bit 2's complement numbers and indicate whether arithmetic overflow occurs. 1) 01110101 + 11011110. So I have a +Positive + a -Negative number. So I just added normally, and got the result of 01010011. I realized before I started the problem I...
  14. S

    MHB Adding 8 bit 2's complement numbers.

    I don't understand something. Perform the following operations involving eight-bit 2's complement numbers and indicate whether arithmetic overflow occurs. If I have 01110101 +11011110 I know that the second term is negative because there is a 1 in front. Now, because it is negative do...
  15. C

    Decimal Values of 8-Bit Bit Patterns

    Homework Statement Find the decimal values for the following 8-bit bit pattern A)00000010 in excess 128 representation B)10000010 in excess 128 2's complement representation C)10000010 in excess 128 representation Homework Equations Binary 2's complement The Attempt at a Solution...
  16. M

    This paper looks a bit sketchy.

    http://arxiv.org/abs/physics/0511172v2 "Instantaneous Interaction between Charged Particles" by Wolfgang Engelhardt Submitted to Annales de la Fondation Louis de Broglie Has this paper undergone a good process of peer review? It seems in violation of Special Relativity.
  17. Ascendant78

    A bit frustrated regarding my studies and progress.

    I'm taking Physics 1 this semester and am a bit frustrated. For starters, our instructor is not that great. The average grade for our first exam was a 68. I was one of only two students to make an A on the exam. However, despite doing well on that first exam, I don't feel like I am learning...
  18. S

    Exam: Detecting Errors in Bit Strings

    1. The question The following message was originally transmitted with odd parity in each short bit string. In which strings have errors definitely occurred? 11001 11011 10110 00000 11111 10001 10101 00100 01110 2. The attempt at a solution It says that it is transmitted with odd...
  19. L

    The most ridiculous bit of pseudoscience

    that you've ever heard? Was watching an old episode of QI the other night and came across drapetomania, which is utterly shocking. Have heard a lot of nonsense being passed off as science in the past, what's the most ridiculous you've heard?
  20. micromass

    Challenge VII: A bit of number theory solved by Boorglar

    This new challenge was suggested by jostpuur. It is rather number theoretic. Assume that q\in \mathbb{Q} is an arbitrary positive rational number. Does there exist a natural number L\in \mathbb{N} such that Lq=99…9900…00 with some amounts of nines and zeros? Prove or find a counterexample.
  21. F

    A general Master's or a bit more specialized?

    I'm going for a masters in chem eng, and aside from my 6 general courses, I can also take 4 electives. I'd like to take nanotechnology courses, since that is a field that I am very interested in (but isn't my only option). Do you think this is worth it to "specialize" like this? Since I have the...
  22. S

    Little bit of help for science fair project please

    Little bit of help for science fair project please! Hi guys, I am 13 years old and I am a new member on this forum and I need help with a science fair project. For my project I am showing how companies make tablets so I need to learn how to make a tablet. I did some research but some of the...
  23. S

    How Do You Start Designing a 4-Bit ALU with Multisim?

    Hallo guys , I am first year electrical Engineer Major & we are asked to design and simulate using Multisim a small ALU , The ALU is a 4-bit digital circuit that performs addition, subtraction, ANDing, ORing, complementing, XORing, XNORing and comparison. The ALU also outputs if the answer is...
  24. T

    A bit of confusion on a simple thermodynamics problem.

    Homework Statement A house with floor space of 2000 ft^2 and average height of 9 ft is heated from an average temperature of 50 degrees F to 70 degrees F. Determine the amount of energy transferred in the house assuming: a) The house is air tight. b) Some air escapes through the cracks as...
  25. E

    Expressing probability of bit error

    Homework Statement I need to the probability of bit error in terms of integrals and terms of conditional probabilities. Its a bipolar system using threshold detection https://www.physicsforums.com/attachment.php?attachmentid=58542&stc=1&d=1367888259 Homework Equations probability of...
  26. H

    Can a Photon be thought of as a bit?

    A photon is emitted and then absorbed. And since a photon travels at the speed of light, time does not exist. So that should mean that a photon is in either a state of emission or a state of absorption. Doesn't that make a photon a type of bit? Furthermore - if there is no time involved...
  27. E

    Dipole - the calc. seems a bit illogical though correct

    I was reading the calculation for calculating the electric field due to a dipole at any point P at a distance x from the center of the dipole. the way they have written the calc. seems a bit illogical they have broken p into two components pcosθ and psinθ and applied E = kp/r3 Now...
  28. H

    Reason for various drill bit speed for different drill bit size?

    In the shop I was taught that , for a larger drill bit, use slower speed, vice versa I would like to know for what reason this is? I understand by using slower speed for bigger drill bit and vice versa, we can maintain the same/similar velocity at the outer edge of the drill bit, (omega *...
  29. N

    Does an Apple Make a Sound if No One is Around to Hear It?

    An apple falls from a tree. Nobody is around ( no living being is around). Would there be sound?
  30. A

    Build 1 bit comparator using 2 to 4 decoder?

    build 1 bit comparator using "2 to 4" decoder?? Homework Statement The Attempt at a Solution worked out truth table: A B A>B A<B A=B 0 0 0 0 1 0 1 0 1 0 1 0 1 0 0 1 1 0 0 1 prty sure that's right. just need part B...
  31. W

    Decimal to Binary 32 bit signed conversion

    Homework Statement Convert -89 to 32 bit representation (2-complement for negative numbers) my answer does not agree with calculated answers from multiple conversion sites. Homework Equations The Attempt at a Solution to get the exponent i figured out the closest 2 exponent to...
  32. V

    I need a bit of a pep talk. I'm having a rough semester so far.

    So a quick bit of back ground. I'm a 28 year old returning to school after a very long haitus (I only graduated 5th grade because my parents were religious wingnuts that insisted the end was nigh, and so took me out of school and made me study the bible instead.) I worked as a construction...
  33. G

    Controller Area Network (CAN) bit stuffing

    I was going through an article on CAN bus in Wikipedia & was stuck at the point where bit stuffing is explained. CAN is an asynchronous bus. They implement NRZ (Non-Return-To-Zero) encoding. To enable the receiver to correctly read the messages, continuous resynchronization is required...
  34. O

    Programs A bit depressed searching PhD opportunities

    Hi All, Maybe my first post is a bit sad/depressive, but I need some advice. I have finished recently my MSc. degree in Space Technology & Space Sciences. I have a BSc. in Physics as well and I'm considering to do a PhD. with a challenging topic. However, I'm unlucky. Since last...
  35. M

    Fortran Fortran 90, changing 8 bit stream into a 10 bit one

    Hello, I'm having a bit of trouble converting an 8 bit stream into a 10 bit one. First i create intvalbin8, a Nx8 zero/one array where N is the byte length of the input data: (6198 is the header offset factor) j=1 do while (intvalout(i).gt.0)...
  36. L

    Design 8 bit adder: Steps & Tips

    Hi I already created a 4 bit adder but for my assignment I need an 8 bit one. Is it correct if I design to separate 4bit adders and connect their outputs (Cout) with an AND gate? 4 bit adder: https://www.dropbox.com/s/ao60s6dgtrnhal3/4bit%20adder.PNG
  37. J

    Hi all,Im having a bit of trouble understanding the concept of

    Hi all, Im having a bit of trouble understanding the concept of viscosity in the scenario of a fluid between two plates, with one moving and one being stationary: what is the relevance between the viscous force of the fluid and the shear stress on the fluid given by mu(du/dy) ?
  38. P

    Why Is My Physics Professor Giving Contradictory Advice?

    HI I'm new here. I've been having a little bit of trouble with a few of my physics problems. It seems like very basic stuff. I went to my professor's office hours and he didn't help me. He told me the wrong stuff, and when I emailed him back, he said different stuff. 1) An ideal monatomic...
  39. P

    C/C++ [C/C++] need a bit of help making a simple search engine.

    Hi, new to the forum, it is a really spiffy place. I'm not really much of a programmer, but I have an interest in it and kind of like to piddle around with programming. I am learning C and C++ mostly by doing, browsing books, and asking dumb questions of people who know a lot more about it than...
  40. D

    Designing a 2-Bit Half Adder: How to Add Two 2-Bit Numbers Without Carry?

    I had a cpre exam last night and this was the last question. Can some one tell me the answer, I'm curious if I got it right or not. The part that tripped me up was a 2 bit "half adder". I assumed I wasn't supposed to use a full adder. So I'm not sure what to do with the carry from the first...
  41. O

    I'm a bit concerned for my future.

    Hello, I'm a third year ME student, and I seem to have hit a major wall. I've been doing okay for a while, but now I'm struggling much more than I have been in the past. My GPA is dropping before me and even when I work hard, my exam grades tank. I'm a terrible test taker, and I feel it is...
  42. P

    Electrostatics question. just need a bit direction.

    I was trying to solve this one, but couldn't come up with any way to start. In 1959 Lyttleton and Bondi suggested that the expansion of the Universe could be explained if matter carried a net charge. Suppose that the Universe is made up of hydrogen atoms with a number density N, which is...
  43. M

    How High Does Henry Bounce on the Trampoline?

    The question is: Henry is bouncing on a trampoline, using the given data below, calculate the height at which Henry will bounce to from his lowest position. Lowest position: -0.50m Henry's Mass: 75kg upward acceleration: 13.3 m/s^2 upward force: 1750N downward force: 750N Net force...
  44. N

    Comp Sci Find primes using sieve of erasthothenes by way of bit arrays in C++

    Hey. I have to create a program in C++ to calculate the number of prime numbers up to a specified number. I also have to print out the first and last 5, but I'll cross that bridge when I come to it. I can do this fine with integers, but we have to do it where each slot in an array represents...
  45. C

    Probability of 0 bit in ASCII text files

    text files consists of 0&1 bits. But in ASCII, Most Significant Bit(MSB) is 0, so we have more 0s than 1s. Assume that we draw bits at random. Question: What is probability of drawing 0 in 2nd time, given 1st drawing was 0? My Analysis: From bayes formula, Pr(0) = 1/8*1 + 7/8*1/2 = 9/16, so...
  46. X

    Binary subtraction question using 2's complement method and an 8 BIT

    Homework Statement 00001101 bin * 00001000 bin -----------------------------------Homework Equations It's a binary subtraction question using 2's complement method and an 8 BIT register.There's no equation than,I guess. The Attempt at a Solution 11111111 <--1's "carried...
  47. R

    Why Does My Calculated Answer Differ from the Marked One on a Physics Test?

    While I was studying I downloaded and printed a previous old test which already answered I tried to re-solve the questions by myself but there is one question made me confused as I get a result mentioned in the options but the marked answer is different. I am talking about question 3 in the...
  48. Psinter

    Can this 4 bit adder be further simplified?

    Hello, I'm new to logic circuits and I was making a 4 bit binary adder and I thought I could maybe simplify it. However, I can't find anything simpler than what I already got. What I wanted to know is: is my circuit already in its most simple form or am I making something wrong in my attempts to...
  49. DeusAbscondus

    LaTeX Could someone tell me what is wrong with this bit of latex

    $\left( \text{The ones you see were done by use of} $ $\text{perpendiculars}\r) $$$\left(\text{The ones you see were done by use of perpendiculars}\right)$$
  50. B

    Multiplying two N bit signed numbers together

    Homework Statement Determine the number of bits needed to represent the range of results obtained when two N bit signed numbers are multiplied together. Homework Equations None. The Attempt at a Solution I considered the case when N = 3, i.e. a 3 bit signed number. The values...
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