# Bit

A bit (a contraction of binary digit) is the basic capacity of information in computing and telecommunications; a bit can have the value of either 1 or 0 (one or zero) only. These attributes may be implemented, in a variety of systems, by means of a two state device.

In computing, a bit can be defined as a variable or computed quantity that can have only two possible values. These two values are often interpreted as binary digits and are usually denoted by the numerical digits 0 and 1. The two values can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/), activation states (on/off), or any other two-valued attribute. 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. The length of a binary number may be referred to as its "bit-length".

In information theory, one bit is typically defined as the uncertainty 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.

In quantum computing, a quantum bit or qubit is a quantum system that can exist in superposition of two bit values, "true" and "false".

The symbol for bit, as a unit of information, is either simply "bit" (recommended by the ISO/IEC standard 80000-13 (2008)) or lowercase "b" (recommended by the IEEE 1541 Standard (2002)).

### Other articles related to "bit, bits":

Bit - Other Information Units
... the natural digit also called a nat or nit and defined as log2 e (≈ 1.443) bits, where e is the base of the natural logarithms and the dit, ban, or hartley, defined ... Conversely, one bit of information corresponds to about ln 2 (≈ 0.693) nats, or log10 2 (≈ 0.301) hartleys ... a binit as an arbitrary information unit equivalent to some fixed but unspecified number of bits ...
UNIVAC 1105
... The UNIVAC 1105 had either 8,192 or 12,288 words of 36 bit magnetic core memory, in two or three banks of 4,096 words each ... Fixed-point numbers had a one-bit sign and a 35-bit value, with negative values represented in ones' complement format ... Floating-point numbers had a one-bit sign, an eight-bit characteristic, and a 27-bit mantissa ...
Manchester Code - Description
... Extracting the original data from the received encoded bit (from Manchester as per 802.3) original data XOR clock = Manchester value 0 ... Summary Each bit ... Manchester code always has a transition at the middle of each bit period and may (depending on the information to be transmitted) have a transition at the start of the period also ... The direction of the mid-bit transition indicates the data ...
Modified AMI Code - Zero Code Suppression
... ensure a minimum density of marks was zero code suppression a form of bit stuffing, which set the least significant bit of each 8-bit byte transmitted to a 1 ... This bit was already unavailable due to robbed-bit signaling.) This avoided the need to modify the AMI code in any way, but limited available data rates to 56,000 bits per second per DS0 voice ... with the G.703 and ISDN PRI standards which called for 64,000 bits per second, led to this system being superseded by B8ZS ...