What is "bit"
Bit is the smallest unit of information that can be stored or transmitted. Used in Computation and Information Theory. A bit can assume only 2 values, for example: 0 or 1, true or false.
Although computers have instructions that can test and manipulate bits, they are usually designed to store instructions in multiple bits, called bytes. At first, byte had variable size but currently has eight bits. Eight-bit bytes are also called octets.
There are also terms to refer to bit multiples using prefixed patterns, such as Quilobit (kb), megabit (Mb), Gigabit (Gb), and Terabit (Tb). Note that the bit notation uses a lowercase "b" as opposed to the byte notation that uses a uppercase "B" (kB, MB, GB, TB).
Physically, the value of a bit is generally stored as an electrical charge above or below a standard level in a single capacitor within a memory device. But, bits can be represented physically by various means.
The means and techniques commonly used are: For electricity, as already mentioned, by light (in optical fibers, or in optical disc readers and recorders for example), by electromagnetic waves (wireless network), or also by magnetic polarization (hard disks).
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