Скачать или смотреть Digital Lecture 02 Binary Logic gates

Number Systems
I. Decimal number system : The familiar decimal number system has base or radix 10. It referred to as base 10 because it uses ten digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These digits are referred to as the coefficients of the decimal system. Thus, in the decimal system the coefficients are multiplied by the appropriate powers of 10 to form a number.
II. Binary Number System: Binary is a number system used by digital devices like computers, cd players, etc. Binary is Base 2 unlike our counting system decimal which is Base 10 (denary). In other words, Binary has only 2 different numerals (0 and 1), unlike Decimal which has 10 numerals (0, 1, 2,3,4,5,6,7,8 and 9). Here is an example of a binary number: 10011100.
The bit on the far right (in this case a zero) is known as the Least significant bit (LSB), and the bit on the far left (in this case a 1) is known as the Most significant bit (MSB). For example: 1012 is a binary number and 10110 is a decimal (denary) value.
III. Octal Number System: Although this was once a popular number base, especially in the Digital Equipment Corporation PDP/8 and other old computer systems, it is rarely used today. The Octal system is based on the binary system with a 3-bit boundary.
IV. The Octal Number System: Uses base 8 Includes only the digits 0 through 7 (any other digit would make the number an invalid octal number).
V.Hexadecimal Number System: Binary is an effective number system for computers because it is easy to implement with digital electronics. It is inefficient for humans to use binary, however, because it requires so many digits to represent a number. The number 76, for example, takes only two digits to write in decimal, yet takes seven digits to write in binary (1001100). To overcome this limitation, the hexadecimal number system was developed. Hexadecimal is more compact than binary but is still based on the digital nature of computers.