《电气工程与自动化专业英语 教学课件 ppt 作者 王伟 3》由会员分享，可在线阅读，更多相关《电气工程与自动化专业英语 教学课件 ppt 作者 王伟 3（25页珍藏版）》请在金锄头文库上搜索。
1、3.1 Introduction,A circuit that employs a numerical signal in its operation is classified as a digital circuit. Computers, pocket calculators, digital instruments, and numerical control (NC) equipment are common applications of digital circuits. Practically unlimited quantities of digital informatio
2、n can be processed in short periods of time electronically. With operational speed of prime importance in electronics today, digital circuits are used more frequently.1,3.2 Digital Number Systems,3.2.1 Binary Number System 3.2.2 Binary-coded Decimal(BCD) Number System 3.2.3 Octal Number System 3.2.4
3、 Hexadecimal Number System,3.2.1 Binary Number System,Electronic digital systems are ordinarily the binary type, which has 2 as its base. Only the numbers 0 or 1 are used in the binary system. Electronically, the value of 0 can be associated with a low-voltage value or no voltage. The number 1 can t
4、hen be associated with a voltage value larger than 0. Binary systems that use these voltage values are said to have positive logic. Negative logic, by comparison, has a voltage assigned to 0 and no voltage value assigned to 1. Positive logic is used in this chapter.,3.2.2 Binary-coded Decimal(BCD) N
5、umber System,When large numbers are indicated by binary numbers, they are difficult to use. For this reason, the Binary-Coded Decimal (BCD) method of counting was devised. In this system four binary digits are used to represent each decimal digit. To illustrate this procedure, the number 105, is con
6、verted to a BCD number. In binary numbers, 10510=1,000,1012.,3.2.3 Octal Number System,The octal (base 8) number system is used to process large numbers by digital circuits. The octal system of numbers uses the same basic principles as the decimal and binary systems. The octal number system has a ba
7、se of 8. The largest number used in a base 8 system is 7. The place values starting at the left of the octal point are the powers of eight: 80=1, 81=8, 82=64, 83=512, 84=4,096, and so on.,3.2.4 Hexadecimal Number System,The hexadecimal number system is used in digital systems to process large number
8、 values. The base of this system is 16, which means that the largest number used in a place is 15. Digits used by this system are the numbers 0-9 and the letters A-F. The letters A-F are used to denote the digits 10-15, respectively. The place values to the left of the hexadecimal point are the powe
9、rs of 16160=1, 161=16, 162=256, 163=4,096, 164=65,536, and so on.,3.3 Binary Logic Circuits,Fig.3-1 Logic-gate symbols,3.3 Binary Logic Circuits,Fig.3-2 Quad-AND chip,3.4 Combination Logic Gates,Fig.3-3 The basic combination logic-gate symbols,3.4 Combination Logic Gates,表格,3.4 Combination Logic Gat
10、es,Fig.3-4 Logic circuit to accomplish Boolean equation ABC+ C=X,3.5 Timing and Storage Elements,3.5.1 Flip-Flops 3.5.2 Counters,3.5.1 Flip-Flops,1. R-S,Fig.3-5 The R-S flip-flop logic construction,3.5.1 Flip-Flops,3-6.TIF,3.5.1 Flip-Flops,表格,3.5.1 Flip-Flops,Fig.3-7 The R-S-T flip-flop logic constr
11、uction,3.5.1 Flip-Flops,3-8.TIF,3.5.1 Flip-Flops,表格,3.5.1 Flip-Flops,2. J-K,Fig.3-9 The clock signal,3.5.1 Flip-Flops,Fig.3-10 Logic symbols for edge triggered flip-flops a) Leading edge triggering b) Trailing edge triggering,3.5.1 Flip-Flops,3-11.TIF,3.5.1 Flip-Flops,表格,3.5.2 Counters,1. digital 2.
12、 numerical 3. filp-flop 4. decimal 5. radix 6. with 7. power 8. weighted 9. binary 10. manipulate 11. subscript 12. remainder,3.5.2 Counters,13. quotient 14. octal 15. hexadecimal 16. circuitry 17. bistable 18. relay 19. capacity 20. buffer 21. simultaneously 22. algebra 23. truth 24. variable,3.5.2 Counters,25. alphabet 26. complement 27. multivibrator 28. trigger 29. symmetrical 30. leading 31.trailing 32. counter,
