文档介绍：第四章门和电路
Gates and Circuits
Chapter Goals
Identify the basic gates and describe the behavior of each
识别基础的门电路,描述每种门的行为
Describe how gates are implemented using transistors
bine basic gates into circuits
用基础门合成电路
Describe the behavior of a gate or circuit using Boolean expressions, truth tables, and logic diagrams
利用门电路、真值表和逻辑框图描述门或电路的行为
Chapter Goals
Compare and contrast a half adder and a full adder
比较半加器和全加器之间的异同点
Describe how a multiplexer works
描述多路复用器是如何运作的
Explain how an S-R latch operates
解释如何操作S-R锁存器
Describe the characteristics of the four generations of integrated circuits
描述四代集成电路的特性
Computers and Electricity
Gate A device that performs a basic operation on electrical signals
对电信号执行基础运算的设备,接受一个或多个输入信号,生成一个输出信号。
Circuits bined to perform plicated tasks
相互关联的门的组合,用于实现特定的逻辑函数。
Computers and Electricity
There are three different, but equally powerful, notational methods for describing the behavior of gates and circuits
Boolean expressions布尔表达式
logic diagrams逻辑框图
truth tables真值表
Computers and Electricity
Boolean expressions Expressions in Boolean algebra, a mathematical notation for expressing two-valued logic
This algebraic notation are an elegant and powerful way to demonstrate the activity of electrical circuits
表示二值逻辑的一种数学表达式,能够表示电路的行为。
Boolean Algebra
A • B 与运算
A+B 或运算
A 非运算
A⊕B 异或运算
零律 A+0=A
A•0=0
幺律 A+1=1
A•1=A
幂等律 A+A=A
A•A=A
求补律 A+A =1
A•A =0
Boolean Algebra
交换律:A+B=B+A A •B=B •A
结合律:A+(B+C)=(A+B)+C
A •(B •C)=(A •B) •C
分配律:A •(B+C)=A •B+A •C
A+B •C==(A+B) •(A+C)
狄摩根定律:A+B=A •B A •B=A+B
Computers and Electricity
Logic diagram A graphical representation of a circuit
Each type of gate is represented by a specific graphical symbol
表示电路一种图示方法
Truth table A table showing all possible input value and the associated output values
表示可能的输入和可能输出的一种表格。
Gates
Let’s examine the processing of the following six types of gates
NOT 非
AND 与
OR 或
XOR 异或
NAND 与非
NOR 与或
Typically, logic diagrams are black and white, and the gates are disti