`
oywl2008
  • 浏览: 1050671 次
  • 性别: Icon_minigender_1
  • 来自: 广州
社区版块
存档分类
最新评论

logic gate (AND, OR, XOR, NOT, NAND, NOR and XNOR)

 
阅读更多

A logic gate is an elementary building block of a digital circuit. Most logic gates have two inputs and one output. At any given moment, every terminal is in one of the two binaryconditions low (0) or high (1), represented by different voltage levels. The logic state of a terminal can, and generally does, change often, as the circuit processes data. In most logic gates, the low state is approximately zero volts (0 V), while the high state is approximately five volts positive (+5 V).

There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.

The AND gate is so named because, if 0 is called "false" and 1 is called "true," the gate acts in the same way as the logical "and" operator. The following illustration and table show the circuit symbol and logic combinations for an AND gate. (In the symbol, the input terminals are at left and the output terminal is at right.) The output is "true" when both inputs are "true." Otherwise, the output is "false."

/WhatIs/images/and.gif (220 bytes)

AND gate

Input 1 Input 2 Output
     
  1  
1    
1 1 1

The OR gate gets its name from the fact that it behaves after the fashion of the logical inclusive "or." The output is "true" if either or both of the inputs are "true." If both inputs are "false," then the output is "false."

/WhatIs/images/or.gif (224 bytes)

OR gate


Input 1 Input 2 Output
     
  1 1
1   1
1 1 1

 

The XOR ( exclusive-OR ) gate acts in the same way as the logical "either/or." The output is "true" if either, but not both, of the inputs are "true." The output is "false" if both inputs are "false" or if both inputs are "true." Another way of looking at this circuit is to observe that the output is 1 if the inputs are different, but 0 if the inputs are the same.

 

XOR gate

Input 1 Input 2 Output
     
  1 1
1   1
1 1  

 

A logical inverter , sometimes called a NOT gate to differentiate it from other types of electronic inverter devices, has only one input. It reverses the logic state.

 

/WhatIs/images/not.gif (240 bytes)

 

Inverter or NOT gate
Input Output
1  
  1

 

The NAND gate operates as an AND gate followed by a NOT gate. It acts in the manner of the logical operation "and" followed by negation. The output is "false" if both inputs are "true." Otherwise, the output is "true."

/WhatIs/images/nand.gif (240 bytes)

NAND gate

Input 1 Input 2 Output
    1
  1 1
1   1
1 1  

 

The NOR gate is a combination OR gate followed by an inverter. Its output is "true" if both inputs are "false." Otherwise, the output is "false."

/WhatIs/images/nor.gif (237 bytes)

NOR gate

Input 1 Input 2 Output
    1
  1  
1    
1 1  

 

The XNOR (exclusive-NOR) gate is a combination XOR gate followed by an inverter. Its output is "true" if the inputs are the same, and"false" if the inputs are different.

/WhatIs/images/xnor.gif (278 bytes)

XNOR gate

Input 1 Input 2 Output
    1
  1  
1    
1 1 1

Using combinations of logic gates, complex operations can be performed. In theory, there is no limit to the number of gates that can be arrayed together in a single device. But in practice, there is a limit to the number of gates that can be packed into a given physical space. Arrays of logic gates are found in digital integrated circuits (ICs). As IC technology advances, the required physical volume for each individual logic gate decreases and digital devices of the same or smaller size become capable of performing ever-more-complicated operations at ever-increasing speeds.

See an introductory tutorial on logic gates:

 

 

http://whatis.techtarget.com/definition/logic-gate-AND-OR-XOR-NOT-NAND-NOR-and-XNOR

 

 

分享到:
评论

相关推荐

    Electro-Optic Directed XNOR Logic Gate Based on U-Shaped Waveguides and Microring Resonators

    此外,文章在介绍部分还回顾了光学计算领域的研究进展,指出研究者们已经报告了基于定向逻辑概念的各种逻辑电路,包括加法器、OR/NOR门、AND/NAND门和编码器等。关于XOR和XNOR运算的实现,之前的研究通过级联马赫-曾...

    GH命令英文详解.pdf

    在 Logic 部分,GH 命令英文详解.pdf 介绍了逻辑运算符,包括 Boolean、Gate And、Gate And Ternary、Gate Majority、Gate Nand、Gate Nor、Gate Not、Gate Or、Gate Or Ternary、Gate Xnor、Gate Xor 等逻辑运算符...

    Logic Gate Simulator-开源

    该模拟器的核心特性是其直观的拖放界面,用户可以通过简单的操作在屏幕上布置和连接各种逻辑门,如AND、OR、NOT、NAND、NOR、XOR和XNOR等。这种互动方式使抽象的电路设计变得可视化,有助于初学者直观理解逻辑运算的...

    Texas_Instruments_Logic_Gate.zip

    逻辑门是数字电路的基本单元,通过不同的输入组合产生特定的输出,如AND门、OR门、NOT门、NAND门、NOR门、XOR门和XNOR门等。这些门电路在计算机、通信设备、控制电路等各种电子系统中起到至关重要的作用。 TI逻辑门...

    Microprocessor Design Principles and Practices With VHDL

    This section covers the basic logic gates (AND, OR, NOT, NAND, NOR, XOR, XNOR) and how they are represented in circuit diagrams. **2.9 Example: Designing a Car Security System** An example ...

    数字设计原理与实践_第六章答案.doc

    2. Logic Gate:逻辑门是数字电路的基本组成部分,包括AND、OR、NOT、NAND、NOR、XOR 等多种类型的逻辑门。每种逻辑门都有其特定的逻辑功能和电路实现方法。 3. 74系列数字电路:74系列数字电路是指一系列通用的...

    数字电路英文版第五单元PPT学习教案.pptx

    接着,本单元还涵盖了与或逻辑(AND-OR Logic)及其变体,如与或非逻辑(AND-OR-Invert),以及互斥或(exclusive-OR, XOR)和互斥非或(exclusive-NOR, XNOR)门。这些门实际上是与或逻辑的一种形式,用于实现更...

    grasshopper运算器名称总结.pdf

    * Gate Nand: 非并集 * Gate Nor: 非或 * Gate Not: 非 * Gate Or: 或 * Gate Or Ternary: 三元或 * Gate Xnor: 异或 * Gate Xor: 亦或 List * Dispatch: 分配 * List Item: 列表项 * List Length: 列表长度 * ...

    Universal Linear-Optical Logic Gate with Maximal Intensity Contrast Ratios

    本研究旨在提出一种理论模型来获得线性光学逻辑门的最佳解决方案,并通过实验验证了所有常见逻辑门(如AND、OR、NOT、NAND、NOR、XOR、XNOR等)的功能实现。这些逻辑门基于超紧凑的等离子体波导结构制成,这使得它们...

    犀牛grasshopper运算器名称解释.doc

    * Gate Majority:Gate Nand:Gate Nor:Gate Not:Gate Or:Gate Or Ternary:Gate Xnor:Gate Xor: List相关知识点: * Dispatch:分配,用于描述列表中的数据分配。 * List Item:清单项,用于描述列表中的...

    EDA实验报告

    - **或门**(OR Gate):只要有任一输入为高电平,输出就为高电平。 - **非门**(NOT Gate 或 Inverter):输入电平反转,高变低,低变高。 - **与非门**(NAND Gate):与门的非操作,即所有输入都为高时,输出...

    应用数字技术设计教材

    数字电路设计的核心在于理解并运用各种逻辑门(如AND、OR、NOT、NAND、NOR、XOR、XNOR)的性质,以及它们之间的组合与转换,这将帮助你构建出满足特定功能的逻辑电路。 FPJA-CPLD是一种可编程逻辑器件,它具有很高...

    VHDL数字系统设计(课件).rar

    3. **逻辑操作与函数**:学习如何使用VHDL实现基本逻辑门(AND、OR、NOT、NAND、NOR、XOR、XNOR)以及更复杂的组合逻辑电路,例如半加器、全加器、比较器等。 4. **时序逻辑设计**:掌握寄存器(REGISTERS)、...

    数字电路与逻辑设计B PPT+习题解答

    2. **逻辑门电路**:基本逻辑门包括AND、OR、NOT、NAND、NOR、XOR和XNOR,它们是构建更复杂逻辑电路的基础。通过这些门电路的组合,可以实现任意布尔函数。理解其工作原理和真值表,是分析和设计数字电路的第一步。 ...

    grasshopper中文版运算器名称对照页.pdf

    逻辑运算器包括 **Boolean** 运算,如 **Gate And** (并集)、**Gate And Ternary** (三元并集)、**Gate Majority**、**Gate Nand**、**Gate Nor**、**Gate Not**、**Gate Or**、**Gate Or Ternary**、**Gate Xnor** ...

    可编程逻辑基础(硬件基础知识)()

    1. **逻辑门和布尔代数**:这是所有数字系统的基础,包括基本逻辑门(AND、OR、NOT、NAND、NOR、XOR、XNOR)以及布尔代数定律,如分配律、德摩根定律等。 2. **VHDL/Verilog**:这两种硬件描述语言是描述和设计FPGA...

    硬件电路基础知识 v0.3

    **1.1.1.1 与门AND Gate** 与门是最基本的逻辑门之一,它有多个输入但只有一个输出。当所有输入信号同时为高电平(通常表示为1)时,输出才为高电平;否则,输出为低电平(通常表示为0)。与门的逻辑功能可以用布尔...

    Microprocessor Design Vhdl.pdf

    Contents 1. Designing a Microprocessor......................................................................................................VHDL code for a 2-input NAND gate...............................

Global site tag (gtag.js) - Google Analytics