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Chapter8 Generation and Shaping of Pulse Signal
本章导读
555定时器是一种多用途的数字-模拟混合集成电路,利用它能极方便地构成施密特触发器、单稳态触发器和多谐振荡器。
主要应用领域包括:
波形的产生和变换、测量与控制、家用电器、电子玩具等。
555定时器的8个管脚的作用分别为:
管脚1 GND(地),接地,作为低电平(0V)
管脚2 TRIG(触发),当此引脚电压大于1/3 VCC时,输出端为高电平。
管脚3 OUT(输出) 输出高电平或低电平。
管脚4 RST(复位) 当此引脚接高电平时定时器工作,当此引脚接地时芯片复位,输出低电平。
管脚5 CTRL(控制) 控制芯片的阈值电压。(当此管脚接空时默认两阈值电压为1/3 VCC与2/3 VCC).
管脚6 THR(阈值threshold) 当此引脚电压大于2/3 VCC时输出端为低电平。
管脚7 DIS(放电discharge) 内接OC门,用于给电容放电。
管脚8 VCC(供电) 提供高电平并给芯片供电。
本章要点
8-1 555定时器的电路结构和工作原理
8-2 555定时器构成的施密特触发器
8-3 555定时器构成的单稳态触发器
8-4 555定时器构成的多谐振荡器
8-5 555定时器的应用电路
图1 555定时器所构成的施密特触发器仿真电路
图2 555定时器所构成的施密特触发器仿真结果
-1.1 Structure and Methods
-1.2 Introductory
-Chapter1 Introductory Concepts
-Test1
-2.1 Number Systems
-2.2 Codes
-Chapter2 Number systems and Codes
-Test2
-3.1 Logic Gates(1)
-3.2 Logic Gates(2)
-Test3
-4.1 Boolean Algebra
-4.2 Logic Simplification
-Chapter4 Boolean Algebra and Logic Simplification
-Test4
-5.1 Analysis of combination logic circuit
--5-1 Analysis of combination logic circuit
-5.2 Design of combination logic circuit
--5-2 Design of combination logic circuit
-5.3 Half and Full Adders
-5.4 Encoders
-5.5.1 Decoders(1)
-5.5.2 Decoders(2)
-5.5.3 Decoders(3)
-5.5.4 Decoders(4)
-5.6.1 Multiplexers (Data Selectors)(1)
--5-6 Multiplexers (Data Selectors)(1)
-5.6.2 Multiplexers (Data Selectors)(2)
--5-6 Multiplexers (Data Selectors)(2)
-5.7 Comparators
-Chapter5 Combinational Logic Circuit
-Test5
-6.1 Latches
-6.2 Flip-Flops
-6.3 Flip-Flops Applications
-Test6
-7.1 Analysis of Sequential logic circuit-1
--7–1 Analysis of Sequential logic circuit-1
-7.2 Analysis of Sequential logic circuit-2
--7–2 Analysis of Sequential logic circuit-2
-7.3 Design of Sequential logic circuit-1
--7.3 Design of Sequential logic circuit-1
-7.4 Design of Sequential logic circuit-2
--7-4 Design of Sequential logic circuit-2
-7.5 Counters-1
-7.6 Counters-2
-7.7 Registers-1
-7.8 Registers-2
-Chapter7 Sequential Logic Circuit
-Test7
-8.1 555 Timer circuit structure and working principle
--8.1 555 Timer circuit structure and working principle
-8.2 Application circuit of 555 Timer
--8.2 Application circuit of 555 Timer
-Chapter8 Generation and Shaping of Pulse Signal
-Test8