第二节 555定时器及其应用

,第二节 555集成定时器及其应用,*,第二节 555定时器及其应用,555定时器的电路结构与功能,由555电路组成的单稳态触发器,由555电路组成的多谐振荡器,由555电路组成的施密特触发器,下页,总目录,推出,1,下页,返回,一、555定时器的电路结构与功能,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,。,应用领域：,波形的产生和变换、测量与控制、家用电器、电子玩具等。,555定时器产品型号繁多，但所有双极型产品型号最后的3位数码都是555，所有CMOS产品型号最后的4位数码都是7555。它们的功能和外部引脚的排列完全相同。,以下介绍国产,双极型定时器CB555,的电路结构和功能。,上页,2,返回,高电平触发端,电压控制端,低电平触发端,放电端,接地端,复位端,电源端,输出端,CB555由比较器C,1,和C,2,、基本,RS,触发器和集电极开路的放电三极管T三部分组成。,下页,上页,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,5,6,2,7,1,+,-,C,1,+,-,C,2,v,I1,TH,v,I2,TR,v,OD,DISC,V,CO,G,1,G,3,G,4,V,CC,R,D,v,C2,v,C1,V,R2,V,R1,3,下页,返回,上页,0,1,低 导通,低 导通,不变 不变,高 截止,高 截止,1,1,1,C,1,输出 0，C,2,输出 1,C,1,输出 1，C,2,输出 1,C,1,输出 1，C,2,输出 0,C,1,输出 0，C,2,输出 0,T,状态,v,O,v,I2,v,I1,R,D,输 出,输 入,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,5,6,2,7,1,+,-,C,1,+,-,C,2,v,I1,TH,v,I2,TR,v,OD,DISC,V,CO,G,1,G,3,G,4,V,CC,R,D,v,C2,v,C1,V,R2,V,R1,4,下页,返回,上页,二、用555定时器接成的施密特触发器,1. 电路结构,将555定时器的两个输入端连在一起作为信号输入端，即可得到施密特触发器。,滤波电容，为提高,V,R1,和,V,R2,的稳定性,信号输入端,5,6,2,7,v,I1,v,I2,V,R2,V,R1,0.01,F,v,I,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,V,R1,5,下页,返回,上页,2. 工作原理,v,O,O,t,v,I,O,t,v,o,由高电平变为低电平和由低电平变为,高,电平,所对应的,v,I,值不同，就形成了施密特触发特性。,5,6,2,7,v,I1,v,I2,V,R2,V,R1,0.01,F,v,I,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,6,下页,返回,上页,v,I,O,t,v,O,O,t,U,T+,U,T-,U,T,如果参考电压由外接电压,V,CO,供给，,U,T+,=,V,CO,U,T-,= 1/2,V,CO,U,T,= 1/2,V,CO,。,电压传输特性,回差电压,仿真,7,下页,返回,上页,三、用,555,定时器接成的单稳态触发器,1.电路结构,触发信号的输入端,没有触发信号时,v,I,处于高电平，稳态时,v,c1,=,v,c2,=1,、,Q,=0，,v,o,=0,。,v,I,v,C,0.01,F,C,R,5,6,2,7,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,8,下页,返回,上页,2,/,3,V,CC,t,w,v,C,O,t,v,I,O,t,v,O,O,t,2.工作原理,通常,t,w,的范围为几微秒到几分钟。但随着,t,w,的宽度增加它的精度和稳定度也将下降。,v,I,v,C,0.01,F,C,R,5,6,2,7,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,9,下页,返回,上页,触发脉冲的宽度要小于,t,w,触发负脉冲应在,v,C,上升到,2,/,3,V,CC,之前回到高电平。,2,/,3,V,CC,t,w,v,C,O,t,v,I,O,t,v,O,O,t,v,I,v,C,0.01,F,C,R,5,6,2,7,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,仿真,10,v,I,v,C,0.01,F,C,R,5,6,2,7,v,O,5,k,5,k,5,k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,下页,返回,上页,应用举例,动画,11,下页,返回,上页,四、用555定时器接成的多谐振荡器,v,O,O,t,v,C,O,t,t,p2,t,p1,充电回路：,V,CC,R,1,R,2,C,地。,放电回路：,C,R,2,T ,地。,v,C,0.01,F,C,R,1,5,6,2,7,v,O,5k,5k,5k,T,D,G,2,Q,Q,8,4,3,1,+,-,C,1,+,-,C,2,G,1,G,3,G,4,V,CC,v,C2,v,C1,R,2,12,下页,返回,上页,v,O,O,t,v,C,O,t,t,p1,t,p2,振荡周期和振荡频率,振荡周期,振荡频率,占空比,用CB555定时器组成的振荡器，最高工作频率可达,500kHz,。,13,下页,返回,上页,占空比可调的多谐振荡器,R,1,R,2,充电回路：,V,CC,R,1,D,1,C,地。,放电回路：,C,D,2,R,2,T ,地。,占空比,8 4,7,2,1 5,6,3,555,R,2,R,1,R,P,D,2,D,1,C,0.01,F,v,O,V,CC,仿真,14,上页,返回,应用举例,()、()均为多谐振荡电路，,当,v,o1,输出高电平时() 振荡，,v,o2,输出矩形脉冲，,当,v,o1,输出低电平时() 被置0，,v,o2,输出低电平。,8 4,7,2,1 5,6,3,555,R,12,R,11,C,1,0.01,F,v,O1,V,CC,8 4,7,2,1 5,6,3,555,R,22,R,21,C,2,0.01,F,v,O2,(),(),仿真,15,MaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E2B+y(u%r#oWlThQeNbJ8G5D1A-x*t$qYnVkSgPdMaI7F3C0z)v&s!pXmUiRfOcK9H6E2B+x(u%rZoWlThQeMbJ8G4D1A-w*t!qYnVjSgPdLaI6F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u$rZoWkThQeMbJ7G4D1z-w*t!qYmVjSgOdLaI6F3B0y)v%s#pXlUiQfNcK8H5E2A+x*u$rZnWkThPeMaJ7G4C1z-w&t!qYmVjRgOdL9I6F3B0y(v%s#oXlUiQfNbK8H5D2A+x*u$qZnWkShPeMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQfNbK8G5D2A-x*u$qZnVkShPdMaJ7F4C0z)w&s!pYmUjRfOcL9H6E3B+y(u%r#oWlTiQeNbJ8G5D1A-x*t$qYnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcK9H6E2B+y(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u$rZoWkThQeMbJ8G4D1z-w*t!qYnVjSgOdLaI6F3C0y)v%s#pXlUiRfNcK8H5E2A+x(u$rZnWkThPeMbJ7G4C1z-w&t!qYmVjRgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkShPeMaJ7G4C1z)w&t!pYmVjRgOcL9I6E3B0y(v%r#oXlTiQfNbK8G5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&s!pYmUjRgOcL9H6E3B+y(v%r#oWlTiQeNbK8G5D1A-x*t$qZnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcK9H6E2B+y(u%r#oWlThQeNbJ8G5D1A-w*t$qYnVkSgPdLaI7F3C0z)v&s#pXmUiRfOcK9H5E2B+x(u%rZoWkThQeMbJ8G4D1z-w*t!qYnVjSgPdLaI6F3C0y)v&s#pXlUiRfNcK9H5E2A+x(u$rZoWkThPeMbJ7G4D1z-w&t!qYmVjSgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkThPeMaJ7G4C1z-w&t!pYmVjRgOdL9I6E3B0y(v%s#oXlTiQfNbK8H5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&s!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZRgOdL9I6E3B0y(v%s#oXlTiQfNbK8H5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E2B+y(u%r#oWlTiQeNbJ8G5D1A-x*t$qYnVkSgPdMaI7F3C0z)v&s!pXmUiRfOcK9H6E2B+x(u%rZoWlThQeMbJ8G4D1A-w*t!qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u$rZoWkThQeMbJ7G4D1z-w*t!qYmVjSgOdLaI6F3B0y)v%s#pXlUiQfNcK8H5E2A+x*u$rZnWkThPeMbJ7G4C1z-w&t!qYmVjRgOdL9I6F3B0y(v%s#oXlUiQfNbK8H5D2A+x*u$qZnWkShPeMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B0y(v%r#oXlTiQfNbK8G5D2A-x*u$qZnVkShPdMaJ7F4C0z)w&s!pYmUjRfOcL9H6E3B+y(u%r#oWlTiQeNbJ8G5D1A-x*t$qZnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcK9H6E2B+y(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u%rZoWkThQeMbJ8G4D1z-w*t!qYnVjSgOdLaI6F3C0y)v%s#pXlUiRfNcK8H5E2A+x(u$rZnWkThPeMbJ7G4C1z-w&t!qYmVjSgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkShPeMaJ7G4C1z)w&t!pYmVjRgOcL9I6E3B0y(v%r#oXhPeMbJ7G4D1z-w&t!qYmVjSgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkShPeMaJ7G4C1z)w&t!pYmVjRgOcL9I6E3B0y(v%s#oXlTiQfNbK8H5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&s!pYmUjRgOcL9H6E3B+y(v%r#oWlTiQeNbK8G5D1A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E2B+y(u%r#oWlThQeNbJ8G5D1A-w*t$qYnVkSgPdLaI7F3C0z)v&s#pXmUiRfOcK9H5E2B+x(u%rZoWlThQeMbJ8G4D1A-w*t!qYnVjSgPdLaI6F3C0y)v&s#pXlUiRfNcK9H5E2A+x(u$rZoWkThPeMbJ7G4D1z-w&t!qYmVjSgOdLaI6F3B0y)v%s#pXlUiQfNcK8H5E2A+x*u$rZnWkThPeMaJ7G4C1z-w&t!pYmVjRgOdL9I6E3B0y(v%s#oXlTiQfNbK8H5D2A-x*u$qZnWkShPeMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E3B+y(qZnWkShPeMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZnVkShPdMaI7F4C0z)w&s!pYmUjRfOcL9H6E3B+y(u%r#oWlTiQeNbJ8G5D1A-x*t$qYnVkSgPdMaI7F3C0z)v&s!pXmUiRfOcK9H6E2B+x(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u$rZoWkThQeMbJ7G4D1z-w*t!qYmVjSgOdLaI6F3C0y)v%s#pXlUiRfNcK8H5E2A+x(u$rZnWkThPeMbJ7G4C1z-w&t!qYmVjRgOdL9I6F3B0y(v%s#oXlUiQfNbK8H5D2A+x*u$qZnWkShPeMaJ7G4C1z)w&t!pYmVjRgOcL9I6E3B0y(v%r#oXlTiQfNbK8G5D2A-x*u$qZnVkShPdMaJ7F4C0z)w&s!pYmUjRfOcL9H6E3B+y(v%r#oWlTiQeNbK8G5D1A-x*t$qZnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcK9H6E2B+y(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVkSgPdLaI7F3C0z)v&s#pXmUiRfOcK9H5E2B+x(u%rZoWkThQeMbJ8G4D1z-w*t!qYnVjSK9H6E2B+y(u%rZoWlThQeNbJ8G5D1A-w*t$qYnVkSgPdLaI7F3C0z)v&s#pXmUiRfOcK9H5E2B+x(u%rZoWkThQeMbJ8G4D1z-w*t!qYnVjSgOdLaI6F3C0y)v&s#pXlUiRfNcK9H5E2A+x(u$rZoWkThPeMbJ7G4D1z-w&t!qYmVjSgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkShPeMaJ7G4C1z-w&t!pYmVjRgOdL9I6E3B0y(v%s#oXlTiQfNbK8H5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&s!pYmUjRgOcL9H6E3B+y(v%r#oXlTiQeNbK8G5D2A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E2B+y(u%r#oWlThQeNbJ8G5D1A-w*t$qYnVkSgPdMaI7F3C0z)v&s!pXmUiRfOcK9H6E2B+x(u%rZoWlThQeMbJ8G4D1A-w*t!qYnVjSgPdLaI6F3C0y)v&s#pXlUiRfNcK9H5E2A+x(u$rZoWkThQeMbJ7G4D1v&s!pXmUiRfOcK9H6E2B+x(u%rZoWlThQeMbJ8G4D1A-w*t!qYnVjSgPdLaI6F3C0y)v&s#pXmUiRfNcK9H5E2B+x(u$rZoWkThQeMbJ7G4D1z-w*t!qYmVjSgOdLaI6F3B0y)v%s#pXlUiQfNcK8H5E2A+x*u$rZnWkThPeMaJ7G4C1z-w&t!qYmVjRgOdL9I6F3B0y(v%s#oXlUiQfNbK8H5D2A+x*u$qZnWkShPeMaJ7F4C1z)w&t!pYmUjRgOcL9I6E3B+y(v%r#oXlTiQfNbK8G5D2A-x*u$qZnVkShPdMaJ7F4C0z)w&s!pYmUjRfOcL9H6E3B+y(u%r#oWlTiQeNbJ8G5D1A-x*t$qYnVkSgPdMaI7F3C0z)v&s!pXmUjRfOcK9H6E2B+y(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfNcK9HA-x*t$qZnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcK9H6E2B+y(u%rZoWlThQeNbJ8G4D1A-w*t$qYnVjSgPdLaI7F3C0y)v&s#pXmUiRfOcK9H5E2B+x(u%rZoWkThQeMbJ8G4D1z-w*t!qYnVjSgOdLaI6F3C0y)v%s#pXlUiRfNcK8H5E2A+x(u$rZnWkThPeMbJ7G4C1z-w&t!qYmVjSgOdL9I6F3B0y)v%s#oXlUiQfNcK8H5D2A+x*u$rZnWkShPeMaJ7G4C1z)w&t!pYmVjRgOcL9I6E3B0y(v%r#oXlTiQfNbK8H5D2A-x*u$qZnWkShPdMaJ7F4C1z)w&s!pYmUjRgOcL9H6E3B+y(v%r#oWlTiQeNbK8G5D1A-x*t$qZnVkSgPdMaI7F4C0z)v&s!pXmUjRfOcL9H6E2B+y(u%r#oWlPdMaJ7F4C1z)w&s!pYmUjRgOcL9H6E3B+y(v%r#oWlTiQeNbK8G5D1A-x*t$qZnVkShPdMaI7F4C0z)w&s!pXmUjRfOcL9H6E2B+y(u%r#oWlThQeNbJ8G5D1A-w*t$qYnVkSgPd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