占空比可调的方波发生器.doc

目录

一、课程设计目的 ····································································································· 2

二、课程设计正文 ····································································································· 2

2.1 总体论述······································································································· 2

2.2 方案选型······································································································· 2

2.2.1 总体方案······························································································· 2

2.2.2 各单元电路方案及集成电路 ······································································ 2

2.3 电路原理图···································································································· 4

2.4 运行详细描述································································································· 8

2.5 制作调试过程································································································· 9

2.6 器件清单······································································································ 14

三、实验设计总结或结论¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼..........................................................15

四、参考文献 ..¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼¼.............15

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一、 课程设计目的

1、 掌握电子系统的一般设计方法。

2、 理解占空比可调的方波发生器的设计原理，掌握占空比的设计原理和计算。

3、 提高综合应用所学只是来指导实践的能力。

二、 课程设计正文

2.1 总体论述

2.1.1 设计任务

1、根据技术要求和现有开发环境，分析课设题目；

2、设计系统实现方案；

3、设计绘制电路原理图并选择元器件；

4、焊接电路、调试；

5、记录结果、修改并完善设计；

6、编写课程设计报告。

2.1.2、技术要求

（1） 设计要求： 设计一方波产生电路。 输出要求： 占空比可调； 输出方波电压值： 8v<|V0|<15v;
振荡周期：2ms<T<10ms。

（2）设计方法：使用集成运算放大器 555 定时器、稳压二极管、二极管、电阻等器件。

2.2 方案选型

2.2.1 总体方案

直流电源


电压控制


555 置
位


555 充
电


555 复
位


555 放
电

图（1） 总体方案

2.2.2 各单元电路方案及集成电路

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方案一

图（2）555 定时器内部结构

图（3） 555 定时器的输出波形

接通 VCC 后瞬间，VCC 通过 R 对 C 充电，当 uc 上升到 2VCC/3 时，将触发器置 0，uo＝0，放
电管 T 导通，C 通过 T 放电，电路进入稳态。

uI 到来时，因为 uI＜VCC/3，使 uO 又由 0 变为 1，电路进入暂稳态。放电管 T 截止，VCC

经 R 对 C 充电。直到 uC 上升到 2VCC/3 时，uO＝0，T 导通，C 放电，电路恢复到稳定状态。
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