课程设计数字电子秤的设计.doc

~~ 1 1 实验目的、意义………………………………………………………………… 1 2 模块电路设计及比较………………………………………………………… 2 电源模块…………………………………………………………………… 2 电源原理…………………………………………………………………… 2 . 2 电源电路图……………………………………………………………… 3 、放大及零位调整模块…………………………………………… 3 称重传感器……………………………………………………………… 3 压敏电阻………………………………………………………………… 4 放大、零位调整电路……………………………………………… 5 A/D 转换模块……………………………………………………… 7 ………………………………………………………………… 9 LED 显示器结构及分类……………………………………………… 9 LED 显示器分类…………………………………………………………… 10 LE D显示器的参数…………………………………………………………… 11 3电子秤的设计考虑……………………………………………………… 11 比率式测量方式…………………………………………………………………… 11 PCB 布线………………………………………………………………… 12 4系统测试……………………………………………………………………………… 12 5本文小结…………………………………………………………………… 12 附录 A ……………………………………………………………………… 13 附录 B ……………………………………………………………………… 13 附录 C ………………………………………………………………………… 14 参考文献………………………………………………………………………… 14 致谢………………………………………………………………………………………… 15 ~~ 2 数字电子秤的设计摘要本设计分五个模块:电源模块、数据采集及放大模块、模数( A/D )转换模块、自动换档模块、显示模块。本电路应用压敏电阻构成秤重电桥来采集电压的微小变化,经过放大电路放大后送入 A/D 7107 ,对输入电压信号进行转换成数字量输出;显示模块直接连接数码管构成,显示实际测量值。同时根据输出,自动判断出所加压力的大小来改变量程,实现自动换挡。外部电路非常简单,方便制作。关键字: 模数( A/D)转换秤重电桥压敏电阻自动换档 The design that the numerical electronics calls Abstruct This design divides five mold pieces:The power supply mold piece, data collects and enlarges a mold piece, mold several and shift gear a mold piece, the manifestation mold piece electric circuit application presses quick electric posing steelyard heavy electricity bridge to collect the small variety of electric voltage, has been enlarged electric circuit to send into A/D a conversion the 7107 after enlarging, to importation the electric voltage signal carry ona conversion numerical quantity exportation;Show a mold piece a direct conjunction figures tube to constitute, show actual measured the meantime according to exportation, judge the size of pressure that add automatically to change a quantity distance, the realization changes to block exterior