图书管理系统，采用人机对话的操作方式，界面设计美观友好、操作灵活、方便、快捷、准确、数据存储安全可靠。-Library management system, man-machine dialogue mode of operation, beautiful and friendly interface design, flexible operation, convenient, fast, accurate, safe and reliable data storage.

A/D D/A转换 单片机at89c51 adc0808 dac0832 包含显示模块 报警模块-A/D D/A converter microcontroller at89c51 adc0808 dac0832 Alarm module contains the display module