555计算器 是软件编程人员针对555芯片定制的软件，用户输入自己想要的频率值，然后软件能计算出来555对应引脚上的电阻与电容值，非常方便。-555 calculator is a software programmer for the 555 chip custom software, users enter their desired frequency value, then the software calculated the resistance and capacitance values ​ ​ 555 corresponding pin is very convenient.