补充问题： 测试后流水灯正常 但是数码管显示不正常 第三位一直显示5 前两位隐隐约约看到非常暗的数字 调整电位器 数码管无任何现象-Supplementary question: after testing the normal lights flow but abnormal digital display shows 5 third place has been very dark to see the two vague figures to adjust the digital potentiometer control without any phenomenon