文档介绍：of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of t
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图8-3 MCU与4连排8段数码管的连接
〔三〕基本原理
8段数码管一般由8个发光二极管〔Llight-emitting diode，LED〕组成，每一个位段就是一个发光二极管。一个8段数码管分别由a、b、c、d、e、f、g位段，外加上一个小数点的位段h〔或记为dp〕组成。根据公共端所接电平的高低，可分为共阳极和共阴极两种。有时数码管不需要小数点，只有7个位段，称7段数码管。共阴极8段数码管的信号端高电平有效，只要在各个位段上加上相应的信号即可使相应的位段发光，比方：要使a段发光，则在a段加上高电平即可。共阳极的8段数码管则相反，在相应的位段加上低电平即可使该位段发光。
四．编程
〔一〕流程图
of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of the scope of protection, complete with warning signs, isolating network protection facilities
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of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of the scope of protection, complete with warning signs, isolating network protection