三位二进制加1与加2计数器 ：三位二进制模5计数器。当外部输入X = 1时，计数器加2计数；外部输入X = 0时，计数器加1计数。“模5”为逢“5”进1计数。

原始条件：使用D触发器( 74 LS 74 )、“与”门 ( 74 LS 08 )、“或”门( 74 LS 32 )、非门 ( 74 LS 04 )，设计三位二进制模5计数器。

-The three binary counter plus 1 and plus 2 : three binary mod 5 counter. X = 1 when the external input, the counter plus 2 counts　external input X = 0, the counter by 1 count. " Die 5"　for every " 5"　into a count. Original conditions: Use D flip-flop (74 LS 74), " and"　gate (74 LS 08), " or"　gate (74 LS 32), non-gate (74 LS 04), three binary mod 5 counter design.