精品国产99久久久久久www_亚洲精彩视频在线观看的_性欧美婬妇ⅹxxx视频_里番肉工口全彩老师_a天堂最新在线观看_精品国产在天天在线观看_免费看那种视频_樱桃电视剧全集播放_成人性视频免费看的鲁片_中国伦理影院

Dual Decade Counters

This circuit contains eight master-slave flip-flops and additional gating to implement two individual four-bit counters. The HD74LS390 incorporates dual divide-by-two and divide-by-five counters, which can be used to implement cycle lengths equal to any whole and / or cumulative multiples of 2 and / or 5 up to divide-by-100. When connected as a biquinary counter, the separate divide-by-two circuit can be usedto provide symmetry (a square wave) at the final output stage.