74LS系列芯片的比较全的简介,74系列虽然已不是主流,但在一些硬件电路中还是时常见到,其低价格高性能的特点，仍然是电子电路应用中不可缺少的一员.-74LS series chips Compare the profiles, although the 74 Series is not the mainstream, but in some hardware circuit or often see that its high-performance low-cost feature is th