Integrated Circuits Used 74LS151 Procedure Connect Pin-20 (VCC) of ICBase-1 (74LS151) to Pin-15 (Input) of ICBase-1 (74LS151).Connect Pin-17 (Input) of ICBase-1 (74LS151) to Pin-16 (Input) of ICBase-1 (74LS151).Add IC 74LS151 into ICBase-1 (74LS151).