Integrated Circuits Used 74LS05 74LS02 Procedure Add IC 74LS05 into ICBase-2 (74LS05).Add IC 74LS02 into ICBase-3 (74LS02).Connect Pin-3 (Input) of ICBase-3 (74LS02) to Pin-18 (Output) of ICBase-2 (74LS05).Connect Input-1 to Pin-3 (Input) of ICBase-3 (74LS02).