Integrated Circuits Used 74LS00 74LS20 Procedure Add IC 74LS00 into ICBase-2 (74LS00).Add IC 74LS20 into ICBase-3 (74LS20).Connect Input-0 to Pin-1 (Input) of ICBase-2 (74LS00).Connect Input-1 to Pin-2 (Input) of ICBase-2 (74LS00).