Select the signal Z and click on the 1 near the alphabet keys to set Z to 1 for the next simulation steps. Close the stimulus window and click the step button twice to run the simulation for another 80ns. You'll now see the complete output waveform of the circuit. You have now tried all possible combinations for the inputs of this circuit. The comb buttons in the simulation windows allow you to shrink and expand the time scale of the simulation.
Schematic Changes Close the simulator.
Invoke the Schematic Editor or go back to it if you already have it running. You will be modifying your circuit by adding AND, OR, and NOT gates to the circuit so that is it logically equivalent to Figure 3-7 from the text. As mentioned earlier, there are toolbars across the left side and the top of the window. Now click on the toolbar button with the AND gate icon. A device library window will pop up.