Also note that "'''Step Size'''" is different from "'''Step Ceiling'''". Step size specifies how large each time step of the simulation is when using the "Simulation Stepping" feature. Step Size does not factor into the simulation when running the engine in "'''Walk'''" or "'''Run'''" modes, where the simulation engine itself decides how large a step to take. On the other hand, Step Ceiling is the maximum value that you specify for the automatically calculated time step when a simulation is "Walked" or "Run".
To set the step size, go to '''Simulate Menu''' and select the "'''Time Options...'''" to open the Simulation Time Options Dialog. Or click the button labeled {{key|...}} on the '''[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|[[Main toolbar|Main Toolbar]]]]]]]]]]]]]]]]]]]]]]]]]]''' on the left of the Run button as shown in the figure below. You can also use the keyboard shortcut "Ctrl+I" to open this dialog, which is shown below:
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[[File:DigiTUT1_3.png|thumb|550px|State of the digital circuit at t = 20nswith In1 = In2 = In3 = 0.]]
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[[File:DigiTUT1_4.png|thumb|550px|State of the digital circuit at t = 40nswith In1 = 1 and In2 = In3 = 0.]]
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[[File:DigiTUT1_5.png|thumb|550px|State of the digital circuit at t = 60nswith In1 = In2 = In3 = 1.]]
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