Instructions for
Logic Lab 1

This is a virtual lab project. It gives you control over the logic levels and waveforms that are applied to the input terminals of various combination logic circuits. It also gives you an oscillocope display of the logic level or waveform at any pin on the project's IC device. Your basic steps are:

• Select a circuit
• Select the logic levels or binary waveforms applied to the four input terminals
• Observe the operation of the circuit by probing the pins of the digital IC with a virtual oscillocope

Elements of the Display

The important parts of the screen display are:

Starting and Ending a Project

• To start a given project, simply click the name of the circuit on the menu that is located on the left side of the screen.
• To end a project, you can either select another circuit or the Quit item from the menu.

Selecting the Inputs for the Circuit

Note that there are four input terminals (labeled A, B, C, and D) located on the virtual circuit board. These labels correspond to the lables for the input terminals on the circuit diagram. You can select the type of input that is applied to each of these input terminals.

To select an input, place the mouse pointer over the desired input terminal and repeatedly click the left mouse key until the designation for the desired type of input appears on the terminal.

There are two usual logic levels--0 and 1

And there are four binary waveforms.  They are rectangular waveforms that switch between the 0 and 1 logic levels. They all have a 50% duty cycle, but differ in their frequency.

Observing the Circuit's Logic Levels and Waveforms

The pins on the virtual IC device are "live," and the mouse is your oscilloscope probe. To observe the operation of the circuit, move the mouse pointer over the desired IC pin and press down the left mouse button. The logic level or waveform will appear on the oscillocope display. The action is much like touching the pin with an oscilloscope probe.