Students,
    For some of the upcoming labs, you may find it nice to be able to simulate and debug your designs before actually wiring up the design on your breadboard. You don't have to, but finding errors can be difficult, especially when you're not sure if the error is due to a mistake in your logic or just a simple wiring mix-up.

    You can download an easy-to-use simulation tool from http://sourceforge.net/projects/circuitsandbox. With this software, you can build your design using a 'drag-and-drop' interface, and then interactively simulate it to verify correctness. The software is written in Java, and thus should run on Windows, Linux, or MacOS.

    I've attached a sample file containing the NAND circuit from Lab 1, Figure 1 as an example.

-- David