Logisim - Simulate Digital Logic Circuits

The understanding of electronic circuit designs is actually a part of the curriculum as early as high school. In many vocational classes, understanding electrical circuits or electronic logic is an important first step for a future education in the technical field.

Unfortunately, when it comes to circuitry and electronics, there aren't many free educational tools that are available to educators. However, there is a free software package called Logisim that lets students put together various electrical circuits, and then test their operation in a systematic way.

A free circuit logic simulator allows even schools with a very low budget to provide students with an environment for learning about electrical circuits and logic. A simulator allows an educator to offer an electronics lab environment inside of a computer lab.


Main Logism Screen


When first running Logism, the student is presented with a blank workspace. This is a design area where students can build entire circuit diagrams from scratch. The menu system provides a quick navigation between diagram types, recently used symbols and quick tools.


A Library of Wiring Symbols


The software comes with a very wide range of circuit design symbols to use as part of the test circuit diagram. Symbols include power, transistors and resistors, multiplexers, logic gates and much more.

To use a symbol, all students have to do is right click on one of them and then click inside the design area to place the symbol.


Drawing Circuit Diagrams


Connecting components and drawing the diagrams is as simple as clicking on the component terminals and drawing connections with the mouse. If the simulator is enabled, each of the lines will highlight in a different color to show whether that section of the circuit is live or not. This color coding is a very easy way for students to see just how each change affects the behavior of the entire circuit.


Gates and Logic Diagrams


The circuit drawing tool and embedded simulator can also handle simple or complex logic diagrams using various gates and plexers. The software calculates the logic diagram and displays the results in the same sort of color code as other electronic diagrams. Connecting output devices, like an LED, also displays the output status by enabling or disabling the device.


The Simulator


The simulator that comes embedded into this software makes the application extremely useful for teaching circuits and logic to students of all ages. The "Simulate" menu item lets students enable or disable active simulation, as well as other control features depending on the type of circuit that's being built.


Regions


The drawing tools also include the ability to embed text into the design. It's important for students to learn good circuit design early, by utilizing accurate and useful labels so that others can understand the design and the logic behind its layout.


Text Quizzes


The software also includes a statistics tool under the "Project" menu option that provides a breakdown of every component that makes up the circuit. This is not only useful for keeping track of components already used as part of the design, but at the completion of the design, it allows students to obtain the real world components needed to fabricate the circuit in real life, if they want to.


Analyzing Circuit Outputs


Among other features of the software, probably the most important is the ability to view and analyze the outputs of the circuit. Logisim not only provides the active status of output components like LEDs or displays, but it also tracks a log of each state. This output log can be found under "Simulate" and clicking on "Logging".

In the logging area, students can click on the "Selection" tab to view all of the available output devices on the circuit diagram.


Output Status Log


Clicking on the "Table" tab provides a history of each change of state for every output device. This lets students compare output behaviors to determine whether the circuit is really behaving in the way that they intended with the design.

Logisim provides teachers and professors with an important, affordable tool to teach electronic circuit design in the classroom. Give Logisim a try a try and start teaching your students about the fascinating world of electronics.