SCEN103 Computer Lab Combinational Logic with Electronics Workbench

Contents

Logic Gates   Logic Converter   The Exercises

Objectives
Gain experience with logic circuits

Combinational Logic with EWB
In Electronics Workbench, the parts bin of logic gates includes both schematic representation of gates as well as integrated circuit packages of gates (the bottom row of the parts bin). For this exercise, rely on the first seven gates enclosed in the first row: AND, OR, NOT, NOR, NAND, XOR, and XNOR. Be careful to ignore the labeling on the gate packages in the second row where the gates are ordered differently than the first row.

logic gates

Logic gates dragged from the parts bin will have two inputs. Additional inputs may be added by right-clicking on the desired gate, selecting "Component Properties", then "Number of Inputs".

logic gates with multiple inputs

EWB Logic Converter
Electronics Workbench conveniently provides an instrument called the Logic Converter which will create a truth table for a combination of gates. After the desired gate combination has been assembled, connect the inputs of the gates to the inputs A-H of the converter, followed by connection of the output.

After dragging the instrument to the worksheet, duble-click on the instrument icon to bring up the panel view; logic converter
On the expanded front panel of the instrument, click on the gate-to-truth-table button to create or update the truth table. logic converter

Here is an example of a gate combination and its truth table constructed with the Logic Converter:

logic converter in operation

The Exercises
For the following exercises, print out the schematic of the combination of gates used along with the truth table presented by the Logic Converter.

Homework Confirmation
Use Electronics Workbench to confirm your solutions to the combinational logic homework assignment.


"http://www.physics.udel.edu/~watson/scen103/lab/logic.html"
Last updated May 12, 1999.
Copyright George Watson, Univ. of Delaware, 1999.