The teaching of scientific subjects usually require laboratories where students can put the theory they have learned into practice. Traditionally, electronic programmable calculators, dedicated software, or expensive software simulation packages, such as MATLAB have been used to simulate scientific experiments. Recently, spreadsheet programs have replaced the electronic calculators and are now widely used by science, engineering and mathematics education in modelling and solving complex problems. One of the advantages of a spreadsheet application in science education is that a given problem can easily be modelled and then simulated with varying parameters. The change of the output can then easily be displayed in graphical format as the simulation progresses. This paper describes how spreadsheet programs such as Microsoft Excel can be used for the simulation of digital logic circuits thought to undergraduate students. (Contains 4 figures.)