Digital Electronics: Principles, Devices and Applications

228 Digital ElectronicsCC1 11A1 11BB11ADDFigure 6.21 Solution to example 6.13.Example 6.14Minimizing a given Boolean expression using the Quine–McCluskey tabular method yields the followingprime implicants: −0−0, −1−1, 1−10 and 0−00. Draw the corresponding Karnaugh map.Solution• As is clear from the prime implicants, the expression has four variables. If the variables are assumedto be A, B, C and D, then the given prime implicants correspond to the following terms:1. −0−0 → BD.2. −1−1 → BD.3. 1−10 → ACD.4. 0−00 → ACD.• The Karnaugh map can now be drawn as shown in Fig. 6.22.Example 6.15AB + CD is a simplified Boolean expression of the expression ABCD + ABCD + AB. Determineif there are any ‘don’t care’ entries.SolutionThe expanded version of the given expression is given by the equation