Kmaps

To use a Kmaps to simplify an expression described by a truth table, we need to complete the following 4 steps:

1. Notice how many variables the expression/truth table contains, and select the correct Kmap based on this number.
2. Fill the cells of the Kmap with $1$s and $0$s according to column $E$ in the truth table.
3. Encircle groups of adjacent cells of $1$s, and
4. Write down the expression corresponding to those groups of $1$s.

Let's explain how to complete each of these steps:

1. Given a truth table, check how many variables are involved. The number of variables is equal to the number of columns in the truth table minus 1 (since we don't count the column for $E$ as a variable.) Then, pick up the right Kmap to use (either a 2-variable, 3-variable, or 4-variable Kmap.)
   • For example, if the truth table describes an expression using $x$ and $y$, use a 2-variable Kmap.