a truth table maps variables to their corresponding outputs when passed into a boolean expression or a switching function.
truth tables have been shown to be the means for describing switching functions. an expression representing a switching function is derived from the table by finding the sum of all the terms that correspond to those combinations (i.e., rows) for which the function assumes the value 1. variable appears in uncomplemented form in the product if it has value 1 in the corresponding combination, and it appears in complemented form if it has value 0.