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Unformatted text preview: Boolean Algebra Questions: 1. Is A' + B' = (A+B)' ??? 2. Is A'B' = (AB)' ??? Answers: Create the truth tables for each side of the equation to find out if they are equal. Q: Why would anybody care if two circuits are equivalent? A: One may be cheaper to build! Logical equivalence: Two circuits are logically equivalent if they produce identical outputs for all possible combinations of their inputs. Testing for logical equivalence: One way is to build a truth table for each function and compare the results. Example Does (AB)' = A'B' ??? A B A' B' AB (AB)' A'B' 1 1 1 1 1 1 1 1 1 1 1 1 1 The last two columns are NOT equal! There is a limit to the number of possible circuits that we can build with only 2 inputs (there are 16 – we looked at all 16 last class period). Some more interesting functions are those that have more than two inputs. However, with 3 inputs, there are 2 raised to the 2 3 = 2 8 = 256 possible functions....
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- Fall '09
- Boolean Algebra, DeMorgan, a+b, Absorption law