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Boolean Algebra - Etsu

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Chapter 5: <strong>Boolean</strong> <strong>Algebra</strong> 99gate outputs a 1 if its inputs are different and a zero if its inputs are thesame.If one of the inputs to a two-input XOR gate is connected to a logic0, then the gate's output follows the value at the second input. In otherwords, if the second input is a zero, the inputs are the same forcing theoutput to be zero and if the second input is a one, the inputs aredifferent and the output equals one.Rule: A ⊕ 0 = AA A ⊕ 00 0 ⊕ 0 = 01 1 ⊕ 0 = 1If one input of a two-input XOR gate is connected to a logic 1, thenthe XOR gate acts as an inverter as shown in the table below.Rule: A ⊕ 1 = AA A ⊕ 10 0 ⊕ 1 = 11 1 ⊕ 1 = 0If the same operand is connected to both inputs of a two-input XORgate, then the inputs are always the same and the gate outputs a 0.Rule: A ⊕ A = 0A A ⊕ A0 0 ⊕ 0 = 01 1 ⊕ 1 = 0Lastly, if the inputs of a two-input XOR gate are inverses of eachother, then the inputs are always different and the output is 1.Rule: A ⊕ A = 1A A ⊕ A0 0 ⊕ 1 = 11 1 ⊕ 0 = 15.5.5 Derivation of Other RulesIf we combine the NOT, OR, and AND rules with the commutative,associative, and distributive laws, we can derive other rules for booleanalgebra. This can be shown with the following example.ExampleProve that A + A·B = A

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