Unformatted text preview: What about the Boolean expression for this circuit? Since the circuit produces two distinct output values, we represent it using two Boolean expressions: sum = A ⊕ B carry = AB Note that a half adder does not take into account a possible carry value into the calculation (carry-in). That is, a half adder is fine for adding two single digits, but it cannot be used as is to compute the sum of two binary values with multiple digits each. A circuit called a full adder takes the carry-in value into account. We can use two half adders to make a full adder. How? Well, the input to the sum must be the carry-in and the sum from adding the two input Sum Carry A B A 1 1 B 1 1 Sum 1 1 Carry 1...
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- Fall '10