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In electronics, an adder or summer is a digital logic circuit that performs addition of numbers. In many computers and other kinds of processors, adders are used not only in the arithmetic logic units Although adders can be constructed for many numerical representations, such as binary-coded decimal or excess-3, the most common adders operate on binary numbers. In cases where two's complement or ones' complement is being used to represent negative numbers, it is trivial to modify an adder into an adder–subtractor. Other signed number representations require a more complex adder. vsr ==Half adder== The half adder adds two single binary digits ''A'' and ''B''. It has two outputs, sum (''S'') and carry (''C''). The carry signal represents an overflow into the next digit of a multi-digit addition. The value of the sum is . The simplest half-adder design, pictured on the right, incorporates an XOR gate for ''S'' and an AND gate for ''C''. With the addition of an OR gate to combine their carry outputs, two half adders can be combined to make a full adder. The half adder adds two input bits and generates a carry and sum, which are the two outputs of a half adder. The input variables 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Adder (electronics)」の詳細全文を読む スポンサード リンク
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