Binary Adder
Binary adder is a digital circuit that adds two binary numbers and produces the sum. It can be constructed by connecting full adders in cascade where output carry of each full adder should be given as input carry to next full adder.
Four Bit Adder
Following figure shows the four-bit binary ripple carry adder. It is an interconnection of four
full-adder circuits. The bits of augend A and addend B are designated by subscript numbers from right to left. Obviously subscript 0 denotes the least significant bit.