Adder

Abstract

---

• A Combination Circuit that performs addition

Half Adder

---

• Can be built with one XOR for the current bit & one AND for the carry bit
• Takes in two Bit and return the current bit sum and carry bit cout

Full Adder

---

• Built with two Half Adder, takes in three Bit
• The sum of the first half adder is added with the cin by the second half adder
• The sum output of the second Half Adder is the final sum at that position when there is a carry in bit cin besides the 2 bits of the binary string we need to sum
• For the carry out bit cout, we need to have an OR to pipe out the final cout to handle situation where the first Half Adder’s cout is 1 while the cin is 0 & sum of the first Half Adder is 0