Full Adder

In this assignment, we will build a full adder. A full adder adds 3 bits to produce a sum and carry bit.

Why do we need to add 3 bits ?

Let's understand with an example. The image below shows how we add 2 binary numbers.

Notice the carry bit at the top of the addition. For many columns we actually need to add 3 bits. The 2 actual bits and the carry bit.

This is why we need a Full Adder, which will add 3 bits, to generate a sum and carry bit.

So, how do we implement a full adder? Let us look at the truth table.

A Full Adder seems to be a combination of 2 half adders.

The script is embedded below (I am not showing how I deduced this... but it is documented in my notes on paper)