Full adder

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Goal

  • First step into logic.

Level

  • Knowing how to use a breadboard

Component

  • two nand gate array chip (I used the ???).

How to

The logic circuit of the chip is as followed :

Adderlogic.gif

From this chip, we will make an half adder. It is one of the basic component of every CPU as it is adding two bits. It's use is to have two bits. They represent a state either 1 or 0. We will add them with the following scheme :

1 + 1 = 10
1 + 0 = 01
0 + 1 = 01
0 + 0 = 00
^ this bit is the first bit we add, we will call it A later on.
    ^ this bit is the second bit we add, we will call it B later on.
        ^ this bit is the most significant bit. We call it C1 later on.
         ^ this bit is the least significant bit. We call it C0 later on.

Just follow the schema. You will need two chip to implement the half adder.

Halfadder.gif

What is happening there ?