Experiment 21 - The 3-Input AND Gate with 2-Input AND Gates

With the AND logic you can combine 3 inputs. For this you can use 2 input AND gates...

Due to the associative law of the Boolean Algebra you are able to construct a 3-input AND gate using two 2-input AND gates.

The truth table remains unchanged...

A B C Q 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 1 Truth Table of the 3-input AND logic.

Logic diagram 3-input AND gate.

Circuit 3-input AND logic with 2-input AND gates. (Enlarge)

With two of the four AND gates on the C-MOS IC 4081 you can replicate the 3 input AND logic with the circuit shown.