What is a Logic Circuit?
A logic circuit is a set of gates joined together to produce a specific output from given inputs.
Boolean Functions and Truth Tables
A Boolean function is an expression formed with binary variables and logical operators (OR, AND, NOT) with an equality sign. A truth table is a list that defines a Boolean function.
Example: X = A·B + A·C
With 3 inputs, there are 23 (i.e. 8) possible combinations of 1s and 0s:
| A | B | C | A·B | A·C | A·B + A·C |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 0 | 0 | 0 |
| 0 | 1 | 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 0 | 0 | 0 |
| 1 | 0 | 0 | 0 | 0 | 0 |
| 1 | 0 | 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 1 | 0 | 1 |
| 1 | 1 | 1 | 1 | 1 | 1 |
