A logic gate truth table is a tabular representation that shows the output of a logic gate based on all possible combinations of input values. Logic gates are fundamental building blocks of digital circuits, and they perform logical operations (AND, OR, NOT, etc.) on binary input values (0 and 1) to produce an output.
The truth table displays all possible input combinations and their corresponding output values, indicating the logical behavior of the gate. The number of rows in a truth table depends on the number of input variables. For a logic gate with 'n' input variables, there will be 2^n rows in the truth table.
Let's take a look at the truth tables for three basic logic gates: AND, OR, and NOT.
AND gate truth table:
The AND gate takes two input values and produces an output of 1 only when both inputs are 1.
Input A Input B Output
0 0 0
0 1 0
1 0 0
1 1 1
OR gate truth table:
The OR gate takes two input values and produces an output of 1 when at least one input is 1.
Input A Input B Output
0 0 0
0 1 1
1 0 1
1 1 1
NOT gate truth table:
The NOT gate takes a single input value and produces the complement of that value (0 becomes 1, and 1 becomes 0).
Input Output
0 1
1 0
These truth tables form the foundation of digital logic, and by combining different gates, complex logic operations can be achieved. Digital circuits, such as microprocessors and memory units, are built using these logic gates to process and manipulate binary data.