LOGIC GATES
There are three basic logic gates from which others can be made, namely:
(1) The NOT GATE
(2) The AND GATE
(3) The OR GATE
THE NOT GATE
This gate negates the value of data or signal at its input. It will always output the opposite signal.
| INPUT | OUTPUT |
| A
0 1 |
B
1 0 |
Not gate truth table
THE AND GATE
This gate requires at least two data or signal lines and performs the AND Boolean operation on them to produce a single output.Thus, if both or all input are true, the output is true. Also, if any input A or B is false, then result C will be false.
| INPUT | OUTPUT | |
| A
0 0 1 1 |
B
0 1 0 1 |
C
0 0 0 1 |
AND gate truth table
THE OR GATE
This gate will produce a single output that is true for any of the input that is true.
| INPUT | OUTPUT |
| A B
0 0 0 1 1 0 1 1 |
C
0 1 1 1 |
Or gate truth table
THE NAND GATE
A logic gate that creates the function of the logical operator NAND. Also, it could be said to be a logical gate that produces an output that is the inverse of the output of an AND gate.
THE X OR GATE
It is a logic gate that carries out exclusive (total) disjunction (disconnection). It behaves according to the truth table to the right. A HIGH output (1) result if one and only one of the inputs to the gate is HIGH (1) if both inputs are LOW (0) or both are HIGH (1), a LOW output (0) results (e.g. (MOS4030).