Back بوابة فصل منطقي منفي Arabic NOR elementi Azerbaijani Porta NOR Catalan Hradlo NOR Czech NOR-Gatter German Puerta NOR Spanish VÕI-EI Estonian EZ-EDO ate logikoa Basque دروازه نقیض یا Persian NOR-portti Finnish
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| NOR gate truth table | ||
|---|---|---|
| Input | Output | |
| A | B | A NOR B |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
The NOR gate is a digital logic gate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output (1) results if both the inputs to the gate are LOW (0); if one or both input is HIGH (1), a LOW output (0) results. NOR is the result of the negation of the OR operator. It can also in some senses be seen as the inverse of an AND gate. NOR is a functionally complete operation—NOR gates can be combined to generate any other logical function. It shares this property with the NAND gate. By contrast, the OR operator is monotonic as it can only change LOW to HIGH but not vice versa.
In most, but not all, circuit implementations, the negation comes for free—including CMOS and TTL. In such logic families, OR is the more complicated operation; it may use a NOR followed by a NOT. A significant exception is some forms of the domino logic family.
It is because of their diversity that NOR and NAND gates are used more than any other gates in the processor design. As both of these gates can be used to replicate any other gate they are produced in much higher numbers than other logic gates. This makes them cheaper to buy, which is another factor causing them to be the most popular of gates.