NOR Gate Logism; Very Well Explained
A logic NOR gate is a digital logic gate with two or more inputs and one output that performs logical NOR. The output of a NOR gate is true when all of its inputs are false. The symbol for a NOR gate is an upside-down ‘OR’ symbol.
Logic NOR Gate Truth Table.
2 input NOR gate truth table.
The truth table of a logic NOR gate shows how it behaves based on the inputs it receives. In the table below, the inputs are labelled A and B, and the output is labelled Q.
| A | B | Q |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
From the truth table, it is easy to see that the output of a NOR gate is 1 (true) only when both of its inputs are 0 (false).
3 input NOR gate truth table.
| A | B | C | Q |
|---|---|---|---|
| 0 | 0 | 0 | 1 |
| 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 | 0 |
How a Logic NOR Gate Works
A logic NOR gate works by combining the inputs it receives through an OR operation. The output of the OR operation is then inverted, resulting in the output of the NOR gate.
For example, if the two inputs of a NOR gate are A and B, the output of the OR operation would be A+B. This output is then inverted, resulting in the output of the NOR gate, which would be A+B’.
Uses of a Logic NOR Gate.
A logic NOR gate is an electronic device used to implement logical operations on two or more inputs. It is a combination of an OR gate and a NOT gate, and its output is the inverse of the OR gate’s output. The logic NOR gate is also known as an OR-NOT gate, or an inverter-OR gate.
The logic NOR gate is used in a variety of applications, including
- digital logic,
- computer architecture, and
- circuit design.
In digital logic, the NOR gate is used to implement the Boolean function of “not A and not B.” This function is used in logic circuits to ensure that only one input is true for a given output. For example, if the inputs are A and B, then the output will be true only if both A and B are false.
In computer architecture, the NOR gate is used to implement a multiplexer, which is a device that allows multiple signals to be combined into a single output. Multiplexers are especially useful in electronic systems such as computers, where they can be used to control the flow of information.
In circuit design, the NOR gate can be used to control the flow of current. For example, it can be used to control the flow of current through a transistor, by using the output of the NOR gate to turn the transistor on or off. This allows the designer to control the current flow with a single signal.
The logic NOR gate is also used in digital logic circuits to create a latch. A latch is a device that is used to store a value until it is reset. This is useful in applications such as digital clocks and counters, which require a device to maintain a count even when power is removed.
In summary, the logic NOR gate is a versatile device that is used in a variety of applications, ranging from digital logic to circuit design. It is used to implement the Boolean function of “not A and not B”, to control the flow of information in computer systems, and to control the flow of current in circuit designs.
Different logic gates that only use NOR gates.
Exclusive-OR, Exclusive-NOR, and standard NOR gates can also be created using just individual NOR gates, in addition to the three commonly used types mentioned above.
Commonly available digital logic NOR gate IC’s include:
TTL Logic NOR Gates
- 74LS02 Quad 2-input
- 74LS27 Triple 3-input
- 74LS260 Dual 4-input
CMOS Logic NOR Gates
- CD4001 Quad 2-input
- CD4025 Triple 3-input
- CD4002 Dual 4-input
How do you convert the NAND gate to the NOR gate?
We must invert all inputs and the output to convert a NAND gate into a NOR, much like how we converted a NOR gate into a NAND.
How do you wire a NOR gate?
A NOR gate can be wired using two inputs, an output, and two resistors. The inputs of the NOR gate should be connected to one resistor each, with the other end of the resistors connected to the output. The output should also be connected to ground.
Is NOR gate universal?
The NOR gate can be categorized as a “Universal” type gate, just like the NAND gate seen in the previous section. Similar to the NAND gate, NOR gates can be used to create any other type of logic gate function.
For instance, the three fundamental gate types of AND, OR, and NOT function can be created using only NOR gates by connecting them together in different combinations.
RLC talk
