Any complex digital circuit can be built using basic logic gates. Most logic gates have two (or
more) inputs and one output.
The input or output terminal is in one of the two binary conditions
low (0) or high (1), represented by different voltage levels. In most logic gates, the low state is
approximately zero volts (0 V), while the high state is approximately five volts positive (+5 V).
And in this part, we are going to discuss about the basic logic gates, including the AND gate, OR gate, XOR gate, NOT gate, NAND gate, and NOR gate.
1. The AND gate
The AND gate performs the Boolean AND operation, which is applied to the input variables.
Here is the circuit symbol of AND gate and its truth value table
In the picture shown above is the representative circuit of the two-input AND gate.
The truth table of two-input AND gate:
| A | B | A · B |
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
Note: The result is true(1), only if both A and B are "1".
you can make the simulation to prove if it is true or not. I am gonna use PROTUES for my simulation
As you can see, the LED only emits light when both inputs have the value of "1", besides that, The LED remains dark.
2. OR gate
The OR gate performs the Boolean OR operation, which is applied to the input variables.
The truth value table of two-input OR gate is shown below
| A | B | A +B |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
'The result is "0" unless both values of the inputs are "0".
The simulation
Look at the simulation we see that using OR gate, the LED only dark when both values of the input are "0", so others LED are all emit light.
3. NOT gate
The NOT gate performs the NOT Boolean operation on a single input. Thus, it is also called an
inverter.
The two-input NOT gate symbol
The truth table of NOT gate
| A | |
| 0 | 1 |
| 1 | 0 |
Complementing can be accomplished using a NOT gate. Here, “1” is changed to “0” and “0” is
changed to “1”.
The simulation
Can you see the simulation above? when you input the value "0" pass true the NOT gate, you will see the output is HIGH(1) that makes the LED bright. but if you input the input value "1" we see the output is LOW(0) which means that the output become 0. So we can say that the not gate output is opposite from the input.
4. NOR gate
The NOR(Not OR gate) gate performs the Boolean NOR operation, which is applied to the input variables.
The symbol of two-input NOR gate
The truth table of NOR gate
A B A+B 
0 0 0 1
0 1 0 1
1 0 0 1
1 1 1 0
The NOR gate is the gate that outputs the opposite value of the OR gate as you can see in the table above
Now let see the simulation of NOR gate
The simulation of the OR gate
0 1 0 1
1 0 0 1
1 1 1 0
The NOR gate is the gate that outputs the opposite value of the OR gate as you can see in the table above
Now let see the simulation of NOR gate
The simulation of the OR gate
Compare the simulation of the NOR gate and OR gate allowed us to see the differences between them both. in the OR gate if we input the value of "0" we see the LED is off, but in the NOR gate when we input the "0" value pass through the gate, we see the LED is on.
5. NAND gate
The NAND gate performs the Boolean NAND operation, which is applied to the input variables.
0 1 0 1
1 0 0 1
1 1 1 0
The NAND gate truth table has the contrast value to the AND gate.
Simulation
5. NAND gate
The NAND gate performs the Boolean NAND operation, which is applied to the input variables.
The symbol of two-input NAND gate
The truth table of NAND gate
A B A · B
0 0 0 1
0 1 0 1
1 0 0 1
1 1 1 0
The NAND gate truth table has the contrast value to the AND gate.
Simulation
6. XOR gate
The XOR(Exclusive OR gate) gate performs the Boolean XOR operation, which is applied to the input variables.
The XOR(Exclusive OR gate) gate performs the Boolean XOR operation, which is applied to the input variables.
The symbol of two-input XOR gate
The truth table of XOR gate
A B A(+)B
0 0 0
0 1 1
1 0 1
1 1 0
Note:
The result is “1” if A is “0” and B is “1” or vice versa(reverse), that is, A and B are not equal.
7. XNOR gate
The XNOR gate inverts the result obtained by a Boolean XOR operation.
The symbol of XNOR gate
The truth table of XNOR gate
A B A(+)B A XNOR B
0 0 0 1
0 1 1 0
1 0 1 0
1 1 0 1
Note:
The XNOR gate inverts the output of the XOR gate.
The test simulation of XNOR gate
If you have any problem you can give some feedback through the comment down below. Thanks
No comments:
Post a Comment