NOR gate truth table and circuit diagram with 3 inputs

NOR gate is one of the universal logic gates other than NAND gate. NOR gate contains an OR gate and a NOT gate in series.This suggests that a NOR gate can give the inverted output of an OR gate. In this article, we are going to discuss the circuit diagram, Boolean expression and truth table of NOR gate using two inputs and three inputs.

What is a NOR gate?

A NOR gate consists of an OR gate and a NOT gate in series. NOR gate is a logic gate that gives the output as the complement of the sum of the inputs. So, the output of a NOR gate is the complement of the output of an OR gate with the same inputs. Therefore, NOR gate is the inverter of OR gate.

Boolean expression of NOR gate

A NOR gate can have an infinite number of inputs and only one output. If A, B, C, D….. etc. be the inputs of a NOR gate then the expression for the Boolean output of the NOR logic is \small \textbf{Y=} \overline{\textbf{A+B+C+D}}.

Logic circuit of 2 input NOR gate

This is the circuit symbol of NOR gate with 2 inputs A and B. Here, Y is the output. NOR gate consists of an OR gate and a NOT gate. The bubble at the head of the symbol comes from the NOT gate and the rest are from the OR gate.

Truth table of two input NOR gate

Here is the truth table for a NOR gate with two inputs A and B. Y represents the output of the gate.

Input (A)	Input (B)	Output \small \textbf{Y=} \overline{\textbf{A+B}}
0	0	1
0	1	0
1	0	0
1	1	0

Circuit diagram of NOR gate with 3 inputs

Here is the logic circuit of three input NOR gate with the inputs as A, B and C.

Truth table of NOR gate using 3 inputs

Here is the NOR gate truth table with three inputs A, B and C. It gives the inverted output of OR gate.

Input (A)	Input (B)	Input (C)	Output \small \textbf{Y=} \overline{\textbf{A+B+C}}
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

Uses of NOR logic

1. NOR gate is one of the universal logic gates which can be utilized to design all other logic gates.
2. NOR gate has applications in memory circuits.
3. The main function of NOR gate is to introduce the inverted output of OR gate.

This is all from this article on NOR gate with its truth table and circuit diagram. If you have any doubt on this topic you can ask me in the comment section. Thank you!

Related posts:

1. Basic logic gates – OR, AND and NOT gate
2. NAND gate
3. XOR gate using NAND gate
4. XNOR gate using NAND gate
5. Boolean algebra
6. Karnaugh map (K-map)