A NOR gate, also known as a Negated OR gate, does the function of the OR gate, then negates it. This means that if the result was one it would change it to zero and vice versa. A NOR gate also has two or more inputs but only a single output. This negated function is done on the OR gate by putting a small circle at the end of it. As you can see to the right, the symbol is identical to the OR gate but with a little circle.
The Boolean equation of the logic gate is:
^{*The line above the A+B represents a "not" or a negation}
Based on this equation we can find out all possible results of different outputs. This gate can have two or more inputs. Below is the truth table that shows the outputs for all the different input combinations for a twoinput NOR gate.
The truth table and Venn diagram below represent the different inputs and outputs of the gate. For more information on truth tables and Venn diagrams, click here.
Truth Table: NOR Gate  2 Inputs 
Input 
Output 
0 
0 
1 
0 
1 
0 
1 
0 
0 
1 
1 
0 


Below, we have provided GIF animations to represent the function of the gate.


NOR Gate: Input = 00

NOR Gate: Input = 01




OR Gate: Input = 10

NOR Gate: Input = 11

Application
A NOR gate can be used in a variety of different applications. One example of a NOR gate in use is in a mixing machine. Sensors placed on the machine sense whether there is any ingredients left in the machine or not. If any of the ingredients containers are empty and the sensor is activated(1) then the output will be 0 and the mixing will stop.