Write the truth table for circuit given in figure, below consisting of NOR gates and identify the logic operation( OR,AND,NOT) which this circuit is performing.

Explanation

A=0,B=1 then A and B inputs of second NOR gate willbe 0 and hence Y =1 . Similarly work out the values of Y for other combination of A and B .Compare with the truth table of OR, AND , NOT gates and find the correct one .

C is the output of OR gate 1.
D is the output of NOT gate 1 and input of NOT gate 2.E is the outputof OR gate 2 and input of the NOT gate 2.Here, it is same asOR gate. A and B are inputs and Y is output.

So, this logic operation resembles to OR gate.