question_answer 18)

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

Answer:

Let  be the output which appears at the first operation of NOR gate. Then                                                ...(1) This output is fed into an other NOR gate so that Now using Boolean Algebra,  (using eqn. (1)) = A + B  which is an OR operation. the circuit is an OR gate and its truth lable is

A	B	Y
0	0	0
1	0	1
0	1	1
1	1	1