Q. 14.14  Write the truth table for the circuit given in Fig. 14.39 below consisting of NOR gates and identify the logic operation (OR, AND, NOT) that this circuit is performing.
(Hint:    then 
 and  in the end puts of second NOR gate will be 
 and hence 
 Similarly work out the values of  
 for other combinations of 
 and 
 Compare with the truth table of OR, AND, NOT gates and find the correct one.)
                
                  A and B are the input of a NOR gate and the Output of this NOR gate is the Input of another NOR gate whose Output is Y. Hence,
                                                                Y =    
                                                                Y =      .  
Y = A + B
Hence Circuit behaves as an OR gate.
Truth table
| INPUTS | OUTPUT | 
| 00 | 0 | 
| 01 | 1 | 
| 10 | 1 | 
| 11 | 1 |