Page 88 - Computer science 868 Class 12
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A                A.B
                                               B
                                                                               A'.B'+A.B


                                              A'               A'.B'

                                               B'


                  6.  Write the boolean expression of  (1), (2), (3) and (4) for the following logic circuit diagram:

                                      A                            (1)

                                      B


                                                                   (2)                    (4)

                                      C


                                                                    (3)


                Ans.  1. (A+B)
                     2. (A+C')
                    3. (A'+C')
                    4. (A+B).(A+C').(A'+C')
                  7.  a. Draw (A+B).(A+C').(A'+C') using NOR gate only.
                     b. Draw a circuit with AND/OR gates and replace it with NOR.
                Ans.
                     A              (A+B)'

                     B


                     A
                                     (A+C)'            (A+B).(A+C).(A'+C')
                     C


                    A'              (A'+C)'
                    C'


                     ((A+B)'+(A+C')'+(A'+C')')'
                     = (A+B)".(A+C')".(A'+C')"
                     = (A+B).(A+C').(A'+C')
                  8.  Draw (A+B).(A+C').(A'+C') using NAND gate only.
                     a. Draw a circuit taking the complement of the inputs with AND/OR gates and replace with NAND gate.
                     b. Complement with another NAND gate.








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