Page 88 - Computer science 868 Class 12
P. 88
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.
8686 Touchpad Computer Science-XII

