Page 89 - ComputerScience_Class_11

B. Fill in the blanks.
1. The Boolean expression of two variables NAND gate represented by variables A and B is ………………… .
2. The gate produced by inverting the XOR gate is ………………… .
3. ………………… NAND gates in series is equivalent to AND gate.
4. NAND and NOR gates are called ………………… gates.

5. ………………… is a unary gate.
6. A → B is equivalent to ………………… .
7. (A → B).(B → A) is an expression for ………………… .
8. Compound propositions are joined by ………………… .
9. A.0 = 0 is an example of ………………… .
10. The sum term of a half adder is equal to two variables ………………… gate.

Answers
1. (A.B)' 2. XNOR 3. Two 4. universal 5. NOT
6. A'+B 7. biconditional 8. connectives 9. contradiction 10. XOR

C. Answer the following questions:
1. Draw the truth tables for conditional and biconditional.
Ans. a b a → b a ↔ b
0 0 1 1
0 1 1 0
1 0 0 0
1 1 1 1
2. Draw the logic circuit diagram of the following Boolean expressions using AND and OR gates. Assume complement is available as
input.
a. (B'+D).(A'+D').(B+C'+D') b. (B'.C'+A.C)'
Ans. a.
B' (B'+D)

D

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

D'

B
C' (B+C'+D')
D' = ((A+B)')'
= (A + B)

b. B' B'.C'

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

A
C A.C

Propositional Logic, Hardware Implementation, Arithmetic Operations 87