Page 99 - Computer science 868 Class 12
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A A A D D D D D D D D
2 1 0 0 1 2 3 4 5 6 7
0 0 0 1 0 0 0 0 0 0 0
0 0 1 0 1 0 0 0 0 0 0
0 1 0 0 0 1 0 0 0 0 0
0 1 1 0 0 0 1 0 0 0 0
1 0 0 0 0 0 0 1 0 0 0
1 0 1 0 0 0 0 0 1 0 0
1 1 0 0 0 0 0 0 0 1 0
1 1 1 0 0 0 0 0 0 0 1
The logic circuit diagram for a 3 to 8 decoder.
Ans. A A A
2 1 0
D 0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
To draw the logic circuit diagram of a 3 to 8 decoder, all three input variables are connected both directly and through the NOT
gate to get the complemented input. The input variables are connected to eight AND gates. Only one AND gate produces High
output(1) for a particular input combination and represents the corresponding Octal number, while the other AND gates are 0
28. From the logic circuit diagram given below, derive the Boolean expression and simplify it to show that it represents a logic gate.
Name and draw the logic gate. [ISC 2019]
X
Y
F
Z
Ans.
X
X+Y
Y
(X+Y).X.Z
Z X.Z
(X+Y).X.Z
97
Computer Hardware 97

