Page 47 - Basics of Electrical, Electronic and Communication

258 Chapter 13. Digital Systems

A

A
B
Y
B

B
C

Figure 13.20:

Solution

A
A
A + (A + B)
A
B
A + B
Y = (A + (A + B)) (B + (B + C))
B
B
B B + (B + C)
C B + C

Figure 13.21:

From the circuit shown in Figure 13.21 we get the output expres-
sion
Y = (A + A + B)(B + B + C)
Using De Morgan’s law,
= (A + A + B) + (B + B + C)
= (A).(A + B) + (B).(B + C)
= A.(A + B) + B.(B + C)
= A.A + A. B + B.B + B.C

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