ic
Section 8.2 Logic Networks
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Networks and Expressions
It’s time to see how these ideas of logic gates, Boolean expressions, and truth
functions are related. By combining AND gates, OR gates, and inverters, we can
construct a logic network representing a given Boolean expression that produces
the same truth function as that expression.
example 11
The logic network for the Boolean expression x 1 x 2
′ + x 3 is shown in Figure 8.8.
figure 8.8
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PraCtiCe 9 Design the logic network for the following Boolean expressions.
a. x 1 + x 2
′
b. x 1 (x 2 + x 3 )′
Conversely, if we have a logic network, we can write a Boolean expression
with the same truth function.
example 12
A Boolean expression for the logic network in Figure 8.9 is
(x 1 x 2 + x 3 )′ + x 3
figure 8.9
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PraCtiCe 10
a. Write a Boolean expression for the logic network in Figure 8.10.
figure 8.10
b. Write the truth function (in table form) for the network (and expression) of part (a).