31.
33. For a function to be performed, a MINTERM EXPRESSION
a. A(A+B) = A
1
can be derived for each output column from a truth table.
1
1
One output column is taken at a time, and a Boolean product
is written for each output condition that is a 1. After the
b. is
Boolean product which represents each 1 output is written,
the outputs are ORed together to form a MINTERM
EXPRESSION. For example, the diagram below is the truth
table for a circuit that will add two binary digits.
INPUTS
OUTPUT
A
B
SUM
CARRY
0
0
0
0
0
1
1
0
1
0
1
0
1
1
0
1
32
To derive a MINTERM EXPRESSION for each output
E
F SUM CARRY
0
0
0
0
0
1
1
0
column, the Boolean product is written for each 1 output.
1
0
1
0
1
1
0
1
Use only one output column at a time. The Boolean product
for the SUM-output column is derived as follows:
The first 1 occurs when A is 0 and B is 1; thus, the Boolean
product for this condition is AB.
The next 1 occurs when A is 1 and B is 0; thus, the Boolean
product for this condition is AB.
IT 0346
1-22
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