39. ABK + ABK

+ ABK + ABK

Veitch diagram, the final step in designing logic circuits,

using Boolean algebra, is to draw the appropriate logic

diagram to represent the simplified expression. The sum

expression and the carry expression for a circuit which will

add two binary digits are

AB + AB SUM EXPRESSION

AB

CARRY EXPRESSION

Since there are two outputs consisting of (1) the sum output

and (2) the carry output, the logic diagram must show two

outputs when completed.

40. a. X(X+Y) =X

To diagram the sum output, first recognize the expression

1

AB + AB as an overall two-input OR circuit containing inputs

1

1

AB and AB. The first step in drawing the logic diagram is

b. Yes

shown below.

Diagram each input and draw the appropriate logic symbols

as follows: