Page 5 - Discrete Mathematics

FINDING A BOOLEAN EXPRESSION FOR A CIRCUIT

P
OR
Q
AND

R OR

SOLUTION:
Trace through the circuit from left to right, writing down the output of each logic gate.

P PQ
OR
Q (PQ)  (PR)

PR AND

R OR

Hence (PQ) (PR) is the Boolean expression for this circuit.
CIRCUIT CORRESPONDING TO A BOOLEAN EXPRESSION
EXERCISE
Construct circuit for the Boolean expression (PQ)  ~R
SOLUTION

P P  Q

Q AND (P  Q)  ~R

OR
~R
R NOT

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