Page 1084 - Basic Electrical Engineering
P. 1084
The theorem states how an AND operation can be converted into an OR
operation, as long as a NOT operation is available. The theorem is usually
expressed in two equations as
and
De Morgan’s theorem has a practical use in digital electronics. Any logic
circuit may be implemented by the basic gates described earlier. A designer
may eliminate the use of more ICs by substituting gates with the equivalent
combination of other gates wherever possible. De Morgan’s theorem
basically implies that any Boolean operation may be simulated with NAND
or NOR gates.
16.8 COMBINATIONAL CIRCUITS
Combinational logic circuits are constructed by interconnecting different
logic gates. A combinational circuit with its truth table has been shown in
Fig. 16.7. The same circuit can also be implemented using NAND gates only
as shown in Fig. 16.7 (b).
The logic gates and related Boolean equations are shown in tabular form in
Table 16.1.
