The most fundamental kind of logic gates are AND, OR, and NOT. They are the most fundamental components of every logic or digital circuit. This “Full Set” of Universal Logical Gates, which consists of the logic gates AND, OR, and NOT, performs each fundamental logic operation separately. However, OR and AND logic gate functions may also be performed using combinations of AND and NOT or OR and NOT logic gate sets respectively. This article discusses universal logic gate and different sets in detail.
Universal Logic Gates and Sets
The NOR and NAND logical gates are called Universal Logic Gates. These gates can be used to create all of the other types of logical functions as well as the other types of Boolean expressions. The “Set” category includes the logic gates that can create many other forms of logic functions as well as different Boolean expressions. Similarly, an OR+NOT gate set is used to create AND Gate logic as shown below:
Types of Logic Gates Sets
Full Set:
Full set means all the three fundamental logic gate operations of multiplication, addition or complement of inputs shall be performed by combinations of logic gates. These include fundamental logic gates of AND, OR and NOT gates.
Complete Set:
While the fundamental operations are performed individually in the case of full set, the complete set makes use of indirect type of gate combinations to perform these fundamental operations. The complete set includes AND+NOT gates combination and OR+NOT gates combination.
Minimal Set:
The minimum set comprises NOR and NAND gates. Any NAND or NOR gate can be used individually to construct three fundamental logic gate operations. Due to the minimum number of gates involved, these are known as minimal sets.
Summary of Logic Gate Sets
The summarized description and building components of five sets of logic gates is provided below:
AND & NOT COMPLETE SET
The fundamental logic gates are constructed in the below diagram utilizing AND and NOT gates. The gates are comparable to AND/NOT gate sets.\
OR and NOT COMPLETE SET
The fundamental logic gates in the below diagram are created just utilizing OR and NOT gates. The gates are comparable to OR/NOT set.
AND, OR AND NOT FULL SET
Every logic function and Boolean expression can be created using AND, OR, and NOT gates (Full Set). An exclusive-OR (XOR) logic gate is built utilizing gates from the Full Set in the following diagram.
The following figure shows how an exclusive-NOR (XNOR) logic gate is built using a Full Set.
NAND Gates Based Minimal Set
All other logic operations can be constructed by NAND gates only as shown in the diagram below. Four distinct NAND gates are used in the diagram. These four NAND gates packages are commercially available in 74LS00 IC.
NOR Gates Based Minimal Set
NOR gates are used as minimal sets in the following diagram. Four distinct NOR gates are included as available in the 74LS02 IC.
Comparison of Minimal Sets
The two types of minimal sets make it clear that either five (05) NOR gates or four (04) NAND gates are needed to build an Exclusive-OR gate. Therefore, as compared to five (05) of NOR gates, the Exclusive-OR (XOR) gate made using four (4) NAND gates is more effective.
Conclusion
All the logic operations or Boolean expressions may be created via Universal Logic Gates. The fundamental gates of AND, OR, and NOT may construct any logical or Boolean expression. However, logic gate sets are made up of combination of logic gate(s) that can create fundamental logics. These indirect combinations of gates can be regarded as full set, complete set, and minimal gate sets.
