However, the two functions of AND and OR on their own do not form a complete logic set. Similarly cascading an OR and NOT gate together will produce a NOR gate, and so on. Likewise, the set of OR and NOT can be used to create the AND function.Īny logic gate which can be combined into a set to realise all other logical functions is said to be a universal gate with a complete logic set being a group of gates that can be used to form any other logic function.įor example, AND and NOT constitute a complete set of logic, as does OR and NOT as cascading together an AND with a NOT gate would give us a NAND gate. In fact, it is possible to produce every other Boolean function using just the set of AND and NOT gates since the OR function can be created using just these two gates. As we have seen throught this Digital Logic tutorial section, the three most basic logic gates are the: AND, OR and NOT gates, and given this set of logic gates it is possible to implement all of the possible Boolean switching functions, thus making them a “full set” of Universal Logic Gates.īy using logical sets in this way, the various laws and theorems of Boolean Algebra can be implemented with a complete set of logic gates. Individual logic gates can be connected together to form a variety of different switching functions and combinational logic circuits.

Logic gates equation