This article is about NOR Logic in the sense of building other logic gates using just NOR gates. For NOR gates, see NOR gate. For NOR in the purely logical sense, see Logical NOR. For logic gates in general, see Logic Gate.
This is made by joining the inputs of a NOR gate. As a NOR gate is equivalent to an OR gate leading to NOT gate, this automatically sees to the "OR" part of the NOR gate, eliminating it from consideration and leaving only the NOT part.
An XOR gate is made by connecting the output of 3 NOR gates (connected as an AND gate) and the output of a NOR gate to the respective inputs of a NOR gate. This expresses the logical formula (A AND B) NOR (A NOR B). This construction entails a propagation delay three times that of a single NOR gate.
An XNOR gate can be constructed from four NOR gates implementing the expression "(A NOR N) NOR (B NOR N) where N = A NOR B".This construction has a propagation delay three times that of a single NOR gate, and uses more gates.