Digital Logic
NOR Gate
A logic gate that outputs the complement of OR—high only when all inputs are low.
Detailed Explanation
NOR (NOT-OR) is also functionally complete. In CMOS, NOR uses NMOS transistors in parallel and PMOS in series. The series PMOS makes NOR slower than NAND for the same transistor sizes.
NOR gates are useful for wired-OR implementations and specific logic structures. Some early computers used NOR-gate-only logic.