NOR Gate

The output is high only when neither A nor B is high. That is, it is normally high but any kind of non-zero input will take it low.

The NOR gate and the NAND gate can be said to be universal gates since combinations of them can be used to accomplish any of the basic operations and can thus produce an inverter, an OR gate or an AND gate. The non-inverting gates do not have this versatility since they can't produce an invert.

NOR Gate Operations

The NOR gate is called a universal gate because combinations of it can be used to accomplish all the basic functions.

IC 7402 Quad NOR Gate