NOR Gate:
The logic NOR gate is the combination of two gates which is called OR gate and Not gate connecting together Is series form:
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A NOR gate is sometimes known as a "general purpose" gate.
NOR gates, like NAND gates, can be used to generate any other kind of logic gate function. A NOR gate logic or Boolean expression is an expression for the logical multiplication that it performs on the complement of the inputs.
A+B = Q