INTRODUCTION:
A logic gate is an elementary building block
of a digital circuit. Most logic gates have
two inputs and one output. At any given
moment, every terminal is in one of the
two binary conditions low (0) or high (1),
represented by different voltage levels.
The logic state of a terminal can, and generally
does, change often, as the circuit processes
data. In most logic gates, the low state
is approximately zero volts (0 V), while
the high state is approximately five volts
positive (+5 V).
Using combinations of logic gates, complex
operations can be performed. In theory,
there is no limit to the number of gates
that can be arrayed together in a single
device. But in practice, there is a limit
to the number of gates that can be packed
into a given physical space. Arrays of
logic gates are found in digital integrated
circuits (ICs). As IC technology advances,
the required physical volume for each
individual logic gate decreases and digital
devices of the same or smaller size become
capable of performing ever-more-complicated
operations at ever-increasing speeds.
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