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Analogue integrated circuits
an application in which a gain like this is required? — and
besides, as each device has a different gain it would be well
nigh impossible to build two circuits with identical properties,
let alone the mass-produced thousands of radios, TVs,
record players and so on which use amplifiers. So we need
some way of taming this high gain, at the same time as defining
its value precisely, so that useful and accurate amplifiers
may be designed.
The process used in this taming of op-amps is known as feedback
i.e., part of the output signal from the op-amp is fed back
to the input. Look closely again at the circuits we have built so
far this chapter and you’ll see that in all cases there is some
connection or other from the output back to the input. These
connections form the necessary feedback paths which reduce
the amplifier’s gain to a determined, precise level.
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