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Starting electronics
Figure 9.12
page
The breadboard layout of the circuit in Figure 9.11 on the previous
which you can build yourself. But the more inquisitive reader
may have been wondering how the device can do all of this:
after all, it’s only through knowledge that greater things can
be achieved — to design your own circuits using op-amps,
you need to know what makes them tick.
An op-amp can be considered to be a general-purpose amplifier
with an extremely high gain. By itself (that is, with no
components connected to it) it will have a gain of many thousands.
Typical figures for the 741, for example, give a gain of
200,000 at zero frequency, although this varies considerably
from device to device. Now, nobody’s suggesting that this
sort of gain is particularly useful in itself — can you think of
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