ELEC 242 Lab
Introduction
In the last two labs we studied the transducers we will be using
in our final project.
Now we need circuits to
process
the signals produced by the input transducers and deliver them
to the output transducers.
Because the power required to drive the output devices
(motor and LED) is greater than that produced by the inputs
(photodetectors),
these circuits must also provide
gain,
i.e. boost the applied voltage, current, or both.
Such circuits are called
active
circuits
(as opposed to
passive
circuits which contain
only resistors, capacitors,
and inductors), and the devices that do the boosting are called
active devices.
Our first active device is the
transistor,
which delivers more current to its
load
(connected to the collector or emitter)
that it receives from its input
(connected to the base).
In fact the additional
current
comes from an external power supply,
so no laws of physics are being violated.