Page 171 - Concise Encyclopedia of Robotics

Integrated Circuit
In digital electronics, a circuit that continuously takes the integral
of an input wave is called an integrator. An example of the operation
of an integrator is shown in the graph of Fig. 2. The input is a sine
wave. The output is, mathematically, a negative-cosine wave, but it ap-
pears as a sine wave that has been shifted by 90°, or one-fourth of a
cycle. Compare DERIVATIVE.
INTEGRATED CIRCUIT
An integrated circuit (IC) is an electronic device containing many diodes,
transistors, resistors, and/or capacitors fabricated onto a wafer, or chip, of
semiconductor material. The chip is enclosed in a small package with
pins for connection to external components. Integrated circuits are used
extensively in robots and their controllers.
Assets and limitations
Integrated-circuit devices and systems are far more compact than equiva-
lent circuits made from discrete components. More complex circuits can
be built, and kept down to a reasonable size, using ICs as compared with
discrete components. Thus, for example, there are notebook computers
with capabilities more advanced than early computers, which took up
entire rooms.
In an IC, the interconnections among components are physically tiny,
making high switching speeds possible. Electric currents travel fast, but
not instantaneously. The faster the charge carriers move from one com-
ponent to another, the more operations can be performed per unit time,
and the less time is required for complex operations.
Integrated circuits consume less power than equivalent discrete-
component circuits. This is important if batteries are used. Because ICs
draw so little current, they produce less heat than their discrete-component
equivalents. This results in better efficiency, and minimizes problems
that plague equipment that gets hot with use, such as frequency drift and
generation of internal noise.
Systems using ICs fail less often, per component-hour of use, than
systems that make use of discrete components. This is mainly because
all interconnections are sealed within an IC case, preventing corrosion
or the intrusion of dust. The reduced failure rate translates into less
downtime.
Integrated-circuit technology lowers service costs, because repair pro-
cedures are simple when failures occur. Many systems use sockets for ICs,
and replacement is simply a matter of finding the faulty IC, unplugging
it, and plugging in a new one. Special desoldering equipment is used for
servicing circuit boards that have ICs soldered directly to the foil.

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