Copyright Goodheart-Willcox Co., Inc.
Chapter 11 Electrical Engineering 243
Motors
You learned previously how generators convert
mechanical energy into electrical energy. Motors
work in the opposite way, changing electrical
energy into mechanical energy. Picture an electro-
magnet between two permanent magnets. The
electromagnet spins until its north pole is lined up
with the south pole of the permanent magnet and
its south pole is lined up with the north pole of the
permanent magnet. By this time, the polarity of the
electromagnet has reversed, causing it to be repelled
from the permanent magnet and attracted to the
other side. In this way, the magnet keeps rotating.
Component Platforms
To use the components previously described,
they must be linked together on a platform. The
most common type of platform used to create
circuits is a circuit board. To experiment before
soldering the components together, solderless
breadboards can be used.
Circuit Boards
Circuit boards are commonly known as PCBs
(printed circuit boards). A rigid piece of insula-
tion (typically fi berglass) is used as a platform for
circuitry. Thin copper tracks are laid on the insu-
lation, and electronic components are soldered to
the track. See Figure 11-27.
Solderless Breadboards
Solderless breadboards are ideal for experi-
mentation and testing circuits before they are
constructed. Components and leads can easily
be moved from one place to another because
no soldering is required to make connections.
See Figure 11-28.
See Workbook Activity 11-12 to learn how to
build an electrical circuit.
Figure 11-27. 
Circuit boards contain
copper tracks to which
electronic components are
soldered.
Trombax/Shutterstock.com
Goodheart-Willcox Publisher
Figure 11-28. 
Solderless breadboards can be used to experiment with
circuits before soldering to make connections.