Types Of Circuits; Series; Parallel - Craftsman 28906 Professional Shop Manual

ELECTRICAL
SYSTEM
7. How the system is wired together
The Rules: All circuits have some basic rules that
must be followed:
7a. All circuits must have at least one voltage
source. It could be a battery, an altenator
or both.
7b. All circuits must have a load. A circuit with-
out a load is the same as shorting out the
power source. Typical loads could be:
• lights
• a motor
• a solenoid
7c. All circuits must have a complete path
back to the voltage source. This is also
known as having continuity.
NOTE: On outdoor power equipment, the frame
of the machine is frequently used as the return
path to the battery. This is referred to as ground-
ing the machine. Any point on the frame should
be the same as the negative post of the battery
(Electrically) unless there is a bad connection
between the battery and the frame or between
the frame and the component or cable that is
assumed to be grounded to it.
7d. Most circuits have additional components
like switches and fuses.
Types of circuits
There are three ways a circuit can be wired:
• Series
• Parallel
• Series/parallel
Series
• Series circuits are wired so that the current has
only one path to follow. If one component in the
system fails, the circuit will be broken and whole
system will not work. See Figure 7.28.
L--
T Battery
Lamp (
Figure 7.28
Parallel
Parallel circuits are wired so that current has
multiple paths to follow. If a component in one of
the parallel paths fails, the rest of the circuit will
keep working. See Figure 7.29.
Lamp
m
Battery
Lamp
Lamp
Figure 7.29
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