BASIC ELECTRONICS - OD1633 - LESSON 1/TASK 2
FIGURE 36.
GROUND USED AS A CONDUCTOR.
Sometimes an open can be located visually by a close inspection of the
circuit components. Defective components, such as burned out resistors, can
usually be discovered by this method.
Others, such as a break in a wire
covered by insulation or the melted element of an enclosed fuse, are not
visible to the eye. Under such conditions, the understanding of the effect
an open has on circuit conditions enables a technician to make use of test
equipment to locate the open component.
In figure 37 (on the following page), the series circuit consists of two
resistors and a fuse.
Notice the effects on circuit conditions when the
fuse opens.
Current ceases to flow; therefore, there is no longer a voltage drop across
the resistors. Each end of the open conducting path becomes an extension of
the battery terminals and the voltage felt across the open is equal to the
applied voltage (EA).
An open circuit has infinite resistance.
Infinity
represents a quantity so large it cannot be measured.
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