Lesson 4/Learning Event 2
FIGURE 34. DEMONSTRATION OF FUSE OPERATION.
A common method of protection is to use a fuse in the lighting circuit. Whenever there is an
excessive current through the lighting circuit, the fuse will burn out and open the circuit. The short
circuit should be removed before the fuse is replaced. Disadvantages of using a fuse are that the
circuit must be traced to locate the trouble and that a burned-out fuse must be replaced. However,
it provides much cheaper protection to the system.
Blackout lighting is a requirement for certain combat operations. One purpose of blackout lighting is
to provide the vehicle operator with sufficient light to operate the vehicle in total darkness.
Another is to provide minimum lighting to show vehicle position to a leading or trailing vehicle
when the illumination must be restricted to a level not visible to a distant enemy.
The blackout driving light provides a white light of 25 to 50 candlepower at a distance of 10 feet
directly in front of the lamp. The lamp is shielded so that the top of the light beam is directed not
less than 2 degrees below the horizon. The beam distribution on a level road at 100 feet from the
lamp is 30 feet wide on a properly designed light.