Optical And Electrical Functions - ATN PVS7-HPT User Manual

1-9 OPTICAL AND ELECTRICAL FuNCTIONS

The optical functions include an objective lens, image intensifier, a
collimator lens and two eyepieces. The objective lens collects light
reflected from the night scene by the moon, stars or night sky and
inverts the image and focuses that image on the image intensifier.
The electrical functions include the following.
A. Power Source. The electronic circuit is powered by replaceable
batteries - either a 3.0 Volt lithium battery (BA-5567/U) or two AA
1.5 Volt alkaline batteries (BA-3O5S/U).
B. Electrical Principles. Power from the batteries is supplied to
the components through the RESET/OFF-ON-IR/PULL switch as
follows:
RESET/OFF Position. With the switch in the OFF position, the cir-
cuit is not energized either to the image intensifier or the IR illumi-
nator. Also, turn the switch to this position to reset after automatic
shutoff or high light cutoff.
ON Position. Power is drawn from the battery compartment to ener-
gize the goggle. When the voltage drops to 2.4 VDC, a low battery
indicator at the right eyepiece blinks indicating approximately 30
minutes of operating time.
IR/PULL Position. Power is drawn from the battery compartment to
energize the goggle and IR light source and a steady red indicator
light in the left eyepiece. The IR is momentarily turned on by turning
the switch past ON without pulling the knob.
C. Automatic Shutoff. When the goggle is removed from the head
mount or helmet mount while in operation, they will automatically
shut off. This prevents enemy detection of the green glow of the
image intensifier. To turn the goggle back on, turn the switch to RE-
SET/OFF and then to ON again.
D. High Light Cutoff. The goggle will automatically shut off after
70 (±30) seconds of operation in daylight or bright room light. In-
dividual bright lights (headlights, flashlights or other concentrated
light sources) will not actuate the high light cutoff function unless
focused directly on the high light detector located on the front of the
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