DOCTER DOCTER®nightvision 1x24 - Manual (Page 26)

observation device on a reasonable level in relation to the user’s requirements, the
choice of our image intensifiers is oriented on the MIL standard.
Tubes without aberrations are, for instance, used in medical engineering or for
astronomic observation. Although these image intensifiers have similar parameters,
their costs are many times over.
Signal-to-Noise (S/N) ratio
It describes the ratio between the image and noise of an image intensifier tube. In poor
light conditions, tubes with a very high S/N ratio show less disturbing image noise.
Automatic Brightness Control (ABC)
Control of the voltage at the image intensifier (between phosphor screen and micro-
channel plate) in dependence of the object’s radiance.
Luminous sensitivity
The value stated for the luminous sensitivity is a value that is used for sensors operating
in the visible wave length range. It is determined in µA/lm from the relationship between
the output current of the photo cathode and the incoming light flow of a standard
tungsten lamp (colour temperature: 2856 K).
Batteries
In cold weather, you should wear the device close to your body, as low temperatures
reduce battery power. If you do not use this device for a longer time, the battery should
be removed. Keep the battery at a cool and dry place.
The battery warning indicator starts at a residual battery voltage of 1.1V. Should voltage
drop below 0.9V, such voltage will no longer suffice to operate the night vision device.
As shown in the diagram below, the various battery types have different discharge
graphs. Hence, the duration of operation after the first lighting of the battery warning
LED heavily depends on the battery type.