The invention concerns a light source having an apparatus for measuring the brightness
of the illumination system of an optical viewing device, for example a microscope,
in which at least one light sensor (3a) for measuring the intensity
of the lamp (1) is arranged, for example, next to the optical waveguide
(2). That measurement can be passed on to the user (9), either acoustically
or visually, via an electronic unit (4) which compares the measurement to
a definable threshold value.
