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7.3 Transmitted-light stand EB,
bright field
A complete Illumination System including a
6 V / 2 0 W halogen bulb, a regulating trans-
formier and a thermal fuse, is built into the
transmitted-light stand EB (fig. 1). The spe-
cially-designed collector System permits op-
timal useof the light.This stand isparticularly
useful for photomicrography in transmitted-
light bright field.
Further details about the Operation of this
stand and in particular about the use of the
interchangeable collector lenses and the
swing-in frosted f ilter are given in the Instruc-
tion booklet M2 295.
7.4 Transmitted-light stand,
b r i g h t / d a r k field
The transmitted-light stand for bright and dark
field (fig. 3) enables observations and pho-
tography to be carried out in either bright
field or dark field.
In the dark field technique, no light passes
directly through the specimen into the ob-
jektive (fig. 2); light reflectedatthe interfaces
of components with differing refractive in-
dices travels into the objective, however, so
that a bright image on a dark background is
seen and the contrast of weakly-coloured or
transparent specimens can be increased.
The built-in 12 V / 1 0 0 W halogen bulb pro-
duces high light intensity at a colour tempe-
rature ideal for photomicrography.
It is connected to the 12 V regulating trans-
formier, which simultaneously controls the
fan.
The changeover from bright to dark field and
back is carried out with the lever at the rear
ofthebase.
Further details on the use of this stand are
to be found in the Instruction booklet M2 280.
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