Olympus BH-P Instruction Manual - Page 11
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V.
OPERATION
1. Electric System
1) Adjustment of Light Intensity
The rninimum voltage required for the light source can be adjusted w i t h the rheostat
trimmer screw at the bottorri of the microscope base in accordance w i t h the line voltage
and frequency.
A
silicon controlled rectifier (SCR) is provided lor output voltage
control. The
SCR
has the following advantages over conventional rheostat cor-itrols.
@
Extremely fine adjustment of light intensity can be easily achieved
@
Flickering of the bulb filament is elirninated and light intensity is stabilized.
@
Increased life expectancy o f the bulb.
2)
Adjustment of Minimum Line Voltage
@
Ascertain that the voltage selector switch is set to conform w i t h the local mains
voltage. (This switch can be turned w i t h a coin, and can be set to the following
voltages: 100V-110V-I 20V or 220V-240V.)
(3
Ascertain that the sliding control lever is positioned closest to you ( l o w voltage), and
then activate the main switch. The pilot lan-ip lights up.
@
If the bulb is dimnily lit, and the voltmeter indicates about I V , the secondary voltage
is correct, and you have only t o push the sliding control lever forward in order to
obtain optimum light intensity.
@
I f the bulb does not light or lights up brightly immediately after switching on, rotate
the rheostat trimmer screw gradually w ~ t h a coin, until the voltmeter indicates
about 1V.
3)
Light Source
The standard light source incorporates a 30W pre-centered tungsten filament bulb,
provided with a socket for positive contact, eliminating the problems of defective
contact and over-heating.
When used at the rated voltage 6V. the aver-age lrfe of the tungsten bulb LS30 is longer
than 200 hours. This is,.however, greatly reduced, if the bulb is used at higher voltage; for
instance, the bulb life is reduced to 1/50 at 8V. Therefore, it is advisable t o avoid
prolonged use at readings over 6V ( i n the red rorie).
I f the light source should be used at high voltage constantly, i t is reconirnended to usea
high intensity halogen bulb.
*
Do not switch the tungsten bulb on &ith the sliding control lever at high intensity posi-
tion (away from the user). I t reduces bulb life.