Levenhuk MED 25 User manual

Levenhuk MED 25 Microscopes
User Manual

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1 Eyepiece 12 Condenser with lter holder
2Binocular/trinocular eyepiece head 13 Collector
3 Arm 14 Stage moving knob (right/left)
4Revolving nosepiece 15 Stage moving knob (back/forth)
5Objective 16 Illumination on/o button (not shown)
6Stage 17 Beam splitter (trinocular models only)
7Mechanical scale 18 Diopter adjustment ring
8Brightness adjustment knob 19 Binocular/trinocular head locking screw
9Aperture diaphragm adjustment rod 20 Third eyepiece tube (trinocular models only)
10 Coarse focusing knob 21 Tension adjusting ring
11 Fine focusing knob
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1
3
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Fig. 1a. Levenhuk MED 25B Fig. 1b. Levenhuk MED 25T, D25T, D25T LCD
Fig. 2a Levenhuk MED D25T
1Digital camera
2USB cable
3Installation CD
Fig. 2b Levenhuk MED D25T LCD
1Digital camera with LCD screen
2AC adapter
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21 10
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14 148 815 15
13 13
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General Information
Read the user manual carefully before you start working with a microscope. Levenhuk MED Series biological microscopes are
safe for health, life and property of the consumer and the environment when properly used, and meets the requirements of
international standards. These microscopes are designed for observing transparent objects in the transmitted light using the
bright eld method and the dark eld method. They perform well in clinical research and tests; teaching demonstrations;
bacterioscopy and cytology in medical and health establishments, laboratories, universities; and may be used for scientic
research in agriculture and microbiology.
Microscope assembly
• Unpack the microscope carefully and place it on a at surface.
• Remove the plastic bags and dustproof cover of the eyepiece head.
• Install the binocular or trinocular head and tighten the locking screw.
• Inspect all the items included in the kit and dene their purpose.
• Connect the power cord to the microscope and plug it in.
Microscope use: The bright-eld method
Please refer to the g. 1а (binocular model) and g. 1b (trinocular model).
• Turn on the power and the illumination will turn on. Set the brightness at approximately 70%. Place the specimen on the
stage. Make sure the clips hold the specimen rmly in place.
• Iris diaphragm should be adjusted in accordance with numerical aperture of a lens. The best practice is to make the iris
diaphragm slightly smaller than the aperture of the selected lens. Open or close the iris diaphragm using the adjustment
screws. If the adjustment screw is turned to the right, the iris diaphragm is fully open. Note: the diaphragm is not intended
for adjusting the brightness of the illumination. To adjust the brightness, use the brightness adjustment knob.
• Slide the lter holder, place the lter in it and then return the holder to its initial position.
• To change the objective magnication, turn the revolving nosepiece until it clicks.
• Make sure that the lens does not touch the sample when adjusting the focus: rotate the coarse focus knob until the
specimen is about 3.175mm (1/8") away from the lens.
• Looking into the eyepiece, slowly turn the coarse focusing knob until you can see the image of the observed specimen. Turn
the ne focusing knob to make the image clear. The ne focusing mechanism allows you to focus on the observed specimen
while using high magnications.
• When you use an oil immersion objective, the space between the specimen and the lens should be lled with immersion oil.
Raise the condenser to the upper position and put a drop of oil on the lens and on the cover glass of the specimen. Move the
revolving nosepiece back and forth to get rid of air bubbles in the oil. Then, x the objective lens in its working position.
Make sure that oil lls the entire space between the objective lens and the specimen. After use, wipe the lens dry.
• To adjust the position of the mechanical scale, turn the coarse focusing knob in a clockwise direction if you want to x the
position of the mechanical scale, or in a counterclockwise direction if you want to loosen it.
• To place the specimen in the eld of view, move the stage horizontally back and forth or left and right using the stage
moving knobs.
• Look through the right eyepiece with your right eye and adjust the image sharpness with the coarse and ne focusing knobs.
Then, look through the left eyepiece with your left eye and rotate the diopter adjustment ring to equalize the dierence
between your left and right eyes vision. Remember the setting for future use. Adjust the distance between the eyepiece
tubes of the binocular head so that the image merges into a single circle.
• Trinocular models: you can install the digital camera to the third eyepiece tube. Use the beam splitter to send the light to
the eyepieces or to the camera.
Dark eld condenser (oil)
Conguration and operating principle
Please refer to g 3. The device is designed for studying low-contrast objects that are not visible in the microscope when
observed in normal light conditions using the bright eld method. The dark eld method allows you to observe very bright and
transparent objects in scattered or reected light.
1
2
3
4
Fig. 3
1Spherical mirror and cardioid lens, glued together and
inserted into the frame
2Cylinder
3 Body
4Adjustment screws

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The dark eld condenser is a system of lenses inserted into the cylinder. The cylinder is placed inside the microscope body on
the moving ring. This ring is a centering device, which can be controlled with adjustment screws located on the outside of the
microscope body.
The light from the illuminator, passing through the dark eld condenser, is converted into a cone-shaped beam and directed at
the observed specimen. Almost all of the light passes through the lens and forms an image only by the light scattered by the
structure of the specimen. Therefore, in the eld of view of the eyepiece, the bright contrast areas of the specimen structure
are displayed on a dark background.
Assembly and using
• Install a dark eld condenser instead of the standard condenser of your microscope.
• Install the desired eyepiece and choose the objective with the lowest magnication.
• Put a drop of oil on the condenser lens; x the microscope slide on the stage. Note: It is recommended to use a coverslip
with a thickness of 0.8—1.2mm.
• Raise the dark eld condenser until the immersion oil meets the stage and then focus.
• If you see an o-center light spot, use the adjustment screws to bring it to the center of the eld of view.
• Note: The aperture of the objective lens used must be smaller than the aperture of the condenser.
Halogen bulb replacement
Unplug the microscope from a power source. Loosen the knurled screw on the underside of the microscope and open the panel
to gain access to the lamp. Make sure the lamp has cooled down and then remove it. Do not touch the new lamp with your
ngers; ngerprints or dirt will reduce the brightness and the lamp’s life. Use gloves to replace the lamp. If necessary, wipe the
lamp with a clean, soft cloth. Use a lamp of a suitable type. Insert the contacts into the slot vertically. Then, close the panel
and tighten the knurled screw nger tight.
Fuse replacement
Unplug the microscope from a power source. Open the fuse holder located on the back of the microscope body with a at head
screwdriver. Remove the old fuse and install a new one. Only use the appropriate types of fuses. Close the fuse holder.
Digital camera
Levenhuk MED D25T comes with a digital camera (g. 2a), Levenhuk MED D25T LCD comes with a digital camera with an LCD
screen (g. 2b). A digital camera is installed to the third eyepiece tube and enables observing specimens on the screen in
exquisite detail and true color, taking photos and videos, and saving the images for future reference.

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Specications
Product ID 73992 73993 73994 73995
Model MED 25B MED 25T MED D25T MED D25T LCD
Type biological/optical biological/optical, digital
Research method bright and dark eld bright and dark eld
Magnication 40—1000x 40—1000x
Interpupillary distance 55—75mm 55—75mm
Eyepiece head
binocular,
360° rotatable,
inclined at 30°
trinocular,
360° rotatable,
inclined at 30°
trinocular, 360° rotatable,
inclined at 30°
Optics material optical glass with an anti-fungal coating optical glass with an anti-fungal coating
Eyepiece tube diameter 23.2mm 23.2mm
Third vertical eyepiece tube — 23.2mm 23.2mm
Eyepieces WF10x/18mm (2pcs) WF10x/18mm (2pcs)
Eyepiece diopter adjustment ±5D ±5D
Objectives Plan: 4x, 10x, 40xs, 100xs (oil) Plan: 4x, 10x, 40xs, 100xs (oil)
Revolving nosepiece 4 objectives 4 objectives
Stage moving range 75/50mm 75/50mm
Stage double layer mechanical, 140x140mm,
with a mechanical scale
double layer mechanical, 140x140mm,
with a mechanical scale
Focus system
coaxial,
coarse (0.5mm) and ne (0.002mm),
with rack and pinion mechanism
coaxial,
coarse (0.5mm) and ne (0.002mm),
with rack and pinion mechanism
Condenser (bright eld) Abbe N.A. 1.25 iris diaphragm and
lter holder
Abbe N.A. 1.25 iris diaphragm and
lter holder
Condenser (dark eld) oil, N.A. 1.36—1.25, with dovetail mount oil, N.A. 1.36—1.25, with dovetail mount
Body metal metal
Illumination lower (halogen, 6V/20W)
with brightness adjustment
lower (halogen, 6V/20W)
with brightness adjustment
Collector Köhler illumination Köhler illumination
Filters blue, green, yellow blue, green, yellow
Vial of immersion oil + +
Fuse 2pcs 2pcs
Power supply 100—240V, via AC adapter 100—240V, via AC adapter
Digital camera — 5.1Mpx 5Mpx with
LCD screen
Camera connector — + +
Camera power supply — DC 5V,
via USB 2.0 cable
DC 12V/2A,
via AC adapter
Optional accessories (sold separately) eyepieces (D 23.2mm): 5х, 12.5х, 16x, 20x eyepieces (D 23.2mm): 5х, 12.5х, 16x, 20x
—digital camera —
Levenhuk reserves the right to modify or discontinue any product without prior notice.

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Care and maintenance
• Never, under any circumstances, look directly at the Sun, another bright source of light or at a laser through this device, as
this may cause PERMANENT RETINAL DAMAGE and may lead to BLINDNESS.
• Take necessary precautions when using the device with children or others who have not read or who do not fully understand these
instructions.
• After unpacking your microscope and before using it for the rst time check for integrity and durability of every component and
connection.
• Do not try to disassemble the device on your own for any reason. For repairs and cleaning of any kind, please contact your local
specialized service center.
• Protect the device from sudden impact and excessive mechanical force. Do not apply excessive pressure when adjusting focus. Do
not overtighten the locking screws.
• Do not touch the optical surfaces with your ngers. To clean the device exterior, use only special cleaning wipes and special optics
cleaning tools from Levenhuk. Do not use any corrosive or acetone-based uids to clean the optics.
• Abrasive particles, such as sand, should not be wiped o lenses, but instead blown o or brushed away with a soft brush.
• Do not use the device for lengthy periods of time, or leave it unattended in direct sunlight. Keep the device away from water and
high humidity.
• Be careful during your observations, always replace the dust cover after you are nished with observations to protect the device
from dust and stains.
• If you are not using your microscope for extended periods of time, store the objective lenses and eyepieces separately from the
microscope.
• Store the device in a dry, cool place away from hazardous acids and other chemicals, away from heaters, open re and other
sources of high temperatures.
• When using the microscope, try not to use it near ammable materials or substances (benzene, paper, cardboard, plastic, etc.), as
the base may heat up during use, and might become a re hazard.
• Always unplug the microscope from a power source before opening the base or changing the illumination lamp. Regardless of the
lamp type (halogen or incandescent), give it some time to cool down before trying to change it, and always change it to a lamp of
the same type.
• Always use the power supply with the proper voltage, i.e. indicated in the specications of your new microscope. Plugging the
instrument into a dierent power outlet may damage the electric circuitry of the microscope, burn out the lamp, or even cause a
short circuit.
• Seek medical advice immediately if a small part or a battery is swallowed.
Levenhuk International Lifetime Warranty
All Levenhuk telescopes, microscopes, binoculars and other optical products, except for accessories, carry a lifetime warranty against
defects in materials and workmanship. Lifetime warranty is a guarantee on the lifetime of the product on the market. All Levenhuk
accessories are warranted to be free of defects in materials and workmanship for six months from date of retail purchase. Levenhuk
will repair or replace such product or part thereof which, upon inspection by Levenhuk, is found to be defective in materials or
workmanship. As a condition to the obligation of Levenhuk to repair or replace such product, the product must be returned to Levenhuk
together with proof of purchase satisfactory to Levenhuk. This warranty does not cover consumable parts, such as bulbs (electrical,
LED, halogen, energy-saving and other types of lamps), batteries (rechargeable and non-rechargeable), electrical consumables etc. For
further details, please visit our web site: www.levenhuk.com/warranty
If warranty problems arise, or if you need assistance in using your product, contact the local Levenhuk branch.
Levenhuk, Inc. 924-D East 124th Ave. Tampa, FL 33612 USA
Levenhuk® is a registered trademark of Levenhuk, Inc.
© 2019—2020 Levenhuk, Inc. All rights reserved.
www.levenhuk.com
20200124
!
Caution! Please remember that mains voltage in most European countries is 220—240V. If you want to use your device
in a country with a dierent mains voltage standard, remember that use of a converter is absolutely necessary. The
microscope must be grounded. Make sure that the main voltage matches the voltage indicated on the microscope
body.