3B SCIENTIFIC PHYSICS U207001-230 Manual De Instrucciones página 8

6. Set-up

Set up Millikan's oil drop apparatus on a level
surface.

Turn the vertical adjustment knob clockwise as
far as it will go (see Fig. 2).

Move the measuring microscope to the end of
the stand rod on the base unit and secure it in
place by means of the knurled screw at the
bottom.

Use the focussing equipment to move the
measuring microscope forward as far as it will
go and roughly align it in the observation
window in the experiment chamber with the
help of the vertical adjustment knob.

Open the cover of the experiment chamber,
place the spirit level on the uppermost plate of
the plate capacitor and adjust the apparatus to
its optimum horizontal alignment with the help
of the adjustable feet.

Insert the adjustment in the top plate of the
plate capacitor and focus the microscope on
the needle (see Fig. 3). Select a suitable light
intensity and re-adjust the height of the
measuring microscope by means of the vertical
adjustment knob.

Remove the needle and close the experiment
chamber.

Fill the oil atomiser to about halfway with the oil
for Millikan's apparatus and carefully slot it into
the hole in the experiment chamber.

Connect the rubber bulb to the oil atomiser by
means of hose.
Fig. 2 Experiment chamber:
1 Cover,
2 Hole for oil atomiser,
3 Top capacitor plate,
4 Observation window,
5 Vertical adjustment knob for head of microscope,
6 Stand rod for measuring microscope
Fig. 3 View through the measuring microscope with the
adjustment needle in focus
7. Operation
7.1 Starting the display and control unit

Connect Millikan's apparatus to the mains via
its plug-in power supply.
The display and control unit will be ready to use
as soon as Millikan's apparatus has been
connected up via the plug-in supply.

Click the "Select" button ("Wählen") to access
the language menu.

Select the required language by pressing the
corresponding button and then click "Enter" to
confirm. This automatically returns you to the
main menu.

Click the "Next" button in the main menu to
access the measurement menu.
7.2 Optimisation of light intensity

Look through
measurement cell (the space between the
capacitor plates) and set up a suitable light
intensity. Adjust the light intensity during the
measurement as needed.
7.3 Production, selection and observation of
charged oil droplets

Give a single hard squeeze on the rubber
bulb to produce some oil drops and spray
them into the measurement cell.

Wait till suitable oil droplets appear in the cell.
This may take a few seconds.

Select one of the oil droplets you can see
descending slowly (about 0.025 – 0.1 mm/s).

Adjust the focus of the microscope if
necessary.
4
the microscope at the