3B Scientific Teltron Critical Potentials Tube S with He-Filling - Manual (Page 2)

2
3. Contents
1 Critical potentials tube S with He filling
1 Battery unit (battery not included)
1 Shielding
1 Manual
4. Technical data
Gas filling: Helium
Filament voltage: U
F
≤ 7 V DC
Anode voltage: U
A
≤ 60 V
Anode current: I
A
≤ 10 mA
Collector voltage: U
R
= 1,5 V
Collector current: I
R
≤ 200 pA
Glass bulb: 130 mm diam. approx
Length of tube: 260 mm approx.
5. Additionally required
For operating the tube:
1 Tube holder S
1014525
1 Control Unit for Critical Potential Tubes
(115 V or 230 V)
1000633 / 1008506
1 DC-Power Supply, 0–20 V
(115 V or 230 V)
1003311 / 1003312
or
1 Power Supply Unit for Franck-Hertz Experiment
(115 V or 230 V)
1012819 / 1012818
For making measurements:
1 Analogue Oscilloscope 2x30 MHz 1002727
2 HF Patch Cords, BNC/4 mm Plug
1002748
or
1 3B NETlog
TM
(115 V or 230 V) 1000539 / 1000540
1 3B NETlab TM 1000544
1 Battery AA 1.5 V
1 Set of 15 Safety Experiment Leads 1002843
6. Operation
6.1 Setting up the tube in the tube holder
• The tube should not be mounted or removed
unless all power supplies are disconnected.
• Press tube gently into the stock of the holder
and push until the pins are fully inserted.
Take note of the unique position of the guide
pin.
6.2 Removing the tube from the tube holder
• Allow the tube to cool before dismantling.
• To remove the tube, apply pressure on the
guide pin until the pins loosen, then pull out
the tube.
7. Example experiment
Determine the critical potentials of a helium
atom
7.1 General notes
The experiment set-up with the critical potential
tube is highly sensitive to sources of electro-
magnetic interference. (computers, fluorescent
lights).
• Select a location for the experiment where
electromagnetic interference can be
avoided.
7.2 Experiment set-up with the control unit
for critical potential tubes
• Insert the tube into the tube holder.
Provision of heater voltage V
F
:
• Connect the sockets F3 of the tube holder to
the positive terminal of the DC power supply
and F4 to the negative terminal. (see Fig. 1)
Provision of accelerating voltage V
A
:
• Connect socket C5 of the tube holder to the
negative terminal of the output V
A
on the
control unit and to the negative terminal of
the DC power supply.
• Connect socket A1 to the positive terminal of
the output V
A
on the control unit.
Provision of collector voltage V
R
:
• The positive pole of the output V
A
should be
connected to the negative pole of the 1.5-V
battery.
• Connect the positive terminal of the 1.5 V
battery to an earth socket on the control unit.
• Put the shielding over the tube and slot it into
the groove on the tube holder so that the tube
is completely enclosed by shielding. Then
connect the control unit by means of the
ground socket.
• Connect the lead from the collector ring to
the BNC input socket of the control unit.