3B Scientific Teltron Perrin Tube D - Manual

3B SCIENTIFIC® PHYSICS
1
Perrin Tube D 1000650
Instruction sheet
12/12 ALF
2 3 5 6
-
1 4 7
1 4mm sockets connected to
cathode filament and heating
2 Heater filament
3 4mm plug for connecting
anode
4 Boss
5 Fluorescent screen
6 Faraday cage
7 4mm plug connected to
Faraday cage
1. Safety instructions
Hot cathode tubes are thin-walled, highly
evacuated glass tubes. Treat them carefully as
there is a risk of implosion.
• Do not subject the tube to mechanical
stresses.
• Do not subject the connection leads to any
tension.
• The tube may only be used with tube holder D
(1008507).
If voltage or current is too high or the cathode is
at the wrong temperature, it can lead to the tube
becoming destroyed.
• Do not exceed the stated operating parameters.
• Only change circuit with power supply equip-
ment switched off.
• Only exchange tubes with power supply
equipment switched off.
When the tube is in operation, the stock of the
tube may get hot.
• If necessary, allow the tube to cool before
dismantling.
The compliance with the EC directive on elec-
tromagnetic compatibility is only guaranteed
when using the recommended power supplies.
2. Description
The Perrin tube serves to demonstrate the negative
polarity of electrons and to estimate the specific
electron charge e/m by magnetic deflection into a
Faraday cage, which is connected to an electro-
scope. It is also possible to investigate the deflec-
tion of electrons in two perpendicular magnetic
alternating fields and to demonstrate the effects, for
example by generating Lissajous figures.
The Perrin tube is a highly evacuated tube with
an electron gun, consisting of a pure tungsten
heater filament and a cylindrical anode contained
in a clear glass bulb, partly coated with a fluores-
cent screen. The electrons emitted by the elec-
tron gun form a narrow circular beam that can be
seen as a spot on the fluorescent screen. A glass
tube with a Faraday cage is set on the glass bulb
at about 45° to the undeflected beam.