3B Scientific Teltron Perrin Tube S - Manual

3B SCIENTIFIC® PHYSICS
1
Perrin Tube S 1000616
Instruction sheet
12/12 ALF
1 2 3 4 5 6 7 8 9
1 Guide pin
2 Connection pins
3 Heater and cathode
4 Cathode can
5 Anode
6 Deflector plates
7 Fluorescent screen
8 Faraday cage
9 4 mm 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 only may be used with tube holder S
(1014525).
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 use safety experiment leads for con-
necting circuits.
• 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 deflec-
tion into a Faraday cage, which is connected to
an electroscope. It is also possible to investigate
the deflection of electrons in two perpendicular
magnetic alternating fields or by collinear elec-
tric and magnetic alternating fields (Lissajous
figures).
The Perrin Tube is a highly evacuated tube with
an electron gun, consisting of an oxide cathode
heated indirectly via a heating coil, a cylindrical
anode and pair of deflector plates contained in a
clear glass bulb, partly coated with a fluorescent
screen. The electrons emitted by the electron
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.