3B SCIENTIFIC PHYSICS U8482230 Instructions D'utilisation page 5

3B SCIENTIFIC ® PHYSICS
Franck-Hertz Tube with Ne Filling on Base
1000912 / U8482230
Instruction sheet
04/12 ALF
1. Safety instructions
•
Do not subject the tube to any mechanical stress.
Do not put kinks in any connecting leads. There is
always a risk that glass can break and cause in-
jury.
2. Description
The Franck-Hertz tube is a tetrode with an indirectly
heated barium oxide cathode K, a mesh-type control
grid G, a mesh-type anode A, and a collector electrode
E (see Fig. 1). The electrodes are in a plane-parallel
configuration. The distance between the control grid
and the anode grid is about 5 mm, and the distances
between the cathode and the control grid and between
the anode and the collector electrode are both about 2
mm. The tube is supplied already filled with neon gas
at a pressure chosen to give an optimum characteristic
curve, which is in the region of several hPa.
The connecting sockets for the heater, control grid
and anode grid voltages are on the base of the in-
strument. The collector current is taken off through
the BNC socket at the top end of the screening cylin-
der. An internal 10 kΩ limiting resistor is perma-
nently built in between the connector sockets for the
1
1 BNC connector
2 Screening cylinder with obser-
vation window
3 Franck-Hertz tube
4 Base with connector sockets