2. Description
The Franck-Hertz control unit can be used to
conduct the Franck-Hertz experiment with
mercury vapour or with neon gas. It provides
all of the operating voltages required to conduct
the Franck-Hertz experiment, and contains a highly
sensitive DC amplifier to measure the current at
the collector electrode.
1. Accelerating voltage U
Options are a regulated DC voltage of 0 ... 80 V
(toggle switch: "Man") or a sawtooth voltage 0 ...
80 V
, 50/60 Hz (toggle switch: Ramp). At the oscil-
SS
loscope output U
/10, this voltage is divided by 10.
B
2. Heater voltage U
:
H
DC voltage 4 ... 12 V for the heater filament of the
indirectly heated oxide cathode.
3. Retarding voltage U
:
G
DC voltage of 1, 2 ... 10 V for reverse bias between
grid and collector electrode.
4. Control voltage:
DC voltage of 9 V for the control grid in the neon-
filled Franck-Hertz tube
5. DC amplifier:
The DC amplifier provides a voltage proportional to
the collector current, rated up to 10 mA. At the
lowest amplification 1 V of voltage measured corre-
4.1 Franck-Hertz tube with Hg filling
Additionally required:
1 Franck-Hertz tube filled with mercury plus furnace
1 Digital thermometer, 1 channel
1 Immersion sensor NiCr-Ni Type K
1 Analog oscilloscope, 2 x 35 MHz
1 HF lead, 1 m
2 HF leads, BNC / 4-mm plug
Safety leads for experiments
M
H
Fig. 1 Experiment set-up - Franck-Hertz tube filled with mercury
:
B
4. Examples of use
M
A
K
sponds to an electron current of 10 μA approx. and
at the highest amplification to an electron current
of 10 nA approx.
The apparatus U8482130-115 is for operation with
a mains voltage of 115 V (±10%), and the unit
U8482130-230 is for operation with a mains volt-
age of 230 V (±10%).
3. Technical data
Mains voltage:
Heater voltage:
Heater current:
Accelerating
voltage:
Retarding voltage:
Control voltage:
FH signal input:
Outputs:
Dimensions:
Weight:
U8482150-230 or U8482150-115, as required
U11817
U11854
U11175
U11255
U11257
A
H
K
2
See back of chassis
4 ... 12 V
180 ... 400 mA
0 ... 80 V,
1, 2 ...up to 10 V
9 V
BNC connector
4-mm safety sockets
160 x 132 x 210 mm
2.4 kg