Hg Franck-Hertz tube

LD 555854
Hg Franck-Hertz tube
Hg Franck-Hertz tube

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For demonstrating the discontinuous release of energy by free electrons upon collision with mercury atoms, and for determining their excitation energy. The Franck-Hertz curve is plotted either point-by-point with indicating instruments or continuously by means of a recorder or CASSY.
Vacuum tube with indirectly heated cathode, emission control grid, anode grid, collector and a mercury drop which vapourizes when the tube is heated. Please note: the Franck-Hertz tube (555 854) can only be used in conjunction with the corresponding sockets (555 864/555 865). It is not possible to run it on the socket for the old Franck-Hertz tube (555 85, no longer available).

Technical data

  • Filament: 3.15 V/0.4 A
  • Grid voltages:
    Emission grid: 0 - 4 V DC
    Anode grid 0 - 40 V DC
  • Counter-voltage at collector: approx. 1.5 V DC
  • Socket: 8-pin socket
  • Mercury filling approx. 5 g
  • Excitation energy of the Hg atoms 4.9 eV
  • Operating temperature: approx. 200 °C
  • Dimensions: 10 cm x 2.8 cm diam.
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