Operation of an Original Hanau Kleinen 'Künstlichen Höhensonne' (1:14)
video about the operation of an Original Hanau Kleinen Künstlichen Höhensonne
The Original Hanau 'Kleinen Künstlichen Höhensonne' (1929) was an early mercury
vapour arc discharge sunlamp that was ignited with the so-called tilt method. The
discharge tube contained an anode and a cathode, the latter in the form of a pool of
mercury, and was manually tilted until the mercury reached the anode. The mercury
now conducted the full short-circuit current, only limited by a serial ballast. When the
tube was tilted back slowly, the mercury would eventually disconnect from the anode,
causing a small arc discharge (a spark) at the place where the last contact occurred.
This discharge would locally cause some mercury to evaporate and the gas pressure
and the temperature within the tube would rise slightly. This caused an environment in
which a small arc discharge could develop, rising pressure and temperature any
further. After a short while and, if necessary, some repeated tilting forth and back, the
arc discharge would become continuous even when the tube was tilted back
completely and gas pressure and temperature would adjust themselves to the steady
state working conditions of the circuit.