VT191_GPO

Tube designed for telephony and as a half wave mercury rectifier. Tube mounted vertically, base down so as to allow cooling of the base. This situation must be the same during storage so that the filament and anode cannot be contaminated by the mercury. In operation, there must be a time delay after switching on the filament in order that the filament may attain its working temperature and that the condensation temperature may be within the rated limits before the anode voiltage is supplied. For a new tube, or when the tube has been stored or transported, the filament must be run for at least 30 minutes at normal filament voltage before the anode voltage is applied. The two pins of the filament are one inch long and set one quarter of an inch apart.