GU8

Va<22kV piv. Ia<4A average dc. Tube designed for telephony as a half wave mercury rectifier. Tube mounted verticaly, 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 its working temperature and that the condensation temperature may be within the rated limits before the anode voltage is supplied. For a new tube, or when has been stored or transported, the filament must be run at least 30 minutes at normal filament voltage before the anode voltage is applied. The two pins of the filament are one incgh long and set one quarter of an inch apart.