204461 ⎘
Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps; Main electrodes; Solid thermionic cathodes; Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment Insulating layer or body located between heater and emissive material
Feedthrough device including a gas discharge tube
#2Indirectly heated electrode for gas discharge tube, gas discharge tube using said indirectly heated electrode, and lighting device for said gas discharge tube
#3Multi-apertured conduction heater