Triode_Clark

This tube was an external control device, somewhat similar to the Moorhead Solenoid tube. The filament was a small loop of tungsten that was positioned in the vertical plane of the large hoop that served as a plate. Just outside the plate was a spiral of wire that served as the control element. Since the control winding was not positioned between the filament and rthe plate, this structure avoided the de Forest triode patent. One end of the control element is tied to the normal grid pin in the base and the other end to the metal shell. The glass bulb was etched "Geo C. Clark" and "Clark" was stamped on the top of the plate hoop. Two other tubes were designed by Clark, similar to the first tube. These both had round plates (with the Clarrk name on the back of these). The grid leads of these were connected to the base shell. The bases were made by the Shaw Insulator Company. No electrical data is known, and no informatiomn concerning the success of the tubes has been located.