Marked on plate: "Jefferson No. 280 / Radio Tube Charger / [directions] / Jefferson Electric Mfg. Co. / Chicago, USA"; on unit: "110 volts 50-133 cycles." A radio tube filament activator for thorium ...
Click to open image viewer. CC0 Usage Conditions ApplyClick for more information. IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage ...
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