AEG Coolidge Therapy Tube












                   Early Coolidge Therapy Tube, 32” (80 cms) long, strongly discolored, dating probably to the late 2nd decade, 20thCentury, bearing the AEG mark, Type II, No.3007, and the inscription “Fürstenau Coolidge Röhre, Veifa Werke, Frankfurt A/M”.


                   Concentric spiral filament “hot cathode” in a molybdenum cylinder, with a two-prong external connection.


                   Round tungsten target embedded in a lightweight copper anode.


                   Unknown technical specifications.





Before the U.S.A. entered WW1, AEG had obtained the privilege of manufacturing Coolidge tubes, and they had them made by Veifa. But the patent for using tungsten anodes belonged to Siemens & Halske. So an agreement was concluded in which each partner granted the other the use of both patents, and in which AEG reserved to itself the right to manufacture certain definite quantities of tubes for Siemens & Halske.

                                    Georg Siemens:”History of the House of Siemens”, 1957,  Karl Alber, Vol II, p.80)


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