THE CA THODE RA Y OSCILLOGRAPH 



13 



film; and third, tubes with a hot cathode, with a relatively low oper- 

 ating voltage. 



Of this last type is the Western Electric No. 224 Cathode Ray Oscil- 

 lograph. Since this is the tube with which I have had more direct 



Fig. 18 — Norinder, 1930 — group of oscillographs.'* 



contact I wish to discuss some problems of its development and op- 

 eration. 



The design of the tube shown in Fig. 19 is now fairly familiar,* and 



i« Norinder, H., Zeits. f. Phys., 63, p. 672, 1930. 



* Since the paper was read the tube has been altered in certain respects. The 

 glass enclosure for the filament has been replaced by one of metal, and the anode 

 and deflector plates are supported on machined insulating blocks. These changes 

 make the structure more rugged and insure more nearly perfect alignrnent of the 

 parts. The end of the bulb has been changed so as to present a cylindrical surface 

 instead of a spherical one, thus permitting more intimate contact between the flu- 

 orescent screen and a photographic film when contact photographs are made. 



