N<>. lil 489. 



Glow Light Oscillographs. 



897 



61488. 1:10. 



61486 and 61487. 1 : 12. 



61 489 A. 



61 489 B. 



Demonstration and Graphic Reproduction 

 of Current Curves. 



<; 1.489. Glow Light Oscillograph Tube, Figure, after Gehrcke-Buhmer, for demonstrations 



and investigations, comprising oscillograph tube and stand 2. 10. 



Two axially arranged electrode wires are enclosed in an evacuated tube divided by an insulating 

 partition. The predominating cathode is covered over by a bluish glow at intervals when the current flows 

 through, this glow being proportional to the momentary current. The curve shape is rendered visible by 

 the aid of a rotating mirror and can be photographed when a certain rotational velocity is imparted to the 

 mirror. The velocity of the mirror can easily be made to suit the current-frequency predominating. 

 The tube can be used in a horizontal position for cinematographic photos. 



Pig. 61,489 A shows a photograph of an A. C. curve, and Fig. 61,4898 that of a condenser discharge. 

 If desired, and at an increased price, tubes can be supplied of quartz or Uviol glass. 



Cl. 3524, 5820, G009, 

 3540, 3541. 



