No. 61 504. 



Oscillographs, Braun Tubes. 



899 



61 503 a. 1:8. 



61,496. Arrangement on the mirror for alternating charges and discharges of Condensers, for d. 

 observing the charge and discharge curves, Figure j 1. 15. 



61,497. Falling Slide for cinematographic photos. Price according to size of plates 



3. 0. to 



61,499. Cathode Ray Tube after F. Braun, Figure 



The mode of action of this vacuum tube is based on the fact that a cone of cathode rays supplied by 

 an influence machine or a rapidly working spark coil (the rays being restricted by a narrow diaphragm) 

 produces on the glow screen, which is coated with phosphorescent paint, a spot which is as small and bright 

 as possible, the behaviour of this spot being observed through the glass and mica. 



If a small magnetizing coil, the axis of which is placed fairly vertical to the tube, is slipped along the 

 tube, and a current allowed to traverse the latter, the cathode rays are deflected. If in addition an A. C. 

 is used, the spot of light is set into synchronous vibrations. If now a rotating mirror is placed opposite the 

 tube, the light spot is dissolved for the purposes of the curve. Ample means are therefore available for 

 studying the rapid variations of a magnetic field as well as the secular course of such fields. The current 

 curves of A. C. generating stations are adapted for such observations, as well as the curves of the 

 primary an secondary circuits of an induction coil. For suitable mirrors see Nos. 61,490 61,494. 



The rotation of the luminous point in magnetic rotating field is specially adapted for demonstration 

 purposes (of. List Nos. 61,503 and 61, 503 a). 



61.500. -- idem, larger, Figure, 1m long, with screen 130 mm diameter . 



61.501. -- idem, after Braun-Wehnelt, Figure, for electrostatic deflections 



61,502. Two Coils on Stand, Figure, one arranged to rotate 



The luminous point describes Lissajous's and similar curves if alternating current is conducted 

 through two coils placed on the diaphragm of the Braun tube. By rotating one of the magnetizing coils, 

 and thereby altering the angle enclosed by the two coils, the various figures are obtained. 



If current from a central station is employed, a glow lamp resistance must be placed in series (see 

 N.I. 61,504). 



(!!,. ")().5. Magnetizing Ring for Two-phase Current, fitting the stand of preceding apparatus. 

 Price without stand . . 



61,50.'! a. - idem, for .'{-phase current, Figure, without the retort holder illustrated 

 and without stand . 



c.l.r.o.'l l>. Stand for Xos. 6 1.503 and 61,503 a 



('.1,504. Glow Lamp Resistance 



Tiiis resistance consists of 4 glow lamp holders each with two current terminals, mounted on a slate 

 slab. It is used when apparatus Nos. 61,502 60,503a are to be worked connected direct to a network. 



6. 0. 



1. 0. 



3. 0.0 

 1. 15. 

 1. 10. 



1. 16. 



1. 16. 



0. (i. 



1. 4. 



Cl. 2740. 



