926 



Voltaic Electricity. Section 4: Ohm's, KirchhoH's and Joule's Laws. 



No. 62 021 



62 021. 1 :. 3. 



62 023. 1 : 5. 



62 026. 1 : 8. 



02.021. Wheatstone Bridge after Weinhold, Figure, with 16 plugs (W. D. Fig. 517 [490]), * <> 

 with ratio arms: 10; 100; 100; 10; and comparison rheostat: 1; 2; 3; 4; 10; 20; 30; 40; 



100; 200; 300; 400 ohms 10. 0. n 



62.022. - - idem, with 20 plugs, with the same ratio arms and with comparison rheostat : 



0.1; 0.2; 0.3; 0.4; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400 ohms |12. 0.0 



;:.'. 023. Universal Pattern Wheatstone Bridge after Kohlrausch, Figure, with 5 com- 

 parison resistances: 0.1, 1, 10, 100 and 1000 ohms; very practical for rapid measure- 

 ments on wire resistances and electrolytic resistances 7. 10.0 



The resistances are read direct (without table) on a scale. In conjunction with a suitable galvano- 

 meter, e. g. No. 61,297 or 61,360, the apparatus serves for resistance measurements of from 0.05 to 20.000 

 ohms of solid conductors. By using alternating currents, generated by a small induction coil on the appa- 

 ratus, and a telephone instead of the galvanometer, it is possible to determine resistances of electrolytes, 

 the internal resistances of cells, also the contact resistances of earth plates of lightning anvstrrs. 



tii'.OiM. Box Telephone for above, for determining the resistance of electrolytes, with coil 



wound to suit 0. l. r >. 



02.025. Kohlrausch Bridge, without induction coil, otherwise as No. 62,023; range 0.05 to 

 20,000 ohms; can only be used for wire resistances by employing a suitable galvano- 

 meter, e. g., No. 61,297 or 61,360 '....' G. 0. 



2.o2G. Portable Resistance Testing Set, Figure, comprising Universal Mridge No. 62,023, 

 tialvanometer No. 61,297, Telephone No. 62,024 and 3 Dry Cells, the whole in a solid 

 lock-up oak carrying case, with handle 15. 15. 



62.027. --idem, but with Galvanometer No. 61,360, which is independent of external 



magnetic influences and requires no special adjustment 13. .V <l 



liL'.OL'x. Wheatstone-Kirchhoff Bridge without comparison resistances. Figure, with 

 stretched wire 1 m long. The resistance of the measuring wire can be trebled by in- 

 serting wires of the same material, stretched in the open, at both ends. The Bridge 

 has a well-guided slider with sliding contact which can be raised up, and an accurately 

 divided millimetre rule 8. 10.0 



62.029. Second Slider with the slide wire, for calibrating the measuring wire and enabling the 

 bridge to be used as a du Bois-Keymond current compensator or as a Thomson Double 

 Bridge ' 1. 10. o 



Cl. 2001, 5826, 

 S251. 



