CH. Ill] 



ARC LAMPS WITH SMALL CURRENTS 



these precautions are taken, it will be very simple to connect up 

 the lamp correctly at any time. 



"Polarized attachment and extension plugs" are made (fig. 48A, 

 4pA). These can only be put together one way. They are very 

 convenient for direct current connections; they are also equally 

 adapted for alternating current. 



FIG. 49. SEPARABLE ATTACHMENT PLUGS. 

 (Cuts loaned by II. Ilubbell, Inc.}. 



A Polarized, separable plug for a lamp socket. The metal prongs are in 

 planes at right angles and hence can be inserted in only one way, thus avoiding 

 change of polarity with direct current. 



B Non-polarized attachment plug. The connection can be made either 

 way around as the prongs are in the same plane. 



FIG. 50. SEPARABLE EXTENSION CONNECTOR. 

 (Cut loaned by II. Ilubbell, Inc.). 



This is to enable one to extend the line by joining separate cables. These 

 extension connectors can be had with polarized or non-polarized prongs to the 

 cap. 



131. Carbons for small currents; feeding the carbons. For 



the small currents used with the house circuit, the carbons should 

 be small. For alternating current of five to six amperes, 8 mm. 

 carbons answer well. For three to four amperes the carbons 

 should not be over 6 mm. in diameter. 



