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BELL SYSTEM TECHNICAL JOURNAL 



it from the circuit and take it apart. All of the circuit elements may 



be reached from the back of the cabinet without disturbing anything 



else, and on several occasions this arrangement has proved of great 



value. 



Power Supply for Amplifier 



Three sets of storage batteries are required for an amplifier. The 

 filaments are heated by a 6 V. 500 AH storage battery. The plate 

 voltage for the first three stages is supplied by a 250 volt 1 AH storage 



Fig. 5. 



battery while the plate voltage for the last stage is supplied by a 

 275 V. 4 AH storage battery. These batteries are in the general 

 battery room of each cable station and are handled by ordinary 

 methods, the only special precautions necessary being the shielding 



