DEVELOPMENTS IN COMMUNICATION MATERIALS 



253 



100,000 



80,000 



^ 60,000 



ffl 

 < 



ui 



S 

 a. 



UJ 



a 



i. 40,000 



20,000 



4 000 8,000 12,000 



B 



Fig. 16 — Permeability curves of soft iron and permalloy. 



16,000 



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o 



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 Q. 



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o 

 < 



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10 



100 1,000 



CYCLES PER SECOND 



10.000 



Fig. 17 — Showing improvement in quality of voice frequency amplifier due to permal- 

 loy core transformers. 



17 



