420 THE BELL SYSTEM TECHNICAL JOURNAL, APRIL 1951 



reduction is realized for this type since the high tensile strength of tantalum 

 permits manufacture using very thin foil. From the measured stabihty of 

 the tantalum oxide fihn, and from the known immunity of tantalum to at- 

 tack by acid reagents, it is concluded that the life of a tantalum electrolytic 

 capacitor will be several times that of the corresponding aluminum electro- 

 lytic capacitor. Three capacitance ratings are in production for use in the 





lii 



^M-}SW 



Fig. 1 — Tantalum capacitors. Upper: Sintered type, 4 mf/60 volt polar; Lower: Foil 

 type, 1 mf/150 volt nonpolar. 



N-1 System: one of the sintered construction, 4 mf/60 volts polar; and two 

 of the foil construction, 1 mf/150 volts polar and 1 mf/150 volts non-polar. 

 Examples of these capacitors are illustrated in Fig. 1. 



The inductors employed in the Type N System are of several types. 

 Two toroidal type inductors, each wound over a small low cost molybdenum 

 permalloy dust core, are used in the voice frequency filters and in battery 

 supply leads. Individually mounted duo-lateral wound inductors find ap- 

 plication in interstage networks. Two duo-lateral type inductors wound on 

 a common molded phenolic core tube are used in carrier frequency filters. 



