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THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1957 



more stable than usual was required. This was true of the high voltage 

 capacitors where other requirements dictated the use of impregnated 

 paper as the dielectric but where the degree of stabiUty required was 

 comparable to that expected of more stable types of capacitors. In so 

 far as possible, stabiUty was built into the components by appropriate 

 design but, where necessary, stabiUzing treatments consisting of re- 

 peated temperature cycles were used to accelerate aging processes to 

 reach a stable condition prior to assembly of the repeaters. Temperature 

 cycling or observation over periods up to six months were used also to 

 determine that the components' characteristics were stable. 



Exceptional inspection procedures followed to insure reliability and 

 stability are described in detail in a companion paper.^ 



As mentioned earlier, the design and construction of components was 

 simplified by omitting housings or containers, except for oil impregnated 

 paper capacitors. Adequate mountings for the components were obtained 

 in several ways. Mica capacitors were cemented to small bases of methyl 

 methacrylate which were in turn cemented in suitable recesses in net- 

 work structures. Inductors and transformers were cemented directly 

 into recesses in the network housings. Fig. 14 illustrates some of these 

 structures and their mounting arrangements. On the bottom is a molyb- 

 denum permalloy dust core coil in which a mounting ring of methyl 



Fig. 14 — Mounting for molybdenum permalloy dust core coils. 



