G78 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1956 



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FREQUENCY IN CYCLES PER SECOND 



Fig. 16 — Relative rectification efficiency versus frequency. 



of these same devices. Such relationships among the measurable param- 

 eters of these devices make it possible to design and control the elec- 

 trical characteristics of the units and therefore make them extremely 

 attractive from an engineering point of view. 



6.0 MECHANICAL AND THERMAL DESIGN 



6.1 In order to have a device that is usable for more than experimen- 

 tal purposes, it is necessary that it be packaged in a mechanically stable; 

 structure and that the heat generated in the combined unit should not' 

 lead to a condition ^vhere the device no longer has its desirable charac- 

 teristics. In earlier sections of this paper several mechanical require- 

 ments of a satisfactory package have been suggested. These may be 

 repeated at this point. First, pressure contacts are not satisfactory; sec- 

 ond, oxidizing ambients are to be avoided; third, approximately one 

 watt per ampere of forward current is generated and must be disposed ; 

 and fourth, the package must be electrically satisfactory. The first rc- 

 (juirement is met by using soldered contacts. Since these rectifiers are, 

 usable at temperatures over 200°C, a solder was chosen that has a melt- 

 ing point over 300°C. The second recjuirement necessitated the use of 

 a hermetic seal structure. If the seal is truly hermetic, no gases can 



