. The Bell System technical journal . Fig. 13—Comparative size of equivalent 1939 and 1922 cases. are suitable for use in this range. For comparison, similar charac-teristics are also included for coils using cores of equal size but madeof permalloy and electrolytic iron powder. These data include alleffects on Q resulting from winding capacities and losses, which have 402 BELL SYSTEM TECHNICAL JOURNAL been made tolerably small by suitable choice of insulating materials,stranding of conductor and configuration of winding. Conclusion Compressed powdered cores of 2-81 molybdenum-permalloy havepr
. The Bell System technical journal . Fig. 13—Comparative size of equivalent 1939 and 1922 cases. are suitable for use in this range. For comparison, similar charac-teristics are also included for coils using cores of equal size but madeof permalloy and electrolytic iron powder. These data include alleffects on Q resulting from winding capacities and losses, which have 402 BELL SYSTEM TECHNICAL JOURNAL been made tolerably small by suitable choice of insulating materials,stranding of conductor and configuration of winding. Conclusion Compressed powdered cores of 2-81 molybdenum-permalloy haveproperties which are superior to those of earlier powdered cores inrespect to permeability range, hysteresis loss and eddy current of the lower losses and greater permeability range, inductancecoils are now possible which have greatly increased Q values for a givenvolume. Because of the low hysteresis losses and attendant lowering. Fig. 14—Comparative size of non-magnetic core and molybdenumpermalloy core filter coils. of modulation effects to tolerable levels, magnetic core inductancecoils can now be employed where non-magnetic core coils have pre-viously been necessary, with a very great increase in Q values for agiven volume. Temperature coefficients can now be obtained whichare equal to the temperature coefificients of other high grade electricalelements such as mica condensers and quartz crystals. Moreover, theability to make the temperature coefficient of coils negative or positiveat will permits the attainment of remarkable stability in resonantcombinations of coils and condensers. Two important applicationshave been made in the field of communication apparatus. For voice-frequency circuits, new loading coils of improved quality and reduced MOLYBDENUM PERMALLOY FOR INDUCTANCE COILS 403 10UJ X u z ii u o ^ 3 <q3 O < /, / ^ / / 7 // in zo 10 z UJ 2QUJ rr LU- 3 - ! - ^ / / a DO a. / • ai <0<
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
