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nELL SYSTEM TECHNICAL JOURNAL 



the design was that the spread in the transit angle for zero signal should be 

 small. This requirement is not as stringent as might be expected. The 

 contribution to the electronic conductance by a current element whose 



APPROXIMATE 



ZERO 



EQUIPOTENTIAL 



Fig. 65. — Repeller design for eliminating hysteresis in a reflex oscillator. The electrons 

 make only two transits through the gap. The repeller does not return them to the cathode 

 region hut to the edge sup])orting one of the grids of the gap. Equipotcntials determined 

 from an electrolytic trough investigation are shown and the electron trajectories com- 

 puted from these equipotcntials. 



transit angle deviates from the optimum by a small angle Ad varies as cos A^, 

 so that even for spreads in angle as great as ± 30° the effect is not serious. 

 The design illustrated in Fig. 64 was strikingly effective in reducing 

 hysteresis. Fig. 66 shows repeller characteristics for the original design 

 which was extrapolated from the 723A/I5 and for the design of Fig. 64, 



