. The Bell System technical journal . >^ •••) + {-T, + k- •••)1 B^ ^ 144 300 12600 (51) The A- may thus be eliminated between (51) and (49) giving <P2 ( — \2B^ 1 + 11600 + 39 140000 + (52) which is in agreement with the result obtained by Benham. The physical explanation of the increase in rectified current whichoccurs when the transit angle becomes appreciable follows directlywhen it is realized that as the frequency is made higher, the funda-mental component of the alternating current increases when the is maintained at constant amplitude. This is because of thecapac
. The Bell System technical journal . >^ •••) + {-T, + k- •••)1 B^ ^ 144 300 12600 (51) The A- may thus be eliminated between (51) and (49) giving <P2 ( — \2B^ 1 + 11600 + 39 140000 + (52) which is in agreement with the result obtained by Benham. The physical explanation of the increase in rectified current whichoccurs when the transit angle becomes appreciable follows directlywhen it is realized that as the frequency is made higher, the funda-mental component of the alternating current increases when the is maintained at constant amplitude. This is because of thecapacitance of the diode. It is this increase in fundamental current ULTRA-HIGH-FREQUENCY VACUUM TUBES 647 which causes the increase in rectified current, and not the effect oftransit angle directly. Part IV—Negative Grid TriodesThe general aspect of the negative grid triode is shown in Fig. upper diagram shows a plan view of the electrode arrangement and 1- ic -Xc-TC B I I ■r I -\- I o I 2 l^-H Va = Vg (NEARLY) vc. Fig. 1.—Nomenclature and potential distribution in negative grid triodes. indicates the nomenclature which will be adopted. The planes at Vcand Vp constitute the cathode and plate, respectively, and the gridwires are indicated by the small circles. The planes A and B areimaginary planes located on opposite sides of the grid and only farenough away so that the irregularities in the potential distributioncaused by the individual negative grid wires have practically disap-peared. An analysis of the potential distribution in the immediateneighborhood of a shielding screen has been made by Maxwell (Treatiseon Electricity and Magnetism Vol. I) and this applies to the grid of thetriode in the absence of electron flow. The presence of electronsbetween the negative grid wires will tend to decrease the irregularitiesshown in Maxwells analysis and therefore allow the planes A and Bto be placed somewhat closer together than his figures would far
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