. The Bell System technical journal . y emission. Procd. Inst. Radio Engrs., Vol. 6, p. 5, 1918. 24 J. M. Miller, Proc. I. R. E., Vol. 6, p. 141, 1918. For variations of Millersdynamic method the reader is referred to Van der Bijl, 1. c, p. 198, Method of G. 44 BELL SYSTEM TECHNICAL JOURNAL Millers method is illustrated in Fig. 13. To determine n the keyKi is open and Ki is closed. The resistance r\ is adjusted until thesound heard in the telephones T is a minimum, under which circum-stances it is clear that u=—. To determine rp, some definite relation between r\ and ri is establi
. The Bell System technical journal . y emission. Procd. Inst. Radio Engrs., Vol. 6, p. 5, 1918. 24 J. M. Miller, Proc. I. R. E., Vol. 6, p. 141, 1918. For variations of Millersdynamic method the reader is referred to Van der Bijl, 1. c, p. 198, Method of G. 44 BELL SYSTEM TECHNICAL JOURNAL Millers method is illustrated in Fig. 13. To determine n the keyKi is open and Ki is closed. The resistance r\ is adjusted until thesound heard in the telephones T is a minimum, under which circum-stances it is clear that u=—. To determine rp, some definite relation between r\ and ri is established. Then, with key K\ closed, the re-sistance r0 is adjusted until the telephone response is a this adjustment it may be shown that rP = r0U^-l\. (3) This measurement of rp may be simplified as follows: suppose we adjust Y\ for a minimum tone in T when K\ is open. Then n=— > and it is seen from Equation 3 that with this relation between r\ andr2 it would not be possible to obtain a balance with K\ closed; but if. Fig. 13 r2 be doubled, which can be done by opening Ki thus adding a re-sistance equal to ri, and r0 be now adjusted with K\ closed to give aminimum tone in T, then rP — r0. 12. Dynamic Characteristics of Vacuum Tubes. In a circuit such asthat shown in Fig. 13, the space current causes a fall of potentialalong any resistance r, and the difference in potential between filamentand plate is therefore less than the potential difference across thebattery by the amount IP r. If Ip is increased in any way, as forinstance, by an increase in Eg, the drop Ip r increases and with a fixedbattery the potential difference between the filament and platediminishes somewhat. It follows, therefore, that a given change inEg will cause a smaller change in space current when the plate circuitincludes an external resistance r than when it does not. This important fact supplies a simple means of straightening thecharacteristic of a vacuum tube to such an extent
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