. The Bell System technical journal . Lb+Lc LaLc r,=FA/(2. r,=F-U23, La + Lb + Lc r,^M[s, \vh La = Li±M{2±M\3, Lb = Li ± M12 ± M23,Lc=L,±My.,±M:,,. (83)(84)(85) (86)(87)(88) (89)(90)(91) As in the preceding case, the upper of the two signs occurs with theseries aiding mutual inductance between all the pairs of coils. \\ henthe mutual inductance between any two coils changes sign, the signsacct)mpan\ing thai nnitual inductance in the above formulae arere verse* I. At least two of the three inductances (in Fig. 33M or in Iig. 34B)will be positive in sign while the third inductance may be
. The Bell System technical journal . Lb+Lc LaLc r,=FA/(2. r,=F-U23, La + Lb + Lc r,^M[s, \vh La = Li±M{2±M\3, Lb = Li ± M12 ± M23,Lc=L,±My.,±M:,,. (83)(84)(85) (86)(87)(88) (89)(90)(91) As in the preceding case, the upper of the two signs occurs with theseries aiding mutual inductance between all the pairs of coils. \\ henthe mutual inductance between any two coils changes sign, the signsacct)mpan\ing thai nnitual inductance in the above formulae arere verse* I. At least two of the three inductances (in Fig. 33M or in Iig. 34B)will be positive in sign while the third inductance may be IX riilier (H>siti\o or lu-^ative. (()iisi(|iun(l\, llirro coils haviiij; nuitiialiruluctanci iHMwttii i-acli of tlu-m and ha\inK only three arcessihieterminals offer no ^■•■•i* l)j nnitiialitidiictance Iwlvveen them and havinjj three terminals. In liolhcases the structure is etiiiivalent to a 7or w mesh composed of three self. Fig. 35—Equivalent Filter Sections, With .mil Without Mutual Iiulurtanrc inductances, at least two of which must be positive. With specificrelations between the various self anfl mutual inductances, it is possi-ble for the three coils with mutual inductance between each of themto be equivalent (as in the case of two coils with mutual inductance)simply to an L network composed of two positive self either two or three coils with mutual inductance betweenthem are, in general, equivalent, at all frequencies, to a T or v net- 94 BELL SYSTEM TECIIXtCAL JOURNAL work composeti of three s(.-lf incluctances, it is possible to substitutethe one t>[K of mesh for tlie other in any kind of a circuit willioutaffecting the currents or voltages external to tlie meshes substitution is always physically possible provided none of thearms of the equivalent 7 or tt networks is a negative inductance. The structures shown in Fig. 35 are illustrative of the power ofequival
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
