. The London, Edinburgh and Dublin philosophical magazine and journal of science. s taken by the characteristic, where variable currentsor inhomogeneous conductors are concerned. If the charac-teristics of two conductors are known, the characteristicof a conductor composed of the two can be constructed fromthem. Here the following laws for coupling in series andparallel coupling of the two characteristics hold good. A. Coupling in Series.—For a certain strength of current (i) the two *-values are added. B. Parallel Coupling.—For a certain voltage (<?) the two 2-values are added. Fig. 2. / i
. The London, Edinburgh and Dublin philosophical magazine and journal of science. s taken by the characteristic, where variable currentsor inhomogeneous conductors are concerned. If the charac-teristics of two conductors are known, the characteristicof a conductor composed of the two can be constructed fromthem. Here the following laws for coupling in series andparallel coupling of the two characteristics hold good. A. Coupling in Series.—For a certain strength of current (i) the two *-values are added. B. Parallel Coupling.—For a certain voltage (<?) the two 2-values are added. Fig. 2. / i(l) / j£~ / / ^ $fc*U Fig. 2 shows the graphical construction of the charac-teristics in question. If the voltage (E) and the two characteristics are given 3S2 972 Mr. M. Siegbahn on the Study of Variable we are in possession of the means necessary for the deter-mination of the e- and /-values. According to the additionaltheorem e »/,(*) +/,(£), (3) or E-/,(i) =/„(«) (4) This alteration of oar formula gives as a simple method ofgraphically finding the e- and From the line e=E, J\(j) is sel off : its intersection withf2(i) is the required point of equilibrium A. From this Kauffmanns conditions of stability are easilyfound. From (3) is obtained by differentiation with respectto the strength of current (/), f i / j d/ L of* Oi Oi (5) for a stable equilibrium, it is reqnired that this expressionshall be greater than the given voltage E ; or (6) ()(8) stable : \fi +1& > 0 o* Ol indifferent : di o* unstable: M + M<0. 0« Oi ,. M Graphically :— signifies the angular coefficient of thetangent at the point in question. Currents by means of the Phaseograph. 973 II. Methods of Registering Characteristics. We can distinguish between two different kinds of charac-teristics. A. Statical characteristics. B. Dynamic characteristics. A refers to stationary or quasi-stationary currents; thesecan be registered by ordinary voltmeters or ammeters. B, thedynamic character
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectscience, bookyear1840
