. The principles and practice of roentgenological technique . lsating current is acontinuous current which varies regularly. Aconstant current is one which continues in itsflow for some time with unvarying may be either direct or alternating. Analternating current is one which reverses itsdirection at regular intervals. The time is measured horizontally from leftto right on the horizontal OX. The strength A B 5. ^ 3 <^_ A1A p A / \ A / * 3 C \ A ;\ \ iA y V V y V V y Fig. /.—Current curve of a three phase successive alternating currents, a, b, c, areoutlined. When o
. The principles and practice of roentgenological technique . lsating current is acontinuous current which varies regularly. Aconstant current is one which continues in itsflow for some time with unvarying may be either direct or alternating. Analternating current is one which reverses itsdirection at regular intervals. The time is measured horizontally from leftto right on the horizontal OX. The strength A B 5. ^ 3 <^_ A1A p A / \ A / * 3 C \ A ;\ \ iA y V V y V V y Fig. /.—Current curve of a three phase successive alternating currents, a, b, c, areoutlined. When one is at its positive maximumvalue, the other two are each at negative halfvalue. When any one is at zero value, theother two are at of the maximum, one pos-itive and the other negative. and direction of the current at any part areindicated by the length of the vertical ordi- nates and their positions relative to the baseline. The total horizontal line OX measuresonly a fraction of a second. Each succeedingpositive half wave is exactly similar to the. Fig. 8.—The curves OT represent the current flow-ing in a given circuit. OR represents the alter-nating e. m. f. in the circuit. The periodicityof these two quantities is the same and theyare also in phase. But the curve LX whichrepresents another e. m. f. lags behind OR andthere is therefore a difference in phase betweenthem equal to ^ of a period. preceding one and the same similarity existsbetween the negative half waves. The cur-rent rises and falls through a certain repeatedcycle of values. The time required for the
Size: 1721px × 1452px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectradiogr, bookyear1920
