. Practical wireless telegraphy; a complete text book for students of radio communication . F. decreases frommaximum to zero; from 180° to 270° the current reverses and the E. M. F. increases fromzero to maximum, and from 270° to 360° the E. M. F. again decreases from maximum tozero. The changes in the strength of the current induced in A, B, can be shown by a wave-likecurve as in Fig. 22, in which the successive positions of the rectangle are shown by thepositions, 1, 2, 3, 4, 5, 6, 7, 8, etc. From position 8-16 the E. M. F. gradually rises, maximumE. M. F. being attained in position 4-12. Th
. Practical wireless telegraphy; a complete text book for students of radio communication . F. decreases frommaximum to zero; from 180° to 270° the current reverses and the E. M. F. increases fromzero to maximum, and from 270° to 360° the E. M. F. again decreases from maximum tozero. The changes in the strength of the current induced in A, B, can be shown by a wave-likecurve as in Fig. 22, in which the successive positions of the rectangle are shown by thepositions, 1, 2, 3, 4, 5, 6, 7, 8, etc. From position 8-16 the E. M. F. gradually rises, maximumE. M. F. being attained in position 4-12. This increase of E. M. F. is indicated by theascending slope of the curve B to C. From position 4-12 on, the E. M. F. decreases (asindicated by the descending slope of the curve B to C), the minimum cutting of the linesof force taking place at point 8-16. This corresponds to the point X on the horizontal the rectangle continues the revolution, the lines of force are cut on an increasmg angle,another maximum of E. M. F. being attained at point 12-4, but of the opposite sign as. Fig. 21- -Showing Position of Armature Conductors forMaximum Cutting. 24 PRACTICAL WIRELESS TELEGRAPHY. shown at point D. From this point the E. M. F. decreases to zero or when the rectangleA, B, is in the position of 16-8. This curve depicts the gradual rise and fall-of the E. M. a dynamo coil and is known as a sine curve, the plotting of which is explained in theprinciples of co-ordinate geometry. The curve shows the relation between time (fractionsof a second) and the strength or amplitude of the current at any given point during thecomplete revolution of a dynamo coil. The curvo represents a complete cycle of alternatingcurrent. Vertical lines drawn from the horizontal A, B, represent time in fractions of asecond. The horizontal lines drawn from the successive positions of the coil, 1, 2, 3, 4, etc.,correspond to the position of the dynamo coil at any particular instant. At points where
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
