Elements of Radiotelegraphy

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D. Van Nostrand Company, 1919 - Telegraph, Wireless - 267 pages

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Page 1 - Color — then — as we detect it by the eye, is merely a distinction between light waves of different length. Waves striking the retina of the eye at different rates of vibration cause different vibrations or impressions on the retina to be recorded, and these different impressions we call color. 6. The color red, we have seen, has a longer wave length than the color yellow. The colors of the rainbow, red, orange, yellow, green, blue and violet range successively in wave length from about 750 millionths...
Page 36 - ... polished and protected from ultra-violet light so as to supply the electric charge in as sudden a manner as possible. As charged surfaces or capacity areas, spheres or square plates or any other metal surfaces may be employed, but I prefer, for the purpose of combining low resistance with great electrostatic capacity, cones or triangles or other such diverging surfaces, with the vertices adjoining and their larger...
Page 26 - ... they gradually come to rest. Sonorous bodies, such as string under tension, and confined portions of air, as in the organ pipe, are further illustrations suggested by the term. Just as very feeble impulses applied to a pendulum at rest, at intervals exactly corresponding to its natural period of vibration, will cause almost any desired amplitude of swing, so bodies capable of executing vibrations by virtue of their own resiliency may be put into strong vibration by a series of impulses in tune...
Page 189 - The frequency of the beats is equal to the difference between the frequencies of the two oscillating currents.
Page 33 - Current, Forced Alternating: A current, the frequency and damping of which are equal to the frequency and damping of the exciting electromotive force.
Page 14 - E is the EMF in volts, n is the number of turns in the coil, and N is the number of lines of force cut in / seconds.
Page 48 - Thus we say, the potential of the secondary is to the potential of the primary as the number of turns in the secondary is to the number of turns in the primary.
Page 26 - As any circuit possessing inductance and capacity tends to oscillate electrically at its own frequency, it becomes the seat of an induced oscillatory current when subjected to the influence of electric waves of that frequency, each wave giving a slight impulse to the readily excited oscillations, with the result that the induced electromotive forces will be amplified in intensity, just as the swing of a pendulum is amplified by the application of properly timed, though feeble, touches.
Page 174 - ... magnet. The deflexion is ol served by the movement of a beam of light reflected from a small mirror on the Field = 10 15 25 35 62 102 200 400 600 Tube I.

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