. An elementary manual of radiotelegraphy and radiotelephony for students and operators . llations, the amplitude of which vary continuously, then theequivalent resistance of the cell varies continuously, and in somedegree proportionately to the intensity of the electric oscillations. 2l8 RA DIO TELEGRA PH Y This important fact has been applied, as shown in Chapter IX.,in connection with radiotelephony, and has been made the meansby which undamped electromagnetic waves are made to conveyarticulate speech between two points without the use of con-tinuous connecting wires. A form of detector whi
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . llations, the amplitude of which vary continuously, then theequivalent resistance of the cell varies continuously, and in somedegree proportionately to the intensity of the electric oscillations. 2l8 RA DIO TELEGRA PH Y This important fact has been applied, as shown in Chapter IX.,in connection with radiotelephony, and has been made the meansby which undamped electromagnetic waves are made to conveyarticulate speech between two points without the use of con-tinuous connecting wires. A form of detector which is by some classified as an imperfectcontact and by others as an electrolytic detector is that inventedby S. G, Brown. It consists of a pellet of peroxide of lead heldbetween a plate of lead and one of platinum. If an from a single secondary cell is impressed upon it so thatthe current flows through the peroxide from platinum to lead, thiscurrent will experience a counter electromotive force due to theelectro-chemical action of the lead-peroxide of lead-platinum ISfP. [Reproduced by permission of the Cambridge Scientific Instrument Company,Fig. 17. couple. According to Mr. Brown, when oscillations pass throughthis couple they increase its counter-electromotive force by stimu-lating chemical action and so reduce the current sent through itby the external cell. The couple acts, therefore, as a conductor ofwhich the resistance is increased by electric oscillations. Thepellet of peroxide is mounted up in a holder so as to apply to itan adjustable pressure (see Fig. 17), and is placed in series with agalvanometer and single cell. When oscillations are createdthrough the peroxide the deflection of the galvanometer decreasesbut increases again when they cease. 7. Valve or Rectifier Oscillation Detectors.—Since electricoscillations are alternating currents of high frequency, themeans of detecting them simply as electric currents which OSCILLATION DETECTORS 219 bavo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
