. An elementary manual of radiotelegraphy and radiotelephony for students and operators . from the rush of current through a high , in the absence of definite proof that undamped and un-interrupted oscillations were obtained by this method, we havea right to suspend judgment upon the result. 4. Poulsens Method of Producing Undamped High Frequency 98 JiA DIO TELEGRA PHY Oscillations.—In 1903 -Yalilemar Poiilsen, of Copenhagen, describedimportant improvcmenls in the arc method of creating electricoscillations which give fresh importance to the matter. Heproduced an electric arc b
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . from the rush of current through a high , in the absence of definite proof that undamped and un-interrupted oscillations were obtained by this method, we havea right to suspend judgment upon the result. 4. Poulsens Method of Producing Undamped High Frequency 98 JiA DIO TELEGRA PHY Oscillations.—In 1903 -Yalilemar Poiilsen, of Copenhagen, describedimportant improvcmenls in the arc method of creating electricoscillations which give fresh importance to the matter. Heproduced an electric arc between a carbon rod as the negativeand a copper rod as the positive terminal, the latter being kept coolby a water circulation within it. The arc was at the same timesurrounded by an atmosphere of hydrogen or a hydrocarbon gas orvapour, and crossed transversely by a strong magnetic field. Onshunting this arc with an oscillation circuit consisting of a smallcapacity and a large inductance, he found that he obtained in thiscircuit very powerful undamped or persistent oscillations, the. ^mm.^M^ frequency of which, by a proper selection of capacity andinductance, could be made to be as high as a million or more,and quite within the range of those required for radiotelegraphicwork. Before proceeding to explain the reasons for the increase infrequency obtainable by the above means, it will be best to describemore in detail the construction of Poulsens apparatus, andsome of the modifications of it which have been suggested. The electric arc is formed with a direct current voltage of 400to 500 volts between the end of a solid carbon rod, about 1 inch indiameter, and the end of a water-cooled copper pole (see Fig. 13),The latter consists of a copper tube, which is closed at both ends UXDAMPED ELECTRIC TIOXS 99 h: rn ^ c ^ M and has an inlet niul exit pipo for ciiruliitiii^ cold water throughit. Tlie end of tliis tube terniiiuitcs iu a sharp copper uose piece,which is
Size: 1833px × 1363px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
