Signalling through space without wires : being a description of the work of Hertz & his successors . nval—but it must be well damped), the meaning of these ticks isrecognised; each represents a minute change in the resistanceof the coherer—not at all the full change usually employed,but little subsidiary changes, sometimes up and sometimesdown, barely sufficient to affect a galvanometer, but quiteadequate (being so sudden) to disturb a telephone. Thismethod of receiving, which at first is very sensitive, after atime becomes less so; the point shows signs of fatigue,probably due to too perfect
Signalling through space without wires : being a description of the work of Hertz & his successors . nval—but it must be well damped), the meaning of these ticks isrecognised; each represents a minute change in the resistanceof the coherer—not at all the full change usually employed,but little subsidiary changes, sometimes up and sometimesdown, barely sufficient to affect a galvanometer, but quiteadequate (being so sudden) to disturb a telephone. Thismethod of receiving, which at first is very sensitive, after atime becomes less so; the point shows signs of fatigue,probably due to too perfect cohesion having been graduallyestablished, and a mechanical tap back is desirable to restoreit to its original condition. If all the signals received were precisely of the samestrength, I doubt if these superposed crimples of resistancewould occur; but signals depending on quality of sendingspark never are of the same strength, and accordingly thesudden slight variations of resistance do occur. Usuallyan ordinary high-resistance telephone was employed, and it was SIGNALLING WITHOUT WIRES. 27. SZEO^ZZZZZZZTZZ Simplest Receiving Arrangement: a Telephone in Circuit with Singlepoint Coherer without Tapper-back. B a needle resting against a watch-spring A adjusted by screw C.
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Keywords: ., bookcentury1900, bookdecade1900, bookidsi, booksubjectelectricity
