. An elementary manual of radiotelegraphy and radiotelephony for students and operators . t of it is now called a characteristic curve. Hence, for ordinarymetallic conductors, the characteristic curve is a straight line risingupwards with increasing current, and is called a straight risingcharacteristic curve. If, however, a series of observations are madeby means of a voltmeter and ammeter on an electric arc betweencarbon rods, we find a totally different form of characteristic we measure the current through the arc and thepotentialdifferenceof the carbons for various constant length
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . t of it is now called a characteristic curve. Hence, for ordinarymetallic conductors, the characteristic curve is a straight line risingupwards with increasing current, and is called a straight risingcharacteristic curve. If, however, a series of observations are madeby means of a voltmeter and ammeter on an electric arc betweencarbon rods, we find a totally different form of characteristic we measure the current through the arc and thepotentialdifferenceof the carbons for various constant lengths of arc, and plot a curveshowing the relation between the two for various cun-ents throughthe arc, we obtain a curve which is concave upwards and slopesdownward as the current increases ; in other words, we have afalling characteristic (see Fig. 11). An increase in the arc currentis accompanied by a decrease in the potential difference of thecarbons. Hence the arc considered as a conductor differs essentiallyfrom a metallic conductor, and does not obey Ohms law. 94 RADIO TELEGRA PH Y. The characteristic curve of the arc is therefore a curve whichslopes in the opposite direction to that of conductors which do obey Ohms law. Moreover, H. has furthermore distin-guished between the so-calledstatic characteristic and the dy-namic characteristic of the former is a curve whichdelineates the relation betweentlie arc current and the arc elec-trode potential difference ()when these quantities are slowlyvaried and in one direction, andthe latter is a curve which de-lineates the relation betweencurrent and when thesequantities vary periodically andin a cyclical manner, as in the alternating current arc. The static characteristics of carbon arcs have been determinedand described for many different arc lengths and carbon sizes andqualities, particularly by Mrs. Ayrton. The static characteristicsfor arcs between carbon and metal electrodes and in various gaseshave be
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
