. An elementary manual of radiotelegraphy and radiotelephony for students and operators . of condensers C (seeFig. 14), we have an arrangement capable of producing electricoscillations of great power. Usually the alternator A produces an alternating currentat a voltage, say, of 2000 and frequency of 300 to 500. Thetransformers T transform up this voltage, say, to 20,000, corre-spondingly reducing the current. The condenser C is thuscharged to 20,000 or oO,000 volts or so, and the spark gap Smay be 5 to 10 millimetres in length. The condenser thendischarges across this spark gap at intervals, p
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . of condensers C (seeFig. 14), we have an arrangement capable of producing electricoscillations of great power. Usually the alternator A produces an alternating currentat a voltage, say, of 2000 and frequency of 300 to 500. Thetransformers T transform up this voltage, say, to 20,000, corre-spondingly reducing the current. The condenser C is thuscharged to 20,000 or oO,000 volts or so, and the spark gap Smay be 5 to 10 millimetres in length. The condenser thendischarges across this spark gap at intervals, producing at eachdischarge a train of high frequency oscillations, the frequencybeing determined by the capacity of the condenser and the DAMPED ELECTRIC OSCILLATIONS 57 inductances, P, L, in series with it. It mi^ht be thought thatsince the charging voltage is alternating, or lirst in one directionand then in the other, tluit one condenser discluirge or train ofosciUations wiuiUl occur at each instant of maximuin cliargingvoltage, and therefore that the number of condenser discharges. 4l|l|l|l|l|l|l|l|i|l|lB Fig. U. per second would be double the frequency of the chargingvoltage. This, however, is not the case. The number of con-denser discharges per second may be much greater or much lessthan twice the frequency of the alternating current w^hich issupplied to the transformers for the following reasons:— If the transformers have a very high secondary inductance, orhave inductance coils placed in series with their secondary circuitsbetween the transformer terminals and the spark balls, and if thespark balls are set near together, the condenser may becomecharged to a potential which will enable it to discharge across thisgap long before the periodic electromotive force of the transformerhas reached its maximum value, as it increases from zero. Themoment the discharge happens the condenser empties itself, and ifthere is no sensible arc discharge diie to the transformer itself be
Size: 2340px × 1068px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
