. Practical wireless telegraphy; a complete text book for students of radio communication . verby a distant transmitting station can be shown by the curves of Fig. 180, whichindicate first: the oscillations of the incoming signals; second, the potential ofthe ^rid circuit with respect to the Mament; third, the decrease of the wing cur-rent and the superposed oscillations ofradio-frequency, and finally, the result-ing fluctuation of current in the headtelephone. Either the current of radio- oraudio-frequency reproduced in the lo-cal circuit of the vacuum valve can beincreased in amplitude by sp
. Practical wireless telegraphy; a complete text book for students of radio communication . verby a distant transmitting station can be shown by the curves of Fig. 180, whichindicate first: the oscillations of the incoming signals; second, the potential ofthe ^rid circuit with respect to the Mament; third, the decrease of the wing cur-rent and the superposed oscillations ofradio-frequency, and finally, the result-ing fluctuation of current in the headtelephone. Either the current of radio- oraudio-frequency reproduced in the lo-cal circuit of the vacuum valve can beincreased in amplitude by special con-nections on the same valve or by con-necting a number of valves in the first method, the current ofradio- or audio-frequency is repeatedback to the grid circuit by specialradio- or audio-frequency transform-ers, but in the second method, a trans-former is connected in the local battery circuit and its secondary terminals con-nected to the grid and filament of a second valve by which the incoming radio signalis amplified by repetition of the action shown in Fig. Fig. 181—Repeater or RegenerativeValve Circuit. Vacuum RECEIVING CIRCUITS, DETECTORS, TUNING APPARATUS. 161 The three element vacuum valve connected in a simple tuning circuit for the receptionof spark signals is adjusted for the maximum strength of signals as follows: (1) Theincandescence of the lamp filament is carefully adjusted by the filament rheostat; (2) Thevoltage of the local battery is varied until the maximum strength of signals is protect the filament and assist adjustment, modern sets have a small ammeter connectedin series with the lamp filament by which the degree oj incandescence is definitely fixed. 143. A Repeater Vacuum Valve Circuit.—A method for repeating, thecurrent of radio frequency flowing in the telephone circuit back to the grid circuitof the same bulb appears in Fig. 181. This system has been found to be particularlysuccessful in operation and gives i
Size: 1936px × 1291px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
