. An elementary manual of radiotelegraphy and radiotelephony for students and operators . he bolometer wire. If oscillations are then sent throughthe latter, they still further heat the loop and suddenly decreasethe currvint through the telephone. The ear then detects thisdecrease of telephonic current by a sound made in the telephone. OSCILLATION DETECTORS 213 1 1 foiuul timi in pluco of the pliilimiin wire a fine IuIh- Mth u lu^h rtsislimco lie airan{.;ed in parallel to be heatedby tlie san>e oscillations. (3) We n>ay use a thermoelectric couple to detect a smallrise of teiiii>tiatu
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . he bolometer wire. If oscillations are then sent throughthe latter, they still further heat the loop and suddenly decreasethe currvint through the telephone. The ear then detects thisdecrease of telephonic current by a sound made in the telephone. OSCILLATION DETECTORS 213 1 1 foiuul timi in pluco of the pliilimiin wire a fine IuIh- Mth u lu^h rtsislimco lie airan{.;ed in parallel to be heatedby tlie san>e oscillations. (3) We n>ay use a thermoelectric couple to detect a smallrise of teiiii>tiaturc in the wire. Such an armngement firstemployed by Klemencic. The oscillations are sent through afine constantau wire, and against this rests tlio junction of athermoelectric couple made of iron and coustantan, or some otherpair of suitable metals. The ends of the couple are connected. Tig. 12. Fig. 13. to a suitable low resistance galvanometer, and on passing oscil-lations through the high resistance wire the galvanometer givesan indication. An improved arrangement of this kind was devised by theauthor in 190r>, taking advantage of the position of telluriumand bismuth in the thermoelectric series. A sort of doubletest-tube of glass was constructed (.see Fig. 18), the interspacebetween the two tubes being subsequently exhausted. Throughthe bottom of the inner test tube were sealed four wires, two ofthese, a, h, were connected to a fine constantan wire, and theother two. e, d, were connected to a tellurium-bismuth thermo-junction T formed of very fine wires of bismuth and tellurium, the 214 RA DIO TELEGRA PH Y junction being soldered by a special solder to the centre of theconstantan wire. A high vacuum was then made in the interiorspace. When oscillations are passed through the constantan wire,a suitable low resistance galvanometer being connected to theleads fro
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
