. The Pharmaceutical era. ed with the circuit, and directly in front of the magneta thin iron disk or diaphragm. (Fig. By talking infront of the disk it is thrown into rapid vibration by thesound waves and the motion thus set up produces elee-triosite endthese currents in turn cause varinlions in the magneticfield, causing the disk to alternately approach and recedefrom the magnet, thus reproducing the original sound. Ua£Wre, Fig. 109.—Telephone Transmitter. waves. In such a circuit the transmitter is virtually adynamo and the receiver a motor, and no battery is nec-essary. In the moder
. The Pharmaceutical era. ed with the circuit, and directly in front of the magneta thin iron disk or diaphragm. (Fig. By talking infront of the disk it is thrown into rapid vibration by thesound waves and the motion thus set up produces elee-triosite endthese currents in turn cause varinlions in the magneticfield, causing the disk to alternately approach and recedefrom the magnet, thus reproducing the original sound. Ua£Wre, Fig. 109.—Telephone Transmitter. waves. In such a circuit the transmitter is virtually adynamo and the receiver a motor, and no battery is nec-essary. In the modern instrument the current is supplied by aLeclanche cell, the vibration of the metallic disk serv-ing only to vary the intensity of the current by varyingthe resistance in the circuit. .other improvement is the addition of an inductioncoil which furnishes the current for the line, the Le-clanche cell simply supplying the current for the primarycoil. The result of the addition of the battery and in-duction coil is to increase the strength of the currentswhich traverse the line, intens-ifying the vibration of the diskof the receiving instrument,and rendering the sounds pro-duced more distinct. The completed instrument in-cludes, in addition to the partsalready described, a- small dy-namo contained in the upperpart of the case. (Fig. 110.)When the crank is tiirniNl acurrent is produced which ringsa bell both at the
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Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
