American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 380
of one polarity, say, positive; the other sends negative polarityto the line. Two wires are used between stations. The receiver is a telephone, thediaphragm of which is set into oscillation by the current pulsations, the direction ofthe oscillation corresponding to the polarity of the current… … p. -m TRANSMITTING AND RECEIVING CIRCUITS. RECEIVING apparatus; condenser is placed around the telephone to prolong the duration of the currentimpulses and to steady the oscillation of the mirror. A snudl incandescent lamp iscaused to throw .a beam of light on the mirror, which beam is reflected by…
Telegraph
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