The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 140
Fig. 121 Fig. 122 and the transmitter battery are both dispensed with, andsometimes also the induction coil. This reduction is, however,partly counterbalanced by the addition of a condenser. … Fig. 123 Fig. 126 shows the connections of the simplest form of C.B.instrument, from which it will be seen that when the receiveris on its rest the loop is connected to the ringer, but with acondenser interposed, so that the circuit is really incompleteso far as a direct current is concerned.…
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Telephones and telegraphs: 1902 : [and Municipal electric fire alarm and police patrol systems] (1906)](https://img.insideoutlibrary.com/img/200/ia-cu31924022817674-68-27.webp)
