. The telephone system of the British post office. A practical handbook . itch-spring allows the call battery to join with thesubscribers permanent current battery, thus overcoming the bias of hisrelay and ringing his bell. The switch-board telephone is connected to a peg divided into fourparts, which in turn fits into the switch-spring upon the tablet. Thisswitch-spring consists of four springs, which are in turn connected to thestationary apparatus. The connection between the telephone and peg ismade by means of four conductor flexible cord. Switch-Board Telephone Tablet. 63 When the lever i
. The telephone system of the British post office. A practical handbook . itch-spring allows the call battery to join with thesubscribers permanent current battery, thus overcoming the bias of hisrelay and ringing his bell. The switch-board telephone is connected to a peg divided into fourparts, which in turn fits into the switch-spring upon the tablet. Thisswitch-spring consists of four springs, which are in turn connected to thestationary apparatus. The connection between the telephone and peg ismade by means of four conductor flexible cord. Switch-Board Telephone Tablet. 63 When the lever is at rest the two halves make contact with the twobottom springs. The four-way peg carries a projection which fits thetop switch-spring, thus preventing the peg being inserted-upside primary circuit is from either speaking battery according to whichposition the two-way switch occupies, through the centre of the two-wayswitch, through the primary of the induction coil to the left top spring,thence through left top quarter of the peg through the microphone, back. Figure 52, through the bottom left hand switch-spring to the left hand side of thedivided lever, through the left hand bottom spring back to the will be seen that when the lever is depressed the primary circuit isbroken, thus preventing the battery from being run down. The secondarycircuit is from the upper switch-spring upon the switch board ^shown atthe side of the tablet) through the right hand side of the divided lever,through the right hand bottom spring, through the secondary of the inductioncoil to the top right hand spring, through the receiver back to the left 64 CovneciioftS, hand bottom spring (which we have seen also serves for one side of themicrophone) to the bottom spring of the switch-spring from which westarted. The button upon the telephone when depressed connects thebottom right switch-spring to the top right spring. The secondary of theinduction coil is thus short-circuited from th
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelepho, bookyear1901
