The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 101
A cap with a funnel mouthpiece is thenscrewed on, as shown. The bottom of the funnel had gener-ally a piece of wire gauze, or some crossed wires, fixed over it,to prevent the foil being damaged by thoughtless personspoking it with pencils, etc. The instrument was generallyheld in the hand while… … Fig. 68 TRANSMITTERS IN PRACTICAL USE 79 that instead of a platinum diaphragm one of thin pine woodwas employed, having fixed to its centre a thin block ofcarbon connected by a fine wire to one of the terminals. The Solid-Back.—This transmitter, invented by Mr A. C.White in America, has achieved…
Telephone
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