The telephone system of the British post office. A practical handbook (1901)
Herbert, Thomas Ernest · London, New York, Whittaker and Co. · leaf 46
Figure 22. The cones keep the granules well distributed, and thus uniformity ofcontact is secured. In order to prevent the trouble which arises fromthe granules becoming packed at the bottom of the cones, the diaphragmis fitted with a woollen ring F F, so that only the granules in the centreof the… … Figure 23. fitted with little tufts of silk at their points, and tend to damp out anyvibrations which are not continuously sustained, and, as we have seen, an 32 Solid-Back Transmiiley. efficient transmitter must on no account be a persistent vibrator. Oneterminal of the instrument is formed by the…
Telephone · Postal service
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