Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 192
V. The beam of light passes throughthe photographic film and is reflected upward within the MISCELLANEOUS TELEGRAPHS 177 cylinder by the prism P and impinges upon the seleniumcell 5i. The cyHnder T, in addition to its rotary motion,has an axial movement, so that all parts of the photo- 1^… … Fig. II. The receiver, Fig. 11, is provided with a Nernst lamp Lwhich sends out a beam of light through the galvanometershutter h. This galvanometer, called a light-relay, con-sists of an electromagnet d, provided with long perforated 178 TELEGRAPH ENGINEERING pole-pieces pp, between which is…
Telegraph
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