The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 169
by the armature, or an attachment to it, isallowed to fall, and expose a number or a coloured surface,which will attract attention. Since magnetic attractiondiminishes very rapidly as the distance of the armature in-creases (actually as the square of the distance), the best effectK 143 144… … Sectional Elevation at JCy. Fig. 155.—Full size can then be adjusted comparatively close to the cores, butmust be prevented by non-magnetic core-pins from actuallytouching when attracted. The Western Electric Co.s two-coil drop is constructed xf /»_ P
Telephone
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