A text book of physics, for the use of students of science and engineering (1918)
Duncan, John, d. 1941, Starling, Sydney George, 1873- · London Macmillan · leaf 1032
E E Fig. 947.—Duplex telegraph (differential). With this arrangement the line is available for sending messagesin both directions simultaneously, since at either station a depressionof the key does not affect the galvanometer at that station, but doesaffect the galvanometer at the other end of the…
Physics
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