Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 38
FIGS. 15 AND le.-BERLINEES PATENT-OFFICE MODEL. THE BATTERY TRANSMITTER. 17 num disc secured to the diaphragm. The plumbago button washeld against the diaphragm by a spring, the tension of which couldbe adjusted by a thumb-screw. A form of Edisons transmitter, devised by George M. Phelps in1878, is…
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