Lessons in practical electricity; principles, experiments, and arithmetical problems; over four hundred illustrations; an elementary text book (1909)
Swoope, C. Walton (Coates Walton), d. 1901 · New York, D. Van Nostrand company · leaf 351
al is grounded, Fig. 302. Atelegraph key, Fig. 298, is introduced into the primary circuitof the induction coil, whereby the dot and dashsystem of signals may be used. Details of the receiving appa-ratus are shown in Fig 302. A small glass tube (say J inchinside diameter) contains two plugs of…
Electricity · Magnetism
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