An elementary book on electricity and magnetism and their applications (1919)
Jackson, Dugald C. (Dugald Caleb), 1865-1951, Jackson, John Price, b. 1868, Black, Newton Henry, b. 1874 · New York, The Macmillian Co · leaf 625
Spark gap for 0.25 and0.5 k\v. r? Oiled Silk| Copper Disc v. a A. V m vl As \l V A C] a Fig. 411.— Diagram of quenched.-park gap. … 558 ELECTRICITY AND MAGNETISM transformer secondary, and ground) is left free to vibrate in itsown period and so radiates waves of but one length. The wireless key (Fig. 412) is much like the ordinary Morsetelegraph key except that it is made heavier and has largesilver contacts instead of platinum…
Electricity · Magnetism
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