Radio, miracle of the 20th century ... a story of human achievement that stands unrivalled in the history of humanity, together with a colorful portrayal, giving a broad, general view of the whole subject of wireless telegraph and telephone and its marvelous development (1922)
Drinker, Frederick E. [from old catalog], Lewis, James G., [from old catalog] joint author · [Philadelphia, Printed by National publishing co.] · leaf 180
tal will bemore satisfactory to the beginner. The crystal detector may be made up of a tested crystal,the wood screws, short piece of copper wire, a nail, set-screw type of binding post, and a wood knob or cork.The tested crystal is held in position on the wood base bybrass wood screws as shown at… … Phone (T, Fig. 3)—It is desirable to use a pair oftelephone receivers connected by a head band, usuallycalled a double telephone headset. The telephone re-ceivers may be any of the standard commercial makeshaving a resistance of between 2,000 and 3,000 ohms, 158 RADIOTELEPHONY The double telephone…
Radio
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