. An elementary book on electricity and magnetism and their applications. h is attached to theaerial and ground. (3) The Chaffee gap consists of a minute gap in hydrogenor alcohol vapor between a copper anode and an aluminumcathode, as shown in figure 422. Except for the difference inthe metal of the two terminals, the halves of the gap are sym-metrical. Each terminal is inserted in a heat-radiating sup-port. The form of gap shown is made air-tight by the use of a flexible phosphor bronze a diaphragm permits the nec-essary adjustment of the condenser and inductance a
. An elementary book on electricity and magnetism and their applications. h is attached to theaerial and ground. (3) The Chaffee gap consists of a minute gap in hydrogenor alcohol vapor between a copper anode and an aluminumcathode, as shown in figure 422. Except for the difference inthe metal of the two terminals, the halves of the gap are sym-metrical. Each terminal is inserted in a heat-radiating sup-port. The form of gap shown is made air-tight by the use of a flexible phosphor bronze a diaphragm permits the nec-essary adjustment of the condenser and inductance areshunted about the gap and this con-stitutes the primary circuit just asin the Poulsen circuit; but with theChaffee gap the primary circuit isnot an oscillatory circuit, for the gapacts as a rectifier and permits onlydirect-current impulses to flow from the copper to the alumi-num. One of these impulses starts oscillations in the second-ary current. The frequency of these impulses is controlled bythe condenser, inductance, and main supply of current. Such Cooling Fins. Fig. 422. — Section of Chaffeegap. 566 ELECTRICITY AND MAGNETISM a gap may be used to get any frequency up to 30,000,000 cyclesper second. Whatever the generator of the high-frequency oscillatingcurrent, the microphone transmitter must be of large current-carrying capacity and so sometimes a water-cooled trans-mitter is used. 382. Use of radiotelephony. Although the radiotelephoneis not yet in commercial use, it is practicable to employ itup to 200 miles. In its present form, however, there seemsto be little demand for such a device. On account of its deli-cate and complicated apparatus it obviously cannot take theplace of the ordinary telephone, and its limitations in regardto power unfit it for long-distance service. Undoubtedly itwould find a use in the navy if the apparatus could be is only reasonable to expect, however, that the range ofpossible wireless telephony will be less than, but will
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