Page:Popular Science Monthly Volume 89.djvu/145

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Experimental Electricity

��Practical Hints for the Amateur

���Wireless Communication

��The Construction of an Improved High-Tension Audion Battery

By Charles Horton

�� ��IN the early days when the audion as a detector was used only to a limited extent, it was generally considered that on account of the extremely high re- sistance of the path througii the telephones and across the vacuum in the bulb, the high-tension battery used to supply this circuit must be good for many years' work. But since the audion has been manufactured and placed on the market and its use has become wide- spread, it has been found that sometimes the dry cells used for the high-tension battery suddenlj- seem to lose their voltage in a most unaccount- able way and have to be renewed.

��therefore, it becomes necessary to test each cell of the high-tension battery, which is a tedious job; and, since the terminals of the cells are usually soldered

�� ����Fig. 2. Two other views of the switch arrangement

��to their leads, the replacing of one or more cells is a lengthy and unpleasant operation. In order to make the cells easily accessible, it is now customar>' to mount them in a bo.v separate from the audion proper, this bo.x ha\'ing on one panel the usual high-tension switch and two binding posts from which wires lead to two other posts on the audion cabinet.

��Fig. 1. Showing the arrangement switches on the case


��It has been noted by many e.vperi- menters that only certain of the cells become "dead" while the others are apparently as good as when installed. When the audion set refuses to work.

���! (S& r& iSk A r A!


��Fig. 3. View of the case with the front panel removed


�� �