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Show th:aild by o. Doul V ararup. tJllor of Kudlo AlorcUundldlng. ) u 1 0 r 1 Cfc- w rramc J Smyle Opon Circuit 6ije Circuif 1 ' 1 ' imfle Closed Circuit .Devble Circuit' fiuffmaii Filament Te be I ' I .' . 3r I' , , TELEPHONE kJACKS Double Circuit Wiring Diagram of Principal Types of Jacks. Because telephone jacks are widely used in many kinds of radio sets, tlie radio fan would do well to familiarize himself with the various types. There are five different styles, nnd as many as three of them are used In the same receiver. The jack most commonly employed Is the double circuit. It Is placed between be-tween the successive steps of audio frequency amplifiers, and when the telephone plug is removed from it the next tube Is automatically connected. The double circuit jack has four springs, which are insulated from each other and from the frame. Normally, with no plug In it, the inner springs press against the outer ones. In the better jacks silver tips are used at the point of coutact. When the phone plug Is inserted the Inner leaves are disengaged disen-gaged and the tip of the plug makes connection with the lower outer spring, while the sleeve touches the upper outer one. The single closed-circuit jack has only one outer and one inner spring. The tip of the plug touches tlie lip of tlie long spring, while the sleeve connection is made directly on the brass frame. The single open-circuit model la similar. Automatic filament jacks have extra sets of springs to control the battery circuit of the tubes. When properly wired the tubes will be all out when all the jacks used are empty, even though the rheostats are turned on. When the phone plug Is Inserted only the tubes up to that jack are lighted and no others. When the plug is removed re-moved the entire set goes dead. The wiring of these filament jacks is rather complicated, but they are so convenient conveni-ent that the trouble Is well worth while. There are only two types, single sin-gle and double circuit. The double one is similar to the regular single closed circuit one and the single circuit is like the single open circuit regular model. The symbols used to represent jacks in diagrams are practically pictures pic-tures of them, so they are rather easy to follow. New York Globe. |
