We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Jacks and How to Use Them
487
B BATTERY
FIG. 6
When the plug is placed in the first jack, the A. F. transformer is cut out. When the plug is withdrawn, the transformer is connected, and the telephones are then placed in the second jack
of the handle was very small, which was a desirable feature in telephone practice on account of the necessity of having to place jacks as closely together as possible. The available space for making connections to the flexible cord, however, were very meagre and required a special type of cord terminals.
Now, in the radio field, the requirements are somewhat different. In the first place, the space requirements are not so rigid and furthermore there had grown up a practice among the manufacturers of head telephone receivers of attaching pin terminals to their cords. The conventional telephone plug would not take these terminals, of course, and the temporary result was that special cords were required whenever it was desired to use a plug.
This condition soon stimulated manufacturers to design a special plug for radio purposes that provided means for attaching the plug to the standard pin terminal cord. In fact, some of
the plugs on the market to-day will take practically any kind of cord tip, either pin, spade, or plain wire.
CIRCUITS EMPLOYING PLUGS AND JACKS
THE simplest circuit in which a plug and jack may be used is one involving the connection of a head set to a simple crystal or vacuum detector set with no amplification. The elements of this circuit are shown in Fig. 5. The only reason for using a plug and jack here would be in the event that it was desired to use the same head set on other sets or that it was desired to remove the head set frequently for some other purpose.
The simple jack may also be used for connecting the head set to any of the stages of a multi-stage amplifier, but with an efficiency below that which may be obtained using a pair of auxiliary springs.
The simple jack may also be used in any of
•B" BATTERY
FIG. 7
This arrangement is similar to that of Fig. 6, except for the difference in the type of jack used