How to Make Commercial Type Radio Apparatus: A Guide Book for Those Who Desire to Make Their Equipment the Equal, in Appearance as Well as Performance, of the Commercial Apparatus
How to Make Commercial Type Radio Apparatus: A Guide Book for Those Who Desire to Make Their Equipment the Equal, in Appearance as Well as Performance, of the Commercial Apparatus
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 edition. Excerpt: ...The Precision Wavemeter, Fig. 91, to eliminate errors and variations due to elaborate circuits, contains only a condenser, of the type just described, a type 425 Weston thermogalvanometer, and the inductance coil. With five coils a range of Z5 to 24,000 meters can be obtained. No exciting means is ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 edition. Excerpt: ...The Precision Wavemeter, Fig. 91, to eliminate errors and variations due to elaborate circuits, contains only a condenser, of the type just described, a type 425 Weston thermogalvanometer, and the inductance coil. With five coils a range of Z5 to 24,000 meters can be obtained. No exciting means is furnished, for, in accurate work, such excitation is not required. The use of a buzzer calls for a special calibration, when it is in use, and at best causes errors of too great a magnitude for such a precision instrument. By the elimination of losses in the condenser and wiring, and by winding the inductance coils with high frequency cable in a manner to make the distributed capacity minimum, an accuracy is obtained which permits the determination of the resonance point for undamped waves to less than one-half a division on the vernier scale, which is equivalent in wavelength to 1 part in 10,000. The wavemeter is carried in a mahogany case, fitting in a strong whitewood carrying box which also holds the coils and calibration data. Mahogany boxes, with bakelite ends, are used to mount the inductances. The general design of the instrument is intended to combine strength with accuracy of reading. The wavelength calibration is made at 24 points for each coil, and a capacity calibration at 26 points on the condenser is also furnished. CHAPTER VI BALDWIN TYPE TELEPHONE RECEIVERS During the last few years the United States and other governments have used Baldwin telephones, but it is only recently that they have been available for experimenters. While they have become familiar now, identified by the mica diaframs, their action is not apparent even to those who have looked inside. It is generally known that they are proportionately more sensitive to...
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