. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. ELECTRICAL MEASUREMENT 7S in conjunction with the variable capacitance, a frequency range of about 100 cycles to 150 Fig. 2—Single-frequency vacuum tube oscillator used as secondary standard of frequency The meter is calibrated by balancing the circuit by means of the variable resistance and capacitance with a known frequency input, and recording the coil and condenser settings. It is used for checking frequencies by reversing the process, that is, connecting the
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. ELECTRICAL MEASUREMENT 7S in conjunction with the variable capacitance, a frequency range of about 100 cycles to 150 Fig. 2—Single-frequency vacuum tube oscillator used as secondary standard of frequency The meter is calibrated by balancing the circuit by means of the variable resistance and capacitance with a known frequency input, and recording the coil and condenser settings. It is used for checking frequencies by reversing the process, that is, connecting the source of unknown frequency to the bridge, balancing as before, and determining the frequency by reference to the calibration. There are no input or output transformers connected to this circuit and on this account certain precautions must be taken in connecting the output and input circuits to it; but it is a relatively low impedance circuit, and troubles due to this cause have not been found serious. Resistance. A convenient secondary standard of resistance is a dial box having the resistance units designed to meet the same require- ments as the prime standards. Commercial dial boxes are available, having satisfactory stability with variations in frequency and atmos- pheric conditions, and having sufificiently small phase angles for all frequencies but the highest radio frequencies. A dial box, requiring, as it does, a certain amount of wiring between dials, and having all of the dials connected permanently whether they. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original American Telephone and Telegraph Company. [Short Hills, N. J. , etc. , American Telephone and Telegraph Co. ]
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
