摘要 :
The document establishes standards for the manufacture, testing, storage, packing and transportation of thermistors. Detailed specifications in tabular and schematic form show the authorized physical configurations and basic elect...
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The document establishes standards for the manufacture, testing, storage, packing and transportation of thermistors. Detailed specifications in tabular and schematic form show the authorized physical configurations and basic electrical parameters for thermistors of standard design. Technical test criteria are outlined, including authorized deviations from established standards.
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摘要 :
A method has been developed for evaluating the power sensitivity linearity of Model 478A, 478A-H75, and 8478A, thermistor mounts manufactured by Hewlet Packard Company Inc., Palo Alto. This method provides the thermistor mount pow...
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A method has been developed for evaluating the power sensitivity linearity of Model 478A, 478A-H75, and 8478A, thermistor mounts manufactured by Hewlet Packard Company Inc., Palo Alto. This method provides the thermistor mount power sensitivity curve as measured power approaches the maximum rated power of the thermistor mount. This characteristic is essential to the accuracy of power ratio measurements. Selection of thermistor mounts, linear within 0.001 dB over a 15 dB range, is possible. This is a ten-fold improvement over the previous 0.01 dB value used. This improvement was required for the enhanced certification of 10 dB attenuators needed in the calibration support of attenuation measurement, power calibration, and network analyzer systems. (ERA citation 13:030897)
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摘要 :
A method of calibration for sophisticated test equipment has been developed. This technique has been adapted for use with automatic attenuation measurement systems. After the equipment has been set up, the procedure operates witho...
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A method of calibration for sophisticated test equipment has been developed. This technique has been adapted for use with automatic attenuation measurement systems. After the equipment has been set up, the procedure operates without intervention. (ERA citation 12:020813)
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摘要 :
Application specifications for the methane sensor were assembled and design guidelines, development goals and evaluation criteria were formulated. This was done to provide a framework to evaluate sensor performance and any design ...
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Application specifications for the methane sensor were assembled and design guidelines, development goals and evaluation criteria were formulated. This was done to provide a framework to evaluate sensor performance and any design adjustments to the preprototype sensor that could be required to provide methane sensitivity. Good response to hydrogen was experimentally established for four hydrogen sensor elements to be later evaluated for methane response. Prior results were assembled and analyzed for other prototype hydrogen sensor performance parameters to form a comparison base. The four sensor elements previously shown to have good hydrogen response were experimentally evaluated for methane response in 2.5% methane-in-air. No response was obtained for any of the elements, despite the high methane concentration used (50% of the Lower Flammability Limit). It was concluded that the preprototype sensing elements were insensitive to methane and were hydrogen specific. Alternative sensor operating conditions and hardware design changes were considered to provide methane sensitivity to the preprototype sensor, including a variety of different methane sensing techniques. Minor changes to the existing sensor elements, sensor geometry and operating conditions will not make the preprototype hydrogen sensor respond to methane. New sensor elements that will provide methane and hydrogen sensitivity require replacement of the existing thermistor type elements. Some hydrogen sensing characteristics of the modified sensor will be compromised (larger in situ calibration gas volume and H2 nonspecificity). The preprototype hydrogen sensor should be retained for hydrogen monitoring and a separate methane sensor should be developed.
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