ASTM D2149:13(R2021) pdf free download – Standard Test Method for Permittivity (Dielectric Constant) and Dissipation Factor of Solid Dielectrics at Frequencies to 10 MHz and Temperatures to 500 °C.
10. Temperature Control
10 1 Take measurements at frequent temperature intervals (not to exceed 0 °C). until the required temperature range has been traversed. Reduce the temperature to the lowesi required test temperature and leave until equilibrium has been achieved. Determine equilibrium by clamping a specimen between the holder electrodes and balancing or peaking the measuring circuit until no change takes place between balances made 2 mm apart. After the required measurements have been made at the lowest test temperature increase the temperature at the rate of 2 ± 0.5 °C/min to the next test temperature. Follow this procedure for achieving the test temperature until the required temperature range has been traversed. Take measurements at approximately the same test temperatures as the temperature is increasing and as the temperature is decreasing. Measurements as temperature is being increased and decreased are necessary to guard against possible hysteresis in electrical properties due to such factors as moisture and chemical change.
11. Conditioning
11.1 Prior to applying electrodes condition the specimens at
23 ± 1 °C and 50 ± 2 % relative humidity for a minimum of
40 h. Carry out room-temperature tests in the Standard Laboratory Atmosphere of 23 ± 1 °C and 50 ± 2 % relative
humidity.
12. Procedure A (Using 11icrometer Electrode)
12.1 Refer to Test Methods Dl50. Center the specimen between the electrodes and rotate the drive nut until the friction is felt to suddenly decrease. Read this micrometer setting and check it against the setting at which the friction first increases on increasing the electrode spacing. Balance or peak the measuring circuit. Open the electrodes and remove the specimen. Then restore the balance of the measuring apparatus without changing its capacitance setting by reducing the spacing between the electrodes and adjusting the measuring circuit to balance the loss component. Note the new dissipation factor and micrometer setting, and so forth.
12.2 At each test temperature and each required frequency determine the capacitance and dissipation factor of each specimen.
16. Report
16.1 Report the following:
16.1 . I Description of the specimen, including name, grade, color, and manufacturer,
16.1.2 Dimensions of test specimen.
16.1.3 Conditioning of test specimen and type of secondary electrodes,
16.1.4 Measuring circuit and procedure.
16.1.5 Test voltage, and
16.1.6 Permittivity and dissipation factor at each temperature and frequency reported.
17. Precision and Bias
17.1 Precision—The precision of this test method has not been determined.
17.2 Bias—The bias of this test method has not been determined.
18. Keywords
18.1 dielectric constants; dissipation factors; micrometer electrodes; permittivities; precision capacitors; relative permittivities.