Electrical tests dielectric constant

Electrical Tests. Dielectric constant, dielectric strength, volume resistivity, power loss, power factor. 

Electrical Resistance—Conductivity. Most fillers are composed of nonconducting substances that should, therefore, provide electrical resistance properties comparable to the plastics in which they are used. However, some fillers contain adsorbed water or other conductive species that can gready reduce their electrical resistance. Standard tests for electrical resistance of filled plastics include dielectric strength, dielectric constant, arc resistance, and d-c resistance. 

Electronic and Electrical Applications. Sulfolane has been tested quite extensively as the solvent in batteries (qv), particularly for lithium batteries. This is because of its high dielectric constant, low volatUity, exceUent solubilizing characteristics, and aprotic nature. These batteries usuaUy consist of anode, cathode polymeric material, aprotic solvent (sulfolane), and ionizable salt (145—156). Sulfolane has also been patented for use in a wide variety of other electronic and electrical appHcations, eg, as a coil-insulating component, solvent in electronic display devices, as capacitor impregnants, and as a solvent in electroplating baths (157—161). 

Since the incorporation of plasticisers into a polymer compound brings about a reduction in glass temperature they will also have an effect on the electrical properties. Plasticised PVC with a glass temperature below that of the testing temperature will have a much higher dielectric constant than unplasticised PVC at the same temperature (Figure 6.6). 

The specimen may be a sheet of any size convenient to test, but should have uniform thickness. The test may be run at standard room temperature and humidity, or in special sets of conditions as desired. In any case, the specimens should be preconditioned to the set of conditions used. Electrodes are applied to opposite faces of the test specimen. The capacitance and dielectric loss are then measured by comparison or substitution methods in an electric bridge circuit. From these measurements and the dimensions of the specimen, dielectric constant and loss factor are computed. 

As previously noted, the dielectric constant, e (ASTM D-150-74), is the ratio of the capacity of a condenser made with or containing the test material compared with the capacity of the same condenser with air as the dielectric. Polymers employed as insulators in electrical applications should have low dielectric constants, while those used as semiconductors or conductors should have high dielectric constants. 

ASTM D150, 1998 (2004). Test methods for AC loss characteristics and permittivity (dielectric constant) of solid electrical insulation. 

ASTM 1986. Standard Methods Qf Test for Complex Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials at Microwave Frequencies and Temperatures 1q 1650°C. Document D 2520-86 (Reapproved 1990). Philadelphia, PA. American Society for Testing and Materials (ASTM). 

Dielectric test methods are used to measure the cure of epoxy adhesives between two conducting electrodes. This method is especially appropriate for metal-to-metal joints because the substrates themselves can be used as the electrode. The adhesive is treated as a capacitor during the test. Its response (dielectric constant, dissipation factor, etc.) over a range of electrical frequencies is measured as a function of curing time. 

ASTM D 150-87 Standard Test Methods for A-C Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials, 19 pp (DOD Adopted) (FSC 9330) (MR) (Comm D-9)... 

It can thus be assumed that one of these two mechanisms does play a decisive role in the electric conductivity of the films under discussion. However, it is not easy to distinguish between the two mechanisms, especially in the case of polymer systems. The simplest test, usually applied to crystal semiconductors, is the comparison of experimental coefficients B determined form the slope of the linear part of the j-V characteristic drawn in the Inj - V /2 system with theoretical values of that coefficient (the values of the coefficient are collected in Table II the theoretical values were calculated for dielectric constant e = 3.5). 

Electrical Data. The electrical properties of cured specimens of the epoxy resin, containing various quaternary phosphonium compounds, were obtained on 2 in. diameter discs (0.125 in. to 0.25 in. thick) using standard procedures (ASTM D150-65T). In these tests, the power factor (100 x tan 6) and dielectric constant (e ) data were usually measured at 150 C (and a frequency of 60 Hz) on resin samples which had been cured for 16 h at 135 C + 5 h at 150 C. 

Table V Indicates the good retention of electrical properties exhibited by the 40% glass-filled PPS at temperatures up to 147°C. In addition, exposure of test specimens to 50 per cent relative humidity for 5 days did not cause any appreciable change In either dielectric constant or dissipation factor. Thus, environmental factors do not have much effect upon the electrical behavior of polyphenylene sulfide resins.

Electrical Properties. The electrical properties of silicone gels are essentially the same as those of most clean, unfilled silicone elastomers and fluids. Typical values for dielectric constant and dissipation factor when tested at 25°C and 100 Hz are 2.7 to 2.9 and 0.001 to 0.002 respectively. Volume resistivity values, usually, fall in the 10 ohm- centimeter range. 

Several tests are essential for the evaluation of plastics in electrical applications. These tests include dielectric constant (permittivity ASTM-D150-74), which is the ratio of the capacitance of the polymer compared to air, dielectric strength, and dielectric breakdown voltage (ASTM-D149-75). Dielectric breakdown voltage is... 

ASTM Method D150. Methods of test for A-C loss characteristics and dielectric constant (permittivity) of solid electrical insulating materials. 

The main electrical properties related to organic materials are volume resistivity (for both conductive and nonconductive adhesives) and dielectric constant and dissipation factor (for insulative materials). Other electrical tests for conductive materials that are more application specific are electrical stability, current-carrying capacity, and interconnect resistance. 

Standard Test Method for AC Loss Characteristics and Dielectric Constant (Permittivity) of Solid Electrical Insulating Materials, ASTM D150, Am Soc. Testing and Materials. 2004. 

AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation. Primary Film Test Method ASTM D150 Additional Test Method lEC 60250. The ability of an insulator to store electrical energy can be measured through the dielectric constant, which is the ratio of the capacitance induced by two metallic plates with a film sample between them to the capacitance of the same plates with air or a vacuum between them. Better insulating materials have lower dielectric constants. Higher dielectric constants are used when high capacitance is needed. ]... 

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