Dielectric loss angle

Dissipation factor (loss tangent) lEC 250. As explained in the chapter, this is the tangent of the dielectric loss angle and is now more commonly used than the power factor, which is the sine of the loss angle. When the angle is small the two are almost identical (e.g. for a loss angle of 10° the difference is about 1.5%). 

Typically, large-scale gas filling makes the main characteristics of foam plastics — coefficients of heat and temperature conductivity, dielectric permeability, and the tangent of the dielectric loss angle — totally independent of the chemical structure of the original polymer [1],... 

The variations of dielectric constant and of the tangent of the dielectric-loss angle with time provide information on the mobility and concentration of charge carriers, the dissociation of defect clusters, the occurrence of phase transitions and the formation of solid solutions. Techniques and the interpretation of results for sodium azide are described by Ellis and Hall [372]. 

Dielectric loss angle (symbol 5) An angle between the vector for the amplitude of the total current and that for the amplitude of the charging... 

The most noticeable difference between syntactic foams with the same filler but different binders is seen in the tangent of the dielectric loss angle (Table 25)11(. If glass microspheres replace organosilicon ones for the same binder, not only tan 8, but also e decrease 1). But also the dielectric properties and the concentration of the binder affect the final foam s e (Fig. 18) n). 

Dielectric loss factor The product of the dielectric constant and the tangent of the dielectric-loss angle for a material. 

Fig. 17. Dependence of the dielectric permeability e and of the tangent of dielectric loss angle tg8 on the apparent density of rigid oligomeric foams. Epoxide - PE-8 (1) and PE-9 (2) polyurethane - PPU-204 (3), PPU-305 A (4) andPPU-307 (5) )...

Ffg. 24. Dependence of dielectric perme ability e (1), tangent of dielectric loss angle (2), specific volume resistance (3) and water absorption (4) on the curvii period for epoxide foams (7 = 35 kg m ) at 98% relative humidity... 

Figure 3.30. Dependence of tangent of dielectric losses angle on temperature of initial and modified PETP - samples 1 - initial PETP 2 - PETP + 0,1% of HC-2 3 - PETP + 0,5% of HC-2 4 - PETP + 3,0% of HC-2.

IB. the dielectric loss angle, representing relaxation phenomena. 

The dissipation factor, DF, is the ratio of the resistive (loss) component of current to the capacitive component of current, 7c, and equals the tangent of the dielectric loss angle, 5, as follows ... 

S = the dielectric loss angle analogous to the mechanical loss angle e = the complex dielectric constant = the static or low fiequency value of the dielectric constant,... 

Fig. 7. Tangent of the dielectric loss angle versus the temperature in the preoriented sample of polymer la. 

Tan of dielectric loss angle n. In an ideal condenser of geometric capacitance Q, in which the polarization is instantaneous, the charging current Eros Cq is 90° out of phase with the alternating potential. In a condenser in which absorptive polarization occurs, the current also has component E(os"Cq in phase with the potential and determined by Ohm s law. This ohmic or loss current, which measures the absorption, is due to the dissipation of part of the energy of the field as heat. In vector notation, the total current is the sum of the charging current and the loss current. The angle d between the vector for the amplitude of the total current and that... 

The dielectric loss factor (loss factor) of a material is the product of the dielectric constant and the tangent of the dielectric loss angle for a material. This is a measure of how easily the material will heat up in a high-frequency field such as a radio frequency or microwave frequency oven. 

Jurkawska et al. [66] investigated the effect of fullerene and carbon black on the properties of rubber. In addition to beneficial improvements to physical properties such as elastic modulus fullerene at the 0.06-0.75 phr level, also affected were electrical properties such as dielectric loss angle and permittivity. 

Figure 8.8 Current /, voltage U and power P of a capacitor. Without a dielectric, the phase shift between / and U is exactly 90°, but in the presence of a dielectric it is (90°-6), where 6 is the dielectric loss angle.

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