Polarization Lag
Energy dissipation occurs in a non-ideal capacitor when the polarization of the insulating material lags behind the applied alternating electric field. This dielectric hysteresis represents the internal friction of molecular dipoles as they attempt to realign with a shifting potential. The effect is particularly pronounced in ferroelectric ceramics used for micro-scale energy storage.
It results in a loop-shaped curve when plotting charge density against electric field strength. Designers must account for this energy loss to prevent overheating in high frequency circuits.
Material Permittivity
The ability of a substance to store electrical energy is influenced by its atomic structure and temperature. As the frequency of the signal increases, dielectric hysteresis causes the effective permittivity to drop. This change impacts the timing of signal filters and oscillators.
Loss Tangent
Quantifying the efficiency of an insulator requires measuring the ratio of energy lost to energy stored. Technicians use a vector impedance analyzer to determine the phase angle of the current. The magnitude of dielectric hysteresis is then derived from the tangent of the loss angle.
Thermal Dissipation
Heat generated by molecular friction can degrade the physical integrity of a component over time. Excessive dielectric hysteresis leads to a rise in internal temperature. This process is monitored during accelerated life testing.
