Dielectric spectroscopy
（重定向自Polarization of dielectrics）
![A dielectric permittivity spectrum over a wide range of frequencies. The real and imaginary parts of permittivity are shown, and various processes are depicted: ionic and dipolar relaxation, and atomic and electronic resonances at higher energies. From the Dielectric spectroscopy page of the research group of Dr. Kenneth A. Mauritz.](/Images/godic/202502/03/Dielectric_responses.svg3825.png")
![CSIRO Dielectrics spectroscopy machine](/Images/godic/202502/03/CSIRO_ScienceImage_10377_Dielectrics3825.jpg")
![Fig. 1 : Steady-state current density vs. overpotential for a redox reaction.](/Images/godic/202502/03/ButlerVolmer13825.png")
![Fig. 2 : Equivalent circuit for a redox reaction without mass-transfer limitation.](/Images/godic/202502/03/CircuitRctCdlparallele3825.png")
Dielectric spectroscopy (sometimes called impedance spectroscopy), and also known as electrochemical impedance spectroscopy (EIS), measures the dielectric properties of a medium as a function of frequency. It is based on the interaction of an external field with the electric dipole moment of the sample, often expressed by permittivity.