1. insulation resistance: the quotient obtained by dividing the DC voltage applied between the two electrodes in contact with the sample by the total current passing through the two electrodes. It depends on volume resistance and surface resistance.

2. Volume resistance: quotient of DC voltage applied between two electrodes placed on two opposite surfaces of the sample and steady-state current flowing between the two electrodes; The current does not include the current along the surface of the material. The polarization that may form between the two electrodes is ignored. (The popular understanding is that the current through matter is blocked. )

3. Volume resistivity: the quotient of DC electric field strength and steady-state current density in insulating materials, that is, the volume resistance per unit volume.

4. Surface resistance: the quotient of the voltage applied between two electrodes on a certain surface of the sample and the current flowing between the two electrodes after a certain time; The current mainly flows through the surface layer of the sample, and also includes a part of the current component flowing through the sample volume. The polarization that may form between the two electrodes is ignored. The popular understanding is that the current is blocked when it flows on the surface of the material. )

5. Surface resistivity: the quotient of DC electric field intensity and line current density on the surface of insulating material, that is, the surface resistance per unit area.