Resistivity is an important parameter of resistance. Generally, resistivity test is affected by many factors, usually temperature environment, test environment and voltage have great influence on resistivity. In order to get accurate resistivity, engineers are controlling the environment and temperature, so what is the important effect of voltage on resistivity? Let us analyze it below.           

First, we understand that the resistivity of dielectric materials generally cannot be kept constant over a wide range of voltages, in which case Ohm's law is not suitable for use in such cases. Under normal temperature conditions, in the lower voltage range, the electrical conductivity increases linearly with the increase of the applied voltage, and the resistance of the resistive material remains unchanged. Secondly, if the ionization motion is intensified after a certain voltage is exceeded, the increase of the electric conduction current is much faster than the test voltage, and the resistance value of the resistance material is rapidly decreased. It can be seen that the higher the applied test voltage, the lower the resistance value of the resistive material, so that the resistance value of the material tested under different voltages may have a large difference.

The determinant of the change in material resistance is the electric field strength at the time of testing, not the test voltage. For the same test voltage, if the distance between the test electrodes is different, the test results of the material resistivity will be different. The smaller the distance between the positive and negative electrodes, the smaller the test value. From the last two points, we clearly understand that voltage has a very important influence on resistivity. The resistivity we may measure at different voltages also varies greatly. When applying resistors, engineers must test the resistors with a certain test resistor to get the correct resistivity.