Modeling of four-electrode system to determine the resistance of antistatic coatings – Optimizing the size of the measurement area

• A system to determine of the resistivity of thin antistatic coatings was proposed.
• Several models were developed to analyze the theoretical properties of the system.
• The distance between electrodes and object edge was assessed for error reduction.
• The experimental data confirm the theoretical considerations.

In the paper, mathematical models for determination of resistivity of thin antistatic coatings are presented. The models use the four-points method and the method of images. The relations between the sample size and the distance between the electrode set and the edge of the sample were analyzed. It was found that the distance between the electrode set and the object edge should be at least 5 times greater than the electrode spacing to allow us using much simpler formulas for infinite flat object with measurement uncertainty below 5%. The correctness of theoretical considerations was verified experimentally.