Grounding resistance testers primarily measure resistance based on the principle of potential difference. During measurement, current is injected into the grounding device through the tester, creating a potential difference between the grounding device and the auxiliary electrode. According to Ohm's law, the grounding resistance is equal to the ratio of the potential difference to the injected current. The tester integrates a precise current source and voltage measurement circuitry, enabling it to accurately measure minute potential differences and current values, thereby calculating the precise value of the grounding resistance.
