The earth resistance tester is a commonly used device in sectors such as electricity, postal services, railways, communications, and mining for measuring ground resistance. It discards the traditional manual hand-cranked power generation method and employs advanced large-scale integrated circuits. It applies DC/AC conversion technology to merge the three-terminal and four-terminal measurement methods into one. This instrument is known for its simplicity of operation, precise measurements, and high-precision electrical testing capabilities. In this article, ATO industrial automation will briefly introduce earth resistance tester to you, including its working principle, usage method, advantages, applications etc., to help you have a better understanding of it.