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large interference current, this symbol flashes and displays, and
the instrument emits a "beep-beep-beep--" prompt sound. The
accuracy of the test cannot be guaranteed at this time.
VIII. Principle of Resistance Measurement
The basic principle of the clamp-type grounding resistance
tester to measure the grounding resistance is to measure the loop
resistance. See below. clamp meter
The mouth part is composed of a voltage coil and a current
coil. The voltage coil provides the excitation signal and induces
a potential V on the loop under test. Under the action of the
potential V, a current I will be generated in the circuit under test.
The clamp meter measures V and I, and the measured resistance
R can be obtained by the following formula.
R=V/I
