Product Introduction

The HC-71 Digital Earth Resistance Tester utilizes advanced medium-to-large-scale integrated circuits and employs DC/AC conversion technology to combine three-terminal and four-terminal measurement methods into a single instrument model—a novel type of earth resistance meter.

The HC-71 Digital Earth Resistance Tester operates on the principle of converting internal DC power into a low-frequency, constant AC current via an internal DC/AC converter. This current flows through a circuit formed by the auxiliary earth electrode (C) and the object under test (E), generating an AC voltage drop across the object. This voltage drop is then fed via the auxiliary potential electrode (P) into an AC amplifier for amplification, subsequently rectified, and finally displayed on the meter readout. By utilizing a range selector switch, three distinct measurement ranges can be selected: 0–2Ω, 0–20Ω, and 0–200Ω.

The HC-71 Digital Earth Resistance Tester is suitable for use in sectors such as electric power, telecommunications, railways, communications networks, and mining operations to measure the earth resistance of various installations, as well as to measure the low-resistance values of conductors. Furthermore, this instrument is capable of measuring soil resistivity and earth voltage.

Product Aliases: Digital Earth Resistance Meter, Digital Earth Resistance Tester, Earth Resistance Meter, Earth Meter, Digital Earth Meter, Earth Tester.

Technical Parameters

Product Features

◆ Structurally, the device utilizes a high-strength aluminum alloy casing. Electrically, to guard against power-frequency and radio-frequency interference, it employs a Phase-Locked Loop (PLL) synchronous tracking detection method—augmented by switched-capacitor filters—thereby endowing the instrument with superior anti-interference capabilities.

◆ The HC-2571 Digital Earth Resistance Tester employs DC/AC conversion technology to transform direct current into a low-frequency, constant alternating current, thereby facilitating accurate measurement.

◆ The instrument tolerates variations in auxiliary earth resistance within the ranges of 0–2 kΩ (RC) and 0–40 kΩ (RP) without compromising the accuracy of the measurement results.

◆ The HC-2571 Digital Earth Resistance Tester requires no manual balancing adjustments and features a 3½-digit LCD display. In addition to measuring earth resistance, it is capable of measuring low-resistance conductors, soil resistivity, and AC earth voltage.

◆ Should the test circuit be open (incomplete), the meter display will show "1," indicating an overflow condition—a standard indication consistent with conventional measurement practices.