ZST-121 Solid Insulating Material Volume Resistivity and Surface Resistance Tester

ZST-121 Solid Insulating Material Volume Resistivity and Surface Resistance Tester fully complies with the national standard GB1410-2006 Test methods for insulation resistance, volume resistivity and surface resistivity of solid electrical insulating materials, and ASTM D257 Test methods for DC resistance or conductance of insulating materials. This instrument, equipped with different measuring electrodes (fixtures), can measure the volume resistivity and surface resistivity or conductivity of different materials (solid, powder, or liquid). It is suitable for measuring the volume and surface resistance values of various insulating materials in rubber, plastic, film, powder, liquid, solid, and paste forms. In addition to measuring resistance, this instrument can also directly measure weak currents.



II. Technical Specifications



No.  

Item

Parameter

1

Resistance measurement range

1×104Ω ～1×1018Ω

2

Current measurement range

2×10-4A～1×10-16A

3

Display mode

Digital LCD display

4

Built-in test voltage

10V , 50V, 100V, 250V, 500V, 1000V

5

Basic accuracy

1%

6

Operating environment

Temperature: 0℃～40℃, relative humidity <80%

7

Power supply

AC 220V, 50HZ, power consumption approx. 5W

8

Instrument dimensions

285mm× 245mm× 120 mm

9

Weight

Approx. 5KG

10

Compact size, light weight, high accuracy

Dual display of resistance and current, stable performance, easy reading

11

Measuring ultra-high resistance is as simple as using a multimeter to measure ordinary resistance

Eliminates the inconvenience of old-style high resistance meters that require multiplying by coefficients under different test voltages or ranges




III. Working Principle



    According to Ohm's law, the measured resistance Rx equals the applied voltage V divided by the passing current I. The working principle of traditional high resistance meters is to fix the measurement voltage V and obtain the resistance value by measuring the current I flowing through the sampling resistor. From Ohm's law, since current I is inversely proportional to resistance, not directly proportional, the displayed resistance value is nonlinear. That is, when resistance is infinite, current is zero, so the zero position of the meter is at ∞, and the scale near it is very dense with low resolution. The entire scale is nonlinear. Moreover, when measuring different resistances, the voltage V may also vary, so ordinary high resistance meters have poor accuracy and low resolution.

    This resistivity tester simultaneously measures the voltage V across the resistor and the current I flowing through it, uses a large-scale integrated circuit to perform the division of voltage by current, and then converts the result through A/D conversion to display the resistance value digitally. Even if the voltage V across the resistor and the current I flowing through it change simultaneously, the displayed resistance value does not vary with changes in the measured voltage V or current I as in ordinary high resistance meters. Therefore, even if the measurement voltage, measured resistance, or power supply voltage changes, the impact on the result is minimal, and the measurement accuracy is very high (patented). Theoretically, the error can be zero, while in practice, the error can be as low as a few thousandths or ten-thousandths.



IV. Typical Applications



1. Measuring insulation material resistance (resistivity)

2. Measuring resistance and resistivity of antistatic materials

3. Measuring system resistance of raised floors in computer rooms

4. Measuring resistance of antistatic shoes and conductive shoes

5. Dark current measurement of photodiodes

6. Physics, optics, and materials research