1、 Structural features

2、 Overview
2.1 Basic functions and standards:
The M-3 handheld four probe tester is a versatile and cost-effective measuring instrument that uses the principle of four probe measurement to test material resistivity/block resistance. The design of this instrument complies with national standards such as GB/T 1551-2009 "Method for Measuring the Resistivity of Silicon Single Crystals" and GB/T 1552-1995 "DC Four Probe Method for Measuring the Resistivity of Silicon and Germanium Single Crystals", and references the American A.S.T.M standard.
2.2. Matching composition: The standard configuration consists of two parts: an M-3 host and an optional four probe probe. It can also be equipped with a test bench for use as a desktop computer.
2.3 Advantages and characteristics:
1. Beautiful and applicable: Colorful streamlined handheld panel with anti slip pad, ergonomically designed. Suitable for handheld and variable occasions, and can also be customized with small travel suitcases for easy outdoor or travel use.
2. High precision: M-3 handheld four probe square resistance meter with complete thickness and shape correction functions, so the testing is correct. Most handheld devices in the industry are simple programs without complete correction functions, so they cannot correct thickness and shape correction errors.
3. Wide range: It has an ultra wide range of five gears, equivalent to the range of a mid range desktop computer. In the industry, handheld devices mostly have two to three gears, with limited testing range and limited adaptability.
4. Easy to operate and stable performance: Touch the digital keyboard to achieve parameter setting and function conversion, which is simple and eliminates the instability and interference of analog locators.
5. Manual/automatic integration:
6. The display method is beautiful and clear: displayed by a bright green digital and LED digital meter head, not afraid of dark environmental background or strong outdoor light;
7. Long standby and working time (no less than two days), powered by a large capacity rechargeable lithium battery, environmentally friendly and durable.
2.4 Probe Selection: There are multiple options available for probes based on different material characteristics. Please refer to the "Reference Table for Model, Specification, and Feature Selection of Four Probe Probes" for details
1. Equipped with highly wear-resistant tungsten carbide probe probes, such as the ST2253-F01 type, to test the resistivity/square resistance of hard materials such as semiconductors, metals, and conductive plastics such as silicon;
2. A spherical or flat headed gold-plated copper alloy probe probe without damaging the film, such as the ST2558B-F01 type, can measure the resistivity/square resistance of thin film coatings on metal foil, carbon paper, and other conductive films, as well as ceramic, glass, or PE film substrates, such as metal coating, spray coating, ITO film, capacitance convolution film, and other materials.
3. Equipped with a dedicated foil coating probe, such as the ST2558B-F02 model, it can also test the resistivity/square resistance of foil coating on lithium battery electrodes and other materials.
4. Replacing with a four terminal test fixture can also measure the body resistance of the resistor.

2.5. Test bench selection: According to different material characteristics, there are multiple options available for the test bench. For details, please refer to the "Reference Table for Model, Specification, and Feature Selection of Four Probe Test Bench"
Select SZT-A type, SZT-B type (electric), or SZT-C type (fast constant pressure) test bench for testing solid or thin film materials using the four probe method.
Select SZT-K type testing bench for testing slender rod materials using the two probe method
SZT-G type testing bench is selected for testing rubber and plastic materials using the parallel four blade method.
2.6. Scope of application: handheld use, the instrument is suitable for testing the conductivity of conductors, semiconductors, and semiconductor like materials using the four probe method in semiconductor material factories, device factories, research institutions, and universities.

3、 Basic technical parameters
1. Measurement range and resolution
Resistance: 0.010 Ω~50.00k Ω, resolution 0.001 Ω~0.01 kΩ
Resistivity: 0.010 Ω - cm~20.00 kΩ - cm, resolution 0.001 Ω~0.01 kΩ - cm
Block resistance: 0.050 Ω/□~100.00 kΩ/□ Resolution 0.001 Ω~0.05 kΩ/□
2. Measurable material size
The handheld method is not limited to material size, but the addition of a test bench is determined by the optional test bench as follows:
SZT-C test bench direct testing method 180mm × 180mm.
Length (height): Test bench direct testing method H ≤ 100mm.
Measurement orientation: both axial and radial directions are acceptable.
3. Range division and error level (extended range in parentheses)

4) Charger working power supply: M-3 host power supply DC4.2V, power consumption: <1W 

                           Power Adapter: Input: 220V±10%, 50Hz, Output: DC8.4V±10%, 0.5A

5) Boundary dimension: W × H × L=10 cm × 3.6 cm × 21 cm
Net weight: ≤ 0.5 kg