The difference in test accuracy of small resistance of multimeter
Now multimeters in all walks of life have become the basic tools for everyone. According to the different accuracy of use, hand-held multimeters are divided into three and a half digits, four and a half digits, five and a half digits and other models. Multimeters are powerful and can be used to test voltage, current, resistance, etc. Now, in order to facilitate everyone's use, high-end multimeters are also equipped with functions such as diode, capacitance, resistance, and insulation resistance testing.
When engaged in automotive electronics, power electronics, etc. and need to test the characteristics of small resistance, some manufacturers will use the resistance test gear of ordinary multimeters to test, but from a professional point of view, we recommend that the resistance below 30Ω should not be tested by the two-wire method. , Our company compares the typical three-and-a-half-digit, four-and-a-half-digit, five-and-a-half-digit multimeters and micro-ohmmeters with four-wire method for comparison. Assuming that the resistance of 1Ω is tested, the accuracy is expressed as 0.1% of the reading + the last 5 digits (differences between different products), the comparison is as follows:
From the comparison table, we can see that when the resistance is 1Ω, the uncertainty of the high-precision five-and-a-half-digit multimeter test can reach 5%, while the accuracy of the multimeter using the four-wire method can reach 0.35%, so when considering the test When the resistance is small, a micro-ohmmeter for four-wire method testing is essential.
Considering the practicality and convenience of the multimeter, Germany GMC-I has added the micro-ohmmeter function to the four and a half digit multimeter, which can meet the convenient use of working platforms such as automotive electronics and power components.
4½-digit true RMS digital multimeter METRAHIT AM series
True RMS 12,000 Digits display
Cutting-edge technology permeates every detail. METRAHIT AM series high-end multimeters are durable and show convincing high-performance characteristics in all aspects. They are equipped with state-of-the-art technology that ensures highly accurate results. Its ergonomic design provides maximum ease of use and safety. With its powerful and versatile features, it is ideal for demanding measurement tasks in a variety of applications.
Features
• Resolution: ±12,000 digits, 4½ digits
• 3-hole socket with patented self-locking socket (ABS)
• Equipped with authoritative DAkkS certificate as standard
• 15mm character height large screen with backlight
• TRMS AC/DC function
• Voltage measurement basic accuracy ±0.05% (V DC)
• Automatic manual range optional
• Auto hold storage: DATA / MIN / MAX
• Safety rating: 1000 V CAT III and 600 V CAT IV
• V (AC, DC, AC+DC), A (AC, DC, AC+DC, with current clamp), resistance, °C, conduction, diode, Hz (V, A), capacitance, duty cycle
