Analysis of the error of measuring the same voltage with different ranges of multimeter
The accuracy level of multimeter is generally divided into several levels such as 0.1, 0.5, 1.5, 2.5, 5 and so on. DC voltage, current, AC voltage, current and other gears, accuracy (precision) level of the calibration by its maximum absolute permissible error △ X and the percentage of the full-scale value of the selected range. Expressed by the formula: A% = (△X/full scale value) × 100%
The error generated by measuring the same voltage with different ranges of a multimeter
For example: MF-30 type multimeter, the accuracy of 2.5 level, the choice of 100V block and 25V block to measure a 23V standard voltage, ask which block error is small?
100V block maximum absolute allowable error: X (100) = ± 2.5% × 100V = ± 2.5V.
25V block maximum absolute allowable error: △ X (25) = ± 2.5% × 25V = ± 0.625V.
From the above, it can be seen that: measuring 23V standard voltage with 100V stop, the display value on the multimeter is between 20.5V and 25.5V. Measuring 23V standard voltage with 25V stop, the value on the multimeter is between 22.375V-23.625V. From the above results, △X (100) is greater than △X (25), i.e., the error of the 100V block measurement is much larger than the error of the 25V block measurement. Therefore, when a multimeter measures different voltages, the errors generated by measuring with different ranges are not the same. In the case of meeting the value of the signal to be measured, you should try to choose a stop with a small range. This can improve the accuracy of the measurement.
Multimeter can not only be used to measure the resistance of the measured object, AC and DC voltage can also measure DC voltage. Some multimeters can even measure the main parameters of transistors and capacitors. Fully master the use of multimeter is one of the most basic skills of electronic technology. Common multimeters include pointer multimeters and digital multimeters. Pointer multimeter is a multi-functional measurement instrument with a head as the core component, and the measurement value is read by the pointer of the head. Digital multimeter measurement value by the liquid crystal display directly in the form of digital display, easy to read, some also with voice prompts. Multimeter is a common head, set of voltmeter, ammeter and ohmmeter in one instrument.
