Measurement error between current and resistance range using a multimeter
When measuring with a multimeter, there may be some errors. Some of these errors are the maximum absolute errors allowed by the accuracy level of the instrument itself.
Some are Personal equation caused by improper adjustment and use. By correctly understanding the characteristics of a multimeter and the reasons for measurement errors, mastering the correct measurement techniques and methods, measurement errors can be reduced.
Human reading error is one of the reasons that affects measurement accuracy. It is inevitable, but it can be minimized as much as possible. Therefore, special attention should be paid to:
1. Before measuring, the multimeter should be placed horizontally and mechanically zeroed;
2. Keep your eyes perpendicular to the pointer when reading;
3. When measuring resistance, zero should be adjusted every time the gear is changed. Replace the battery with a new one if it cannot be adjusted to zero;
4. When measuring resistance or high voltage, it is not allowed to hold the metal part of the meter pen with your hand to prevent the human body's resistance from diverging, increasing measurement error or electric shock;
5. When measuring the resistance in the RC circuit, cut off the power supply in the circuit and discharge the electricity stored in the capacitor before measuring.
After excluding human reading errors, we conducted some analysis on other errors.
one、 Selection of voltage and current ranges and measurement errors of a multimeter
The accuracy level of a multimeter is generally divided into several levels, such as 0.1, 0.5, 1.5, 2.5, and 5. The calibration of accuracy level for various gears such as DC voltage, current, AC voltage, and current is represented by the maximum absolute allowable error △ X and the percentage of the selected full scale value. Expressed by the formula: A%=(△ X/full scale value) × 100%... 1
(1) The error caused by measuring the same voltage using a multimeter with different accuracies
(2) The error caused by measuring the same voltage using different ranges of a multimeter
(3) The error caused by measuring two different voltages using the same range of a multimeter
