How is the accuracy (uncertainty) of a digital multimeter calculated?
Answer: The accuracy of the multimeter is also called uncertainty by some manufacturers, which generally reads "within one year from the factory, the operating temperature is 18°C ~ 28°C (64°F ~ 82°F), and the relative humidity is less than 80%. , ±(0.8% reading + 2 digits)." Many buyers or users are not very clear about this and often ask. I assume here that there is a meter, in a certain range, such as DC 200V, it is written like this, the measured value displays 100.0 on the meter, then the correct value at this time should be. I think that for the average user, you can completely ignore the precision calculation and directly think that it is DC 100V. According to the manufacturer's accuracy calculation, when measuring 100V (display 100.0), the error is ±(0.8%*1000+2)=±10, that is, the error is 1.0V. When substituting the reading, do not consider the decimal point to display Substitute the value into the calculation, add the decimal point to the calculated value, and then use the original reading to go to the freight, like this example, then the correct value is 100.0±1.0, which should be between 99.0 and 101.0V DC.
