Introduction to How the Accuracy (Uncertainty) of a Digital Multimeter Is Calculated
The accuracy of a multimeter, also known as uncertainty by some manufacturers, is generally stated as "within one year of leaving the factory, measured at an operating temperature of 18 ° C~28 ° C (64 ° F~82 ° F) and a relative humidity of less than 80%, ± (0.8% reading+2 characters). "Many buyers or users are not very clear about this and often ask. I assume here that there is an instrument that, in a certain range, such as DC 200V, is written like this, and the measured value is displayed as 100.0 on the instrument. So, what should be the correct value at this time. I think for ordinary users, they can completely ignore accuracy calculations and simply assume that DC 100V is sufficient. According to the manufacturer's accuracy calculation, when measuring 100V (displaying 100.0), the error is ± (0.8% * 1000+2)=± 10, which is an error of 1.0V. When substituting the reading, do not consider the decimal point, use the displayed value to calculate. The calculated value should add the decimal point and then use the original reading to calculate the shipping cost. For example, the correct value is 100.0 ± 1.0, which should be between 99.0~101.0V DC.
I am a novice and I want to learn electronic maintenance. What kind of multimeter do I want to purchase
In general, friends who are just starting out can buy a popular multimeter (a multimeter, named after its ability to measure voltage, current, and resistance at the same time). The most commonly used function is resistance, followed by DC voltage. The additional functions of a multimeter, such as diode, buzzer, transistor, and capacitor measurement, are also commonly used. Therefore, it is recommended to consider purchasing an instrument with this function. Of course, there are some skilled maintenance personnel who may have their own unique maintenance methods, which is another matter.
