What is the calculation of the accuracy (or uncertainty) of a digital multimeter?
The accuracy of a multimeter, also known as uncertainty by some manufacturers, is generally stated as "within one year of leaving the factory, the operating temperature is between 18 ° C and 28 ° C (64 ° F to 82 ° F), and the relative humidity is less than 80% when measured, ± (0.8% reading+2 words)." Many buyers or users are not very clear about this and often ask. I assume here that there is an instrument in a certain range, such as the DC 200V range, which is written as follows. The measured value displayed on the instrument is 100.0. What should be the correct value at this time. I think for the general user, they can completely ignore the accuracy calculation and simply consider it as DC 100V. 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, and use the displayed value to calculate. The calculated value should be added with the decimal point and the original reading should be used to calculate the shipping cost. In this example, the correct value is 100.0 ± 1.0, which should be between 99.0 and 101.0V DC.
How to use a multimeter to detect damaged electronic products or household appliances?
This problem is very complex,. For electronic product maintenance, home appliance repair, or computer brain maintenance, everyone has their own methods and cannot be generalized. Overall, a multimeter is just a tool with many functions (that is, it can measure many parameters). By proficiently measuring the parameters of various circuits or components, and combining them, the fault can be determined. For example, by measuring the voltage of a certain section of the circuit to determine whether it is working properly; Determine whether a component is functioning properly by measuring its resistance; Determine whether a component is open, short circuited, or deteriorated by measuring its capacitance. Wait a minute. So a multimeter is just a tool. After DIY fans buy it, they should also participate in various forums or extracurricular classes to strengthen their own literacy and improve their ability to use the tool. Finally, for example, a multimeter is like a sword, and its power lies in its owner. With a few tenths of martial arts skills (electronic knowledge), it can achieve several tenths of its effectiveness.
