Calculation method of multimeter error
question:
A low-end digital multimeter of 50 yuan is often used to measure battery voltage at 20V. Once measured an accurate 1.4V voltage, this table shows 1.39, at this time the error is 0.01. When measuring multiple full lithium batteries, they are all 4.17V. This charger is an 1879 chip, and the full charge should be accurate 4.20. The seller of the charger explained that: 1.4*3=4.2, 0.01*3=0.03, 4.20-0.03=4.17. Excuse me, if there is an error in the multimeter, in the case of my example, should 4.2V be displayed as 4.19 or 4.17? Thanks!
answer:
Error: %＝0.01/1.4×100≈0.71%(0.0071)
When the error is 0.71%:
4.2×0.0071≈0.03(V)
4.2－0.03=4.17(V)
