The marked value of resistance is inconsistent with the actual value, and the error caused by reading will lead to a large deviation between the correction table and the standard table.
When the meter is converted into a large-range ammeter, the meter will shunt the current, resulting in the measured value of the modified ammeter being less than the standard value.
Nominal error: the difference between the reading of the watt-hour meter and the accurate value, including the error caused by various imperfect factors in the structure of the watt-hour meter. In order to determine the nominal error, a modified ammeter and a standard ammeter are used to measure a certain current or voltage at the same time, thus obtaining a series of corresponding values. This work is called ammeter calibration.
Extended data:
The purpose of studying the error is: under certain conditions, get the best measurement result closer to the real value; Determine the uncertainty of the result; According to the anticipated results, reasonable experimental instruments, experimental conditions and methods are selected to reduce the cost and shorten the experimental time. Therefore, in addition to doing experiments carefully, it is equally important to have the ability to correctly express the experimental results. It is worthless to report the results without pointing out the uncertainty of the results at the same time, so we should have a correct concept of error.
Baidu Encyclopedia-Error Analysis