How to connect the instrument to avoid measurement errors without load and short circuit tests
A ruler, a total of 1 meters long. But is it really 1 meters long? The ruler may be due to manufacturing reasons, will be slightly a bit longer or shorter.
What's more, winter and summer have different temperatures, thermal expansion and cold contraction, and this ruler will also vary in length. But when you take this ruler to measure a thing, you think it is 1 meters long. Even if your measurement method is accurate, the measurement error caused by the error of the ruler's own system can never be avoided. Random errors, each measurement may be slightly different, but generally will fluctuate around the average. The more the number of measurements, the closer the average value to the actual value (already included the system error). That is to say, when the number of measurements is enough, the random error can be eliminated.
There are two kinds of errors, systematic error and random error. System errors can not be avoided, depending on the quality of the instruments you use. Take a very simple example.
