Balance: when the default position is tilted forward and backward by 90 degrees, the allowable error range of the instrument is ± 1 mm. Internal impedance: 650ohm±10%. Insulation resistance: 500V DC of case and circuit plus 50m ohm or higher. Zero position: use the default position of the instrument. The point where the front end of the pointer coincides with the center of the zero scale is the reference pointer and zero overlap scale. The tolerance is ± 1 mm. Standard test conditions: temperature 20 ℃, humidity 70%, if there is no difference in the test results, you can also test under normal temperature and humidity. Current sensitivity: the scale range of the pointer is from zero to the maximum scale (full scale position), and the sensitivity is 960ua ± 8%. Pointer sticking: when the full scale current instantly triples the over-current and slowly reduces the current reading sensitivity from 1/2, the pointer return to 1/3 of the scale. Friction: when the current is applied to the instrument and slowly increases or decreases to a certain value, the error range of the indication point is ± 1 mm., Manufacturer: Jnchdghwa