What are the accuracy of voltage measurement in electronic measurement and instrument?
DC voltmeter is generally electromagnetic system, mainly by measuring institutions and measuring circuit of two parts. The former is mainly the stability of permanent magnet, counterproductive gossamer, change of bearing friction, the accuracy of calibration. Influence of temperature and external magnetic field. The latter, the accuracy of additional resistance.
Ohm meter, and the first question is basically the same, as well as the DC power supply (battery) voltage to be high enough, internal resistance should be small, zero adjustment to be accurate. Select the gear as far as possible to make the pointer read in the middle of the dial.
The standard table and checked in series, the standard table than the checked the accuracy of the high level two or above, to stabilize the DC current can be precisely adjusted. The current fall from zero to full deflection, observation scale value is correct or not. Consider the effects of temperature and external magnetic field.
