Introduction to the header of the multimeter
Header
The head of the multimeter is a sensitive galvanometer. The dial on the head is printed with various symbols, scale marks and values. The symbol A-V-Ω indicates that the ammeter is a multimeter that can measure current, voltage and resistance. There are multiple scale lines printed on the dial, among which the one marked with "Ω" on the right is the resistance scale line, the right end is zero, the left end is ∞, and the scale value distribution is uneven. The symbol "-" or "DC" means direct current, "~" or "AC" means alternating current, and "~" means the scale line shared by AC and DC. Several rows of numbers under the scale line are the scale values corresponding to the different positions of the selector switch.
There is also a mechanical zero adjustment knob on the meter head to correct the zero position of the pointer at the left end.
Introduction to the resolution of the digital multimeter
The voltage value corresponding to the last digit of the digital multimeter on the lowest voltage range is called resolution, which reflects the sensitivity of the meter. The resolution of digital digital instruments increases with the increase of display digits. The highest resolution indicators that digital multimeters with different digits can achieve are different.
The resolution index of the digital multimeter can also be displayed by resolution. Resolution is the percentage of the smallest number (other than zero) that the meter can display to the largest number.
It should be pointed out that resolution and accuracy belong to two different concepts. The former characterizes the "sensitivity" of the instrument, that is, the ability to "recognize" tiny voltages; the latter reflects the "accuracy" of measurement, that is, the degree of consistency between the measurement result and the true value. There is no necessary connection between the two, so they cannot be confused, and the resolution (or resolution) should not be mistaken for similarity. Accuracy depends on the comprehensive error and quantization error of the internal A/D converter and functional converter of the instrument. From the perspective of measurement, resolution is a "virtual" indicator (which has nothing to do with measurement error), and accuracy is a "real" indicator (it determines the size of measurement error). Therefore, it is not possible to arbitrarily increase the number of display digits to improve the resolution of the instrument.
