The structure and symbols of a multimeter, as well as their meanings and usage methods
A multimeter consists of three main parts: the meter head, measuring circuit, and conversion switch.
Meter header
It is a highly sensitive magneto electric direct current meter, and the main performance indicators of the multimeter basically depend on the performance of the meter head. The sensitivity of the meter head refers to the direct current value flowing through the meter head when the pointer of the meter head deviates from the full scale. The smaller this value, the higher the sensitivity of the meter head. The larger the internal resistance during voltage measurement, the better its performance. There are four scale lines on the meter head, and their functions are as follows: the first line (from top to bottom) is marked with R or Ω, indicating the resistance value. When the conversion switch is in the ohm gear, this scale line is read. The second line is marked with Δ and VA, indicating the values of AC and DC voltage and DC current. When the conversion switch is in the AC, DC voltage or DC current range, and the range is in other positions except for AC 10V, this scale line is read. The third line is marked with 10V, indicating the AC voltage value of 10V. When the conversion switch is in the AC/DC voltage range and the AC voltage range is 10V, this scale line is read. The fourth item is marked with dB, indicating the audio level.
Measurement line
The measurement circuit is a circuit used to convert various measurements into small DC currents suitable for meter measurement. It consists of resistors, semiconductor components, and batteries
It can convert various different measured values (such as current, voltage, resistance, etc.), different ranges, and through a series of processes (such as rectification, shunt, voltage division, etc.) into a certain amount of small DC current and send it to the meter head for measurement.
Conversion switch
Its function is to select various measurement circuits to meet the measurement requirements of different types and ranges. There are generally two conversion switches, labeled with different gears and ranges.
