Multimeter structure, meaning of each symbol and how to use it
A multimeter consists of three main parts: meter head, measurement circuit and transfer switch.
Header
It is a highly sensitive magnetoelectric DC ammeter. The main performance indicators of the multimeter basically depend on the performance of the meter head. The sensitivity of the meter refers to the DC current value flowing through the meter when the meter pointer deflects at full scale. The smaller the value, the higher the sensitivity of the meter. The greater the internal resistance when measuring voltage, the better its performance. There are four scale lines on the meter head, and their functions are as follows: The first one (from top to bottom) is marked with R or Ω, indicating the resistance value. When the switch is in the ohm position, this scale line is read. The second bar is marked with ∽ and VA, indicating the AC and DC voltage and DC current values. When the transfer switch is in the AC, DC voltage or DC current position, and the range is in other positions except AC 10V, this scale is read. Wire. The third bar is marked 10V, which indicates the AC voltage value of 10V. When the transfer switch is in the AC and DC voltage range and the measurement range is AC 10V, this scale line is read. The fourth bar is marked in dB and indicates the audio level.
Measuring line
The measurement circuit is a circuit used to convert various measured objects into tiny DC currents suitable for meter measurement. It is composed of resistors, semiconductor components and batteries.
It can transform various measured objects (such as current, voltage, resistance, etc.) and different ranges into a certain amount of tiny DC current after a series of processing (such as rectification, shunting, voltage division, etc.). The meter head is used for measurement.
transfer switch
Its function is to select various measurement lines to meet the measurement requirements of different types and different ranges. There are generally two transfer switches, each marked with different gears and ranges.
