The voltage on the precision resistor is connected to the output voltage connector and the internal four-position AC/DC current meter. The gear selector on the precision current shunt panel selects one of the five gears and outputs it to a four-and-a-half-digit voltmeter, a four-and-a-half voltmeter measures more accurate AC or DC current values. For higher accuracy or resolution current displays, a five-and-a-half-digit or better meter can be used to connect to the output voltage connector. 

 The precision current shunt has five very stable and precision resistors (0.001, 0.01, 0.1, 1 and 10 Ω) that can be used to measure AC and DC currents from 0.02A to 220A. The principle of AC and DC current measurement is based on Ohm's law: I=V/R, and the current flowing through the resistor is the voltage across the resistor divided by the resistance. Because the precision current shunt uses extremely stable and accurate resistors, a reliable and accurate current can be obtained.

The precision current shunt basically has the same function as the AC and DC ammeter in the digital multimeter, but the precision current shunt provides a higher accuracy of less than 0.01%, a better temperature coefficient is generally less than 10PPM/°C and a wider range up to 220A.
 
With the technical improvement of precision current shunts and the change of production process, its precision is also getting higher and higher. At present, many smart meters and other precision instruments are widely used in precision shunts. The precision shunts produced by MICROHM Electronics are listed as MMS8420, MMS5930 and MMS3820. The number of applications in smart meters, new energy vehicles and other products has increased the most, and it has also been well applied in more high-end instruments.