Circuit diagram inside the ohmmeter

Probe domestic high current needle 150 head diameter 3.0 thread needle high current needle total

The figure shows the internal circuit diagram of the ohmmeter. Only one trimmer resistor is used throughout the measurement range. The D1 and D2 diode boxes are used to protect the meter head from damaging the meter when the unknown resistance is higher than the selected process. Once the ohmmeter is installed, place a precision 30KΩ resistor in the test Rn position. And set the measurement range 10KΩ, adjust RV1 to full scale.