Routine Use and Maintenance of Digital Multimeters
Firstly, turn on the power of the digital multimeter, and then select whether the measured object is voltage, current, resistance, or other quantity. The next step is the range. If the parameters cannot be determined, they can be set to the maximum range and gradually reduced. Before measurement, it is also necessary to check whether the probe is in the correct hole position. When turning the range switch, the force should be moderate to avoid possible damage to the switch metal sheet. After use, it is best to place the function range switch in the high voltage position.
Several explanations in the testing of digital multimeters
(1) It is normal for the resistance test results to differ from the pointer meter test results for high resistance. This is mainly due to slightly different testing conditions.
(2) When testing physical quantities related to polarity, their polarity display corresponds to the probe. That is to say, when polarity is not displayed, the red probe contact is the potential or current inflow end. When polarity is displayed as "-", the red probe contact is the potential low end or current outflow end.
(3) The resistance range and diode range are different from the pointer gauge. When measuring resistance with a pointer meter, the red and black probes have opposite polarity to the test source, that is, the black probe is the positive end of the test source, and the red probe is the negative end. However, the polarity of the digital meter is consistent with that of the test source, with the red probe indicating the positive end of the test source and the black probe indicating the negative end, which is consistent with the voltage and current levels. This will not confuse and is superior to pointer tables.
(4) For transistors with unknown polarity or order of pin arrangement, the electrodes of the transistor can be identified and determined by multiple pin changes in the hfe gear of the transistor.
(5) Calibration.
Digital multimeters should be calibrated regularly, and similar or higher precision digital instruments should be selected for calibration. The calibration should be carried out in the order of first calibrating the DC gear, then calibrating the AC gear, and finally calibrating the capacitor gear.
Digital multimeters often use a 9V stacked battery, which usually needs to be replaced after a few months of use. Suggest purchasing a 9V rechargeable battery as a replacement. The model of this nickel cadmium rechargeable battery is GP-15F8K. It is exactly the same as a regular 9V stacked battery.
