Routine use and maintenance of digital multimeter

First, turn on the power of the digital multimeter, and then select the object to be measured, whether it is voltage, current, resistance or other quantity. The next step is the range. If you are not sure of the parameter, you can set it to the maximum range, and then gradually reduce the range. Before measuring, you should also check whether the test lead is in the correct hole position. When turning the range switch, use moderate force to avoid possible damage to the switch metal sheet. After use, it is best to put the functional range switch in the high voltage position.

2. A few notes on the test of digital multimeter
(1) For high resistance, it is normal for the test results of resistance to be different from those of pointer meter. This is mainly due to slightly different test conditions.
(2) When testing physical quantities of related polarity, the polarity display corresponds to the test lead. That is, when the polarity is not displayed, the red test lead contact is the high potential or the current inflow end, and when the polarity display is "-", the red test lead contact is the low potential or the current outflow end.
(3) The resistance block and diode block are different from the pointer meter. When the pointer meter measures resistance, the red and black test leads have opposite polarity to the test source, that is, the black test lead is the positive end of the test source and the red test lead is the negative end. However, the digital meter has the same polarity as the test source, that is, the red test lead is the positive end of the test source and the black test lead is the negative end, which is consistent with the voltage and current block. This will not cause confusion and is superior to the pointer meter.
(4) For transistors whose polarity or pin arrangement order is unknown, the transistor hfe block can be used to repeatedly change the pins to detect and identify the electrodes of the transistor.
(5) Calibration.
Digital multimeters should be calibrated regularly. When calibrating, a digital instrument of the same type or with higher accuracy should be used. The calibration should be carried out in the order of first calibrating the DC range, then the AC range, and finally the capacitance range.
Digital multimeters often use a 9V laminated battery, which generally needs to be replaced after a few months of use. It is recommended to purchase a 9V rechargeable battery instead. This nickel-cadmium rechargeable battery model is GP-15F8K. It is exactly the same as an ordinary 9V laminated battery.