Routine use and maintenance of digital multimeter
First turn on the power of the digital multimeter, and then select whether the object to be measured is voltage, current, resistance or other quantities. The next step is the range. If the parameter cannot be determined, it can be set to the highest range, and then gradually reduce the range. Before measuring, check whether the test leads are in the correct hole position. Use moderate force when toggling the range switch to avoid possible damage to the metal sheet of the switch. After use, the function range switch is best placed in the high-voltage gear.
2. A few points in the test of the digital multimeter
1) For high resistance, it is normal that the test results of the resistance are different from the test results of the pointer meter. This is mainly due to slightly different test conditions.
(2) When testing the physical quantities related to polarity, the polarity display corresponds to the test leads. That is to say, when the polarity is not displayed, the contact of the red test lead is the highest potential or the current inflow end, and when the polarity shows "-", the contact of the red test lead is the low potential or the current outflow end.
(3) The electric block and the diode block are different from the pointer table. When measuring resistance with a pointer meter, the polarity of the red and black test leads is opposite to that of the test source, that is, the black test lead is the positive terminal of the test source, and the red test lead is the negative terminal. However, the polarity of the digital meter is consistent with the test source, that is, the red test lead is the positive terminal of the test source, and the black test lead is the negative terminal, which is consistent with the voltage and current block. This will not confuse and is superior to pointer tables.
(4) For the triode whose polarity or pin arrangement sequence is unknown, the electrodes of the triode can be identified and determined through the triode hfe gear changing pin detection multiple times.
(5) Calibration.
The digital multimeter should be calibrated regularly. When calibrating, a digital instrument of the same type or with higher precision should be selected, and the DC gear should be calibrated first, then the AC gear should be calibrated, and the capacitance gear should be calibrated in the last order.
Digital multimeters often use a 9V laminated battery, which usually 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. Exactly the same as ordinary 9V laminated batteries.
