Use and maintenance of common multimeters

There are many structural forms of multimeters, and the layout of knobs and switches on the panel varies. Therefore, before using the multimeter, you should carefully understand and be familiar with the functions of each component, and also distinguish the corresponding measurement values ​​of each scale on the panel. Pay special attention to the correct use of the multimeter, because most of the failures of the multimeter are caused by improper operation. Therefore, the correct use of the multimeter is actually the best maintenance for the multimeter. In addition, only by using the multimeter correctly can the measurement error be reduced to the minimum. The multimeter should be placed horizontally before use, and check whether the pointer is at zero. If not, adjust the mechanical zero adjustment screw in the middle of the multimeter so that the needle points to zero. Connect the red test rod to the red terminal or the jack marked with a "+" sign, and the black test rod to the black terminal or the jack marked with a "-". Turn the conversion switch to the desired position according to the object being measured. For example, when measuring AC voltage, turn the conversion switch to the corresponding interval. Some multimeters have separate type selection knobs and limit conversion knobs. When using, first turn the type selection knob to the required position corresponding to the object being measured, and then turn the limit conversion knob to the corresponding position and the appropriate limit. Pay special attention to the selection of types, otherwise it may cause serious consequences.

Precautions

(1) It is forbidden to measure insulation resistance during lightning or near high-voltage equipment. It can only be measured when the equipment is not energized and there is no induced electricity.

(2) During the shaking test, no one is allowed to work on the device being tested.

(3) The megohmmeter wires should not be twisted together and should be kept separate.

(4) Do not touch the megger with your hands before it stops rotating or the device under test is discharged. Do not touch the metal part of the lead when removing the wires.

(5) At the end of the measurement, large-capacitance devices must be discharged.

(6) Its accuracy should be checked regularly.