Introduction to Mechanical Multimeter and Digital Multimeter

The multimeter is one of the most common instruments. It can measure electrical quantities such as AC voltage, DC voltage, DC current and resistance. Although the accuracy of the multimeter is low, it is easy to use. Therefore, it is widely used in electrical experiments, electrical measurements, electronic measurements, etc.

Note:

　　1. Before use, check whether the pointer is pointing to the mechanical zero position. If it is not pointing to the zero position, rotate the zero adjuster on the cover to make the pointer point to the zero position.

　　2. Insert the red and black plugs of the test pen into the "+" and "-" sockets respectively. If measuring AC or DC 2500V or DC 5A, the red plug should be inserted into the corresponding sockets respectively.

　　3. When measuring unknown voltage or current, you should first select the highest range. After reading the value for the first time, you can gradually switch to the appropriate range to obtain a more accurate reading and avoid burning the circuit.

　　4. Before measuring, touch the test point with the test pen and observe the deflection of the pointer. If the pointer deflects sharply and exceeds the measuring range or deflects in the opposite direction, withdraw the test pen immediately, find out the cause and make corrections.

　　5. When measuring higher voltage, stand on a dry insulating board and operate with one hand to avoid accidents.

　　6. To avoid burning out the switch, the limit switch should be replaced when the power is cut off.

　　7. If the fuse blows out due to overload, open the meter box and replace it with the same type of fuse.

　　8. The dry batteries used in the resistor should be checked and replaced regularly to ensure measurement accuracy. If the resistor is not used for a long time, the battery should be removed to prevent electrolyte overflow and corrosion that may damage other parts.