Precautions for using ammeter and voltmeter

(1) Be careful when moving and disassembling the meter, handle it with care, and avoid severe vibration or impact to avoid damage to the meter parts, especially the bearings and hairspring.

(2) When installing or disassembling the meter, the power supply should be cut off first to avoid personal injury or damage to the measuring device.

(3) Before connecting the meter to the circuit, you should first estimate whether the current and voltage to be measured on the circuit are within the maximum range of the meter to avoid overloading the meter and damaging it. When selecting the maximum range of the meter, it is best to use 1.5 to 2 times the value being measured.

(4) When measuring current, the ammeter should be connected in series with the circuit being measured; when measuring voltage, the voltmeter should be connected in parallel with the circuit being measured. When measuring DC current or DC voltage, pay special attention to the connection between the "+" terminal of the meter and the "+" terminal of the power supply, and the connection between the "-" terminal of the meter and the "-" terminal of the power supply. When measuring AC current or AC voltage, there is no need to pay attention to polarity.

(5) The lead wire of the meter must be appropriate, able to bear the load during measurement without overheating, and not causing a large voltage drop that affects the meter reading. If the meter has a dedicated wire, it should be connected to the dedicated wire when in use. The connection part should be clean and reliable to avoid poor contact that affects the measurement effect.

(6) The pointer of the meter should always be adjusted to zero. Normally, the pointer should point to zero. If it is slightly off, adjust the zero adjustment screw on the meter to return the pointer to zero.

(7) The meter should be cleaned regularly with a dry soft cloth to keep it clean.