Precautions for using ammeter
1. Correct wiring. When measuring current, the ammeter should be connected in series with the circuit under test; when measuring voltage, the voltmeter should be connected in parallel with the circuit under test. When measuring DC current and voltage, attention must be paid to the polarity of the meter, and the polarity of the meter should be consistent with the polarity of the instrument being measured.
2. Measurement of high voltage and high current. When measuring high voltage or high current, voltage transformers or current transformers must be used. The range of the voltmeter and ammeter should be consistent with the secondary rating of the transformer. The general voltage is 100V and the current is 5A.
3. Expansion of measuring range. When the measured value in the circuit exceeds the range of the instrument, an external shunt or voltage divider can be used, but it should be noted that its accuracy level should be consistent with the accuracy level of the instrument.
4. In addition, it should also be noted that the operating environment of the instrument must meet the requirements and be kept away from external magnetic fields.
