Forbidden Operations When Using Analog Multimeters
① Ensure correct position selection.When measuring AC voltage, first turn the selector switch to the AC voltage range; when measuring DC current, it shall be switched to the DC current range. For DC measurement, pay attention to the polarity of test leads and avoid misconnection.When measuring resistance, turn the selector switch to the resistance range, short the two test leads for zero adjustment, then connect the two test leads to both ends of the measured resistance component. Multiply the reading indicated by the meter pointer by the multiplier of the selector switch to get the resistance value of the component under test.
② Ensure correct wiring.When measuring DC current, first turn the selector switch to the DC current range, then connect the multimeter to the circuit under test. The red test lead connects to the positive pole and the black test lead to the negative pole; reverse connection will damage the meter.
③ Select an appropriate measurement range. Switching ranges under live power is prohibited, whether the range selected is too large or too small.
④ It is prohibited to directly measure microampere meter movements, galvanometers and standard batteries using the ohm range of the multimeter.
⑤ When measuring transistor parameters, avoid using the R×1 and R×10 ranges, and do not use the R×10k range.
⑥ Measuring resistance under live conditions is prohibited.
⑦ Remove the batteries if the multimeter will not be used for a long time to prevent battery leakage and damage to the instrument.
