(1) Since the overload capacity of the magnetoelectric ammeter is very small, you must pay attention to the polarity and quantity limit of the connection circuit when using it.
(2) If it is found that the pointer deflection in the reverse direction or the forward direction exceeds the full scale line on the scale during the measurement, the power should be cut off immediately to stop the measurement, and the measurement should be performed after the correct connection or the reselection of a higher limit ammeter.
(3) When the measurement is completed, the power should be turned off first, and then the ammeter should be removed from the measurement circuit, and placed in a dry, ventilated and cool environment. For microammeters and milliammeters with high sensitivity and accuracy, use wires to connect the positive and negative terminals to protect the measuring mechanism of the meter.
The use and maintenance methods of voltmeters are similar to those of ammeters, and the following points should also be noted:
(1) Connect the voltmeter to the circuit under test in parallel during measurement.
(2) Since the voltmeter and the load are connected in parallel, the internal resistance Rv is required to be much larger than the load resistance RL.
(3) When measuring DC, first connect the "-" button of the voltmeter to the low potential end of the circuit under test, and then connect the "+" terminal button to the high potential end of the circuit under test.
(4) For multi-limit voltmeters, when the limit needs to be changed, the voltmeter should be disconnected from the circuit under test before changing the limit.
Jan 21, 2023
