What is the difference between the table ratios "10a" and "20a" of a digital multimeter?
The "10A" and "20A" marked on the test leads of the digital multimeter indicate that the test leads can carry the maximum value of the measured current. Exceeding the nominal current value may result in:
1. The test leads or their leads are heated and burned;
2. The heating of the test leads causes the conductor resistance to change, which affects the test accuracy.
This is because metal conductors with different cross-sectional areas allow different rated currents to pass. In layman's terms, the thickness is different, and the intensity of the current flowing is different. For example, the commonly used copper core wire specifications are:
When the cross-sectional area of the wire is 1.5mm², the safe current carrying capacity is 7.5A~10A;
When the wire cross-sectional area=2.5mm², the safe current carrying capacity is 12.5A~20A;
Therefore, it is necessary to choose test pens of different specifications according to the needs of measurement.
