Causes of digital multimeter malfunctions and precautions:
1, digital multimeter damage in most cases is caused by the measurement of the wrong gear, such as in the measurement of the AC mains, the measurement of the gear selection is placed in the resistance block, in this case, once the pen contact with the mains, instantly can cause damage to the internal components of the multimeter. Therefore, before using the multimeter to measure, you must check whether the measuring position is correct. At the end of the use, the measurement selection will be placed in the AC 750V or DC 1000V, so that in the next measurement, no matter what parameters are measured by mistake, it will not cause damage to the digital multimeter.
2,Some digital multimeters are damaged because the measured voltage and current exceed the range. Such as in the AC 20V gear measurement of utility power, it is easy to cause damage to the digital multimeter AC amplifier circuit, so that the multimeter loses the AC measurement function. When measuring DC voltage, the measured voltage exceeds the measuring range, which is also easy to cause the failure of the internal circuit of the meter. When measuring current, if the actual current value exceeds the range, it will only cause the fuse in the multimeter to blow, and will not cause other damages. Therefore, when measuring voltage parameters, if you don't know the approximate range of the measured voltage, you should first put the measurement gear at 0, and then change the gear after measuring its value to get the comparative ** value. If the voltage value to be measured is far beyond the * large range that the multimeter can measure, it should be equipped with another high resistance measuring pen. Such as the detection of black and white colour TV ** anode high voltage and focus high voltage.
3, most of the digital multimeter DC voltage upper range for 1000V, so when measuring DC voltage, the highest voltage value in 1000V below, generally will not damage the multimeter. If it exceeds 1000V, it is likely to cause damage to the multimeter. However, the upper limit of measurable voltage may vary from one digital multimeter to another. If the measured voltage exceeds the range, it can be measured by resistor step-down method. In addition, in the measurement of 40O ~ 1000V DC high voltage, the pen and the measurement must be in good contact, there can not be any jitter, otherwise, in addition to possible damage to the multimeter to make inaccurate measurements, and in serious cases, the multimeter can also be made without any display.
4,When measuring resistance, it should be noted that it must not be measured with electricity.
