Digital Multimeter Failure Causes and Preventive Measures

The most common digital meters generally have resistance measurements, on-off sound detection, and diode forward voltage measurements. AC DC voltage and current measurement, transistor amplification and performance measurement. Some increase capacitance measurement, frequency measurement, temperature measurement, data memory, and voice reporting functions, which brings great convenience to the actual detection work. However, due to improper use of the digital meter, it is easy to cause damage to the components in the watch during the actual test, resulting in malfunction. The precautions for using the digital watch in use should be used as a reference for beginners to avoid damage to the digital multimeter.

Digital multimeter failure causes and preventive measures:

1. In most cases, damage to the digital multimeter is caused by a measurement gear error. For example, when measuring AC commercial power, the measurement gear is selected to be placed in an electric barrier. In this case, once the test leads are in contact with the mains electricity, they can instantly cause a multimeter. Internal components are damaged. Therefore, be sure to check the correct measurement range before using the multimeter to measure. After use, set the measurement selection to AC 750V or DC 1000V so that no matter what parameters are measured by mistake during the next measurement, it will not cause damage to the DMM.

2. Some digital multimeters are damaged because the measured voltage and current exceeds the measuring range. If you measure the mains in the AC 20V range, it is easy to cause damage to the AC multimeter's amplifying circuit and the multimeter's AC measurement function is lost. When measuring the DC voltage, the measured voltage exceeds the measurement range and it is also easy to cause the internal circuit failure. When measuring the current, if the actual current value exceeds the range, the fuse in the multimeter will generally only be blown and will not cause other damage. Therefore, when measuring the voltage parameters, if you do not know the approximate range of the measured voltage, you should first put the measurement file to the highest level, and then measure the value and then shift the measurement to get a more accurate value. If the value of the voltage to be measured is far beyond the maximum range that the multimeter can measure, a high-impedance meter should be added. For example, detect the second anode high voltage and focus high voltage of black and white color TV.

3. The DC voltage range of most digital multimeters is 1000V. Therefore, when the DC voltage is measured, the highest voltage value is less than 1000V. Generally, the multimeter will not be damaged. If it exceeds 1000V, it is very likely to damage the multimeter. However, the measurable voltage limits of different DMMs may vary. If the measured voltage exceeds the range, it can be measured using a resistive voltage drop method. In addition, when measuring the high DC voltage of 40O ~ 1000V, the test leads must be in good contact with the measurement site and must not be subject to any jitter. Otherwise, in addition to the damage caused by the multimeter and the inaccurate measurement, it is also possible to make the multimeter without any seriousness. display.

4, in the measurement of resistance, it should be noted that the measurement must not be charged.