Precautions for Use, Advantages, and Causes of Damage of Digital Multimeters
Digital multimeters are popular among radio enthusiasts due to their advantages of convenient measurement, value taking, and complete functions. Ordinary digital square meters generally have resistance measurement, on-off sound detection, and diode forward conduction voltage measurement. AC/DC voltage and current measurement, transistor amplification factor and performance measurement, etc. Some digital multimeters have added functions such as capacitance measurement, frequency measurement, temperature measurement, data memory, and voice reporting, which bring great convenience to practical testing work. However, improper use of digital meters can easily cause damage to the components inside the meter and result in malfunctions during actual testing.
In most cases, damage to a digital multimeter is caused by measurement gear errors. For example, when measuring AC power, if the measurement gear is set to the resistance gear, once the probe contacts the power, it can instantly cause damage to the internal components of the multimeter. Therefore, before using a multimeter for measurement, it is necessary to check whether the measurement gear is correct. After use, place the measurement selection at AC 750V or DC 1000V, so that no matter what parameter is mistakenly measured in the next measurement, it will not cause damage to the digital multimeter.
Some digital multimeters are damaged due to the measured voltage and current exceeding the range If measuring the mains power in the 20V range, it is easy to cause damage to the AC amplifier circuit of the digital multimeter, causing the multimeter to lose its AC measurement function. When measuring DC voltage, if the measured voltage exceeds the measurement range, it can also easily cause circuit faults in the meter. When measuring current, if the actual current value exceeds the range, it usually only causes the fuse in the multimeter to burn out and will not cause any other damage. So when measuring voltage parameters, if the approximate range of the measured voltage is not known, the measurement gear should be set first, and the value should be measured before shifting gears to obtain a comparative value. If the voltage value to be measured far exceeds the maximum range that the multimeter can measure, a high resistance measuring probe should be provided separately. To detect the anode high voltage and focusing high voltage of black and white color TVs.
